Friday, March 31, 2017

Can My Breast Cancer Come Back?

As you come to the completion of your breast cancer treatments, it seems unfair to think you might have to deal with it again in the future. For many patients, treating breast cancer can be a painful, unpleasant experience, and once your doctor says you're clear of it, it seems like you should be able to carry on without ever having to worry about getting cancer again. But unfortunately, cancer can recur, and some breast cancer survivors struggle with anxiety for the rest of their lives over whether their cancer will come back. Upon completing surgery, radiation or chemotherapy, many patients assume that they're done with treatment and can move on. Some may even assume that simply finishing chemo means they're cured.

But Dr. Melissa Pilewskie, a surgical breast oncologist at Memorial Sloan Kettering Cancer Center in New York, says, "we tend to think of completing treatment as finishing surgery, chemotherapy and radiation. But a lot of women still have treatment going on for years." In the first year after the initial treatments have concluded, "many women will be on some kind of pill," often an anti-estrogen pill or other drug therapy to help prevent cancer cells from regenerating. Dr. Maggie DiNome , associate professor of surgery at the UCLA Santa Monica Breast Center at the David Geffen School of Medicine at UCLA, says that some women with hormone-positive breast cancer will be on drug therapy for upwards of five years.

And only after they complete that treatment can they be considered "cured." Still, even after being cancer-free for any length of time, it's possible your cancer could come back, although DiNome says the risk isn't as high as many women fear. For most women with breast cancer – those who developed the disease without a genetic mutation to aid it – the risk for recurrence is about 6 percent over 15 years, she says. And it's critical to put the fear of recurrence in an appropriate context for patients, she says. "You don't want patients to live a lifetime of anxiety that it's going to recur." At the same time, finally reaching the point where they can be considered cancer-free can create a strange feeling for some women. "When they're in active treatment and they're doing everything you ask them to do, they're comfortable being watched and tested. But then they reach their five-year mark off treatment and you're just monitoring them. That's a tricky scenario for some women – they almost feel like all of the sudden the net's been pulled out from under them," DiNome says. Pilewskie agrees.

"During treatment, most patients feel empowered, that they're doing something to deal with the disease. But once that stops, there can be a fear of what happens next. It's a waiting game of wondering whether something is going to happen. It can be hard emotionally to get back to a healthy lifestyle from that standpoint, and I'll often refer patients struggling with this for counseling and support groups." Recurrence can happen after a period of remission. Pilewskie refers to remission as "no evidence of disease," and this is when treatment will shift from actively battling the cancer to monitoring your body going forward.

 According to the American Cancer Society,"if cancer is found after treatment, and after a period of time when the cancer couldn't be detected, it's called a cancer recurrence." The ACS classifies the different types of recurrence you may experience as local recurrence, regional recurrence or distant recurrence. With a local recurrence, the cancer comes back in the original place it started. In regional recurrence, it returns to the lymph nodes near where it started. And in distant recurrence, the cancer comes back in another part of the body. The ACS reports that "the less time between when the cancer was thought to be gone and the time it came back, the more serious the situation. There's no standard length of time to decide if it's recurrence or progression. But most doctors consider recurrence to be cancer that comes back after you've had no signs of it for at least a year."

Progression, on the other hand, refers to cancer that never fully disappeared and continues to grow and change in the body. For example, if you're diagnosed with Stage 2 cancer and the disease progresses, you could be reclassified as having Stage 3 or 4 cancer. Also, if the cancer metastasizes, or invades a new organ, that would be considered a progression. In some cases, patients can be thought to have been in remission and then the cancer progresses, indicating that the first treatment protocol did not kill all of the cancer and additional treatment is needed. If it's determined that your cancer was in remission and at some point thereafter, cancer is again detected in your body, your doctor will run diagnostic tests to determine whether it's a recurrence or a new cancer altogether (called a second primary cancer); if it's the same type as you originally battled, chances are it's a recurrence. If it's a different type or has a different progression, then it's probably a second cancer.

The ACS reports that developing a second cancer "is much rarer than cancer recurrence, but it does happen. Having cancer once does not mean you cannot get another type of cancer in the future." Pilewskie says that having had breast cancer "does slightly increase the risk for a subsequent case." She also says that there are some second cancers that can be associated with breast cancer, but it's not necessarily the breast cancer itself that's caused this second illness; often there's an underlying genetic reason a person battles cancer more than once. The BRCA1 and BRCA2 genes are perhaps the most widely known genetic mutations associated with breast cancer, though there are other genetic factors that can predispose a person to cancer or elevate your risk for developing a second type of cancer. "Depending on the family history and genetics, breast and ovarian cancer are the two most commonly associated cancers, but in people with these genetic mutations, we also see an increase in pancreatic cancer. For men with these genes, breast cancer, prostate cancer, and some carcinomas may be associated." And what's more, simply surviving cancer – and living longer – can be its own risk factor for recurrence or developing a second cancer. According to, "the aging process is the biggest risk factor for breast cancer. That's because the longer we live, there are more opportunities for genetic damage (mutations) in the body. And as we age, our bodies are less capable of repairing genetic damage."

 Although as a whole, any kind of cancer can come back, Pilewskie says your chances of it returning can vary depending on the type of cancer you've had. "The more aggressive cancers may recur faster." With more aggressive forms of breast cancer, if it doesn't recur within the first two years, most likely you can be considered "cured." With slower-growing cancers, the cancer can return much later. Although many breast cancer survivors worry about their cancer coming back "sometimes I think that women overestimate their risk," Pilewskie says. She encourages anyone who's completed breast cancer treatment to have "a good conversation with their doctor about their actual risk of recurrence." Although there's no surefire way to prevent your cancer from coming back, there are a few lifestyle choices you can make to help reduce the chances. These are virtually the same things you're advised to do to help reduce your risk of developing breast cancer in the first place: eating right, controlling stress, getting enough sleep, managing your weight, participating in routine screening and exercising. It's this last item – exercise – that Pilewskie says she thinks holds the most promise for the future of cancer recurrence prevention.

"I just got back from a surgical oncology meeting and exercise is a hot topic. It's going to really come out in the research over the next few years what the specific links are" between breast cancer and exercise. She says she's hopeful that research will pinpoint a specific dose of exercise that's beneficial that doctors can prescribe their patients to reduce recurrence. "There's a lot of data looking at the impact of exercise on women to improve survival and lower recurrence rates. I think it's a complicated relationship in the effect of exercise and dietary factors," but she says breast cancer patients and survivors should strive to get back to a normal exercise routine as soon as possible. And be sure to keep all your follow-up appointments.

Wednesday, March 29, 2017

Prostate, Hair Loss Drugs Not Tied to Suicide Risk

Drugs used to treat enlarged prostate and male pattern baldness may raise an older man's risk of depression and self-harm, but not their risk of suicide, a new study finds. The study focused on a class of medications called 5a- reductase inhibitors (5ARIs), which include widely used drugs for male pattern baldness, such as Propecia, and Proscar, used to fight an enlarged prostate gland.

Researchers led by Dr. Blayne Welk, of Western University in Ontario, Canada, noted that "there have been concerns raised by patients and regulatory agencies regarding serious psychiatric adverse effects" in users of 5ARIs. To learn more, Welk's team tracked data on more than 93,000 Canadian men, aged 66 and older. The men had started a new prescription for a 5ARI medication between 2003 and 2013. Although the study wasn't designed to prove cause-and-effect, some psychiatric trends were seen.

The men had an 88 percent increased risk of self-harm in the first 18 months of starting on 5ARIs, but that risk disappeared after that point. Their risk of depression rose by 94 percent during the first 18 months and continued to be elevated after that, but to a much lesser degree, the findings showed. However, the study did not show any elevation in suicide risk for men taking the drugs, according to the report published online March 20 in JAMA Internal Medicine. Overall, the researchers said that the absolute risk of psychiatric effects to any one patient remain low.

"And the potential benefits of 5ARIs in this population likely outweigh these risks for most patients," the study authors concluded. Two physicians -- a urologist and a psychiatrist -- believe the findings should be included in discussions between patients and their doctors. Also, "at the first follow-up visit after initiating the medication, physicians will need to ask patients about depression-related symptoms," said Dr. Manish Vira. He's vice-chair of urologic research at The Arthur Smith Institute for Urology, part of Northwell Health in Lake Success, N.Y. However, Vira agreed with the study authors that the medications "do provide significant benefits to patients with regards to prostate-related urinary symptoms and should continue to be an option for treatment."

 Dr. Richard Catanzaro is chief of psychiatry at Northern Westchester Hospital in Mt. Kisco, N.Y. He pointed out that both enlarged prostate and male pattern baldness are not life-threatening conditions. So the new study raises questions about the merits of treating these conditions with 5ARIs if psychiatric symptoms are taken into consideration, he said. "The study also raises several other interesting issues: Is it the physician's role to decide what constitutes quality of life? Does the slight risk that a medication may cause an increase in depression and self-harm outweigh the benefits of treating a non-life-threatening condition that someone feels severely impacts their life?"

Catanzaro said. "In some cases, for example, someone with [an enlarged prostate] may awaken several times during the night to use the bathroom. Is that worse than being depressed? Quality of life is an issue that must be the basis of a conversation between the patient and the physician," he said. According to Catanzaro, open communication about drugs and their potential side effects is key. "Physicians should have a comprehensive conversation with their patients about the known risks of these medications and whether they believe these are outweighed by potential benefits," he said.

Tuesday, March 28, 2017

Vitamin D Fails To Reduce Cancer Risk in Postmenopausal Women

Supplementation with vitamin D3 and calcium did not significantly reduce the risk of cancer among postmenopausal women, according to a randomized, controlled study published in JAMA.

Some studies showed an inverse relationship between vitamin D levels and cancer risk. The purpose of this trial was to evaluate the effect of vitamin D3 supplementation on cancer risk. This trial randomly assigned 2303 postmenopausal women to receive 2000 IU of vitamin D3 and 1500 mg of calcium per day or placebo for 4 years, with follow-up up visits every 6 months.

At baseline, the mean age was 65, 99% were non-Hispanic Caucasian, and the mean serum 25-hydroxyvitamin D level was 33 ng/mL. The mean serum 25-hydroxyvitamin D levels rose to 43.9 ng/mL by 12 months and was maintained during the 4-year study. In the placebo group, the mean serum 25-hydroxyvitamin D level remained around 31 ng/mL throughout the study.

At 4 years, 3.89% of women in the vitamin D3 group and 5.58% in the placebo group were diagnosed with cancer (difference, 1.69%; 95% CI, -0.06-3.46%; P = .06), resulting in an incidence of 0.042 (95% CI, 0.032-0.056) and 0.06 (95% CI, 0.048-0.076; P = .06), respectively. Vitamin D supplementation was not associated with reduced cancer risk with a hazard ratio of 0.70 (95% CI, 0.47-1.02). The lack of association may be a result of the higher baseline serum levels of 25-hydroxyvitamin D compared with the general US population, according to the authors.

Friday, March 17, 2017

Research Found the Quickest, Least Painful Way to Up Your Cardio

What are your most common reasons for missing your workout? Too busy? No money for a gym? No equipment? Too complicated? Too hard? We have good news—and not only do you not need to buy anything from an infomercial, but there's hard science showing it really works. What is this miracle workout? It's as simple as going up stairs.

Doing just a few minutes a day of intense stair-climbing offers many of the same heart-healthy benefits as taking a class at the gym or jogging around the block, according to a new study published in the journal Medicine & Science in Sports & Exercise. And you don't even need a fancy stair-climber machine—any old staircase will do.

Researchers recruited healthy but sedentary women to run up and down a staircase for short bursts—the first group did three sets of 20-second stair-climbing and a second group ran up and down the stairs for 60 seconds. Including a brief warm-up and cool-down, the women spent less than 10 minutes a day (about 30 minutes per week, total), exercising. Yet even though they worked out very little, they still experienced significant cardiovascular and respiratory improvements, the researchers found. It may sound too good to be true, but there's a lot of science to support this type of short-but-intense training.

The secret? Stair-climbing is a particularly effective form of interval training. High-intensity interval workouts have been a fitness darling for decades, offering a wide variety of health benefits. But previous research has tested interval training on equipment like treadmills or stationary bikes—which is great, if you have them. This new study, however, proves that the ordinary staircase going down to your basement or behind your office is every bit as good, not to mention way cheaper and easier to get to. Finding an hour to go to the gym, change, wait for equipment, exercise, shower, and drive home again is daunting for many people.

But who doesn't have two minutes to take a quick sprint up the stairs in between laundry trips? "Stair-climbing is a form of exercise anyone can do in their own home, after work, or during the lunch hour," said Martin Gibala, Ph.D., lead author and a professor of kinesiology at McMaster University, in a press release. "Interval training offers a convenient way to fit exercise into your life, rather than having to structure your life around exercise."

Exercise better than drugs for cancer fatigue

Cancer patients may ease fatigue more effectively with exercise and psychotherapy than with medication, a recent study suggests. Researchers examined data from 113 previously published studies involving more than 11,500 cancer patients with fatigue. Patients were randomly assigned to treat their exhaustion with exercise or psychotherapy, or both, or with drugs. Exercise and psychotherapy were associated with a 26 percent to 30 percent reduction in fatigue during and after cancer treatment, the study found.

Drugs, however, were tied to only a 9 percent decline in fatigue. "Patients need to try exercise or psychotherapy before they reach for a pharmaceutical," said lead study author Karen Mustian of the University of Rochester Medical Center in Rochester, New York. Cancer-related fatigue is common and may be tied to the effects of tumors or treatments, researches note in JAMA Oncology. Unlike other types of exhaustion, just getting more sleep or giving aching muscles a break from strenuous activities can't address fatigue associated with tumors. Fatigue tied to cancer can persist for years and may be worsened by other cancer-related health problems like depression, anxiety, sleep disturbance and pain. It's not clear why exercise and psychotherapy may be more effective than drugs, Mustian said by email.

"We do not know for sure why exercise works, but some research is beginning to suggest it is due to anti-inflammatory effects and also improvements in physical function - cardiovascular, pulmonary and muscular," Mustian added. "In terms of psychotherapy, the most beneficial form was group therapy that used a cognitive behavioral approach to educate patients, help them to change the way they think about fatigue and managing it, and adopting behaviors to help alleviate it." Most participants in the studies were female, and almost half of the studies involved women with breast cancer. Age, gender, cancer type and forms of exercise didn't appear to influence how effective exercise or psychotherapy was relative to medications, researchers found.

Overall, the analysis included 14 drug studies, mostly looking at stimulants or drugs designed to promote wakefulness. Among the 69 evaluations of exercise, most looked at aerobic activity alone or in combination with other types of movement. Of the 34 psychological interventions tested in the studies, most involved therapies focused on behavior and education. One benefit of the current study is that researchers were able to pool the data from several individual research efforts that were, alone, too small to draw meaningful conclusions about the relative advantages of different treatments, the authors note. Limitations include the varied designs in the studies, which made it difficult to assess how factors such as race, education, income or other demographic differences might have impacted the results, the researchers also point out.

Even so, the findings confirm previous research on interventions to ease cancer-related fatigue, Dr. Jens Ulrich Rueffer, head of the German Fatigue Society in Cologne, said by email. "We already knew that exercise and/or psychological interventions were beneficial for treating cancer-related fatigue," said Kerry Courneya, a researcher at the University of Alberta, in Edmonton, Canada. "What we learned from this new meta-analysis is that exercise and psychological counseling are roughly equal in their benefits for cancer-related fatigue," Courneya, who wasn't involved in the study, added by email. "And both appear superior to current pharmaceutical treatments."

Ten nutrition mistakes even really healthy people make

-You add whole flaxseeds to your breakfast
Flaxseeds are filled with omega-3 fats, fibre and lignans (antioxidants), which all benefit heart health. But whole flaxseeds may pass through the intestines undigested, which means you'll miss out on the health benefits inside the seed. Buy ground flax seeds instead, or put them in a coffee or spice grinder.
-You blend a nutritious smoothie, but it's a calorie bomb
It's easy to toss a combination of superfoods into a blender. Blueberries, cashew butter, chia, kale, bananas and coconut milk sound like a dreamy breakfast elixir, but these concoctions can quickly become calorie bombs. Keep smoothies in the 300-calorie range by serving smaller portions (about 8-12 ounces), using more vegetables than fruit, and by going easy on the high-calorie nuts and seeds. -You take your supplements with coffee Caffeine from coffee can hinder your body's ability to absorb some of the vitamins and minerals in your supplements, including calcium, iron, B-vitamins and vitamin D. And it's not just coffee - beverages such as tea and cola contain caffeine, too. Enjoy your coffee about an hour before taking your supplements, and swallow pills with water instead.

- You use regular canned beans for your meatless meals
Beans are an amazing source of fibre and protein, but canned varieties may have close to 1,000 mg of sodium per cup - that's two-thirds of what you need in an entire day! Look for cans that say "no-salt-added" or "low-sodium." If you can't find them, drain and rinse your canned beans, which will eliminate about 40 per cent of the sodium. - To cut back on sugar, you cut out fruit The top source of sugar in many people's diets is sweetened beverages, not fruit. Sugary soft drinks have no beneficial nutrients, while fruit has fibre, vitamins and protective antioxidants. Plus, we don't tend to overeat fruit, but do tend to drink too much soda. Consider how much easier it is to down a 600mL soft drink, as opposed to eating six bananas at one time. Both pack 16 teaspoons of sugar. Choose fruit and skip the soft drink.

- You trust claims like 'low-fat' and 'sugar-free'
 For many years, we've relied on label claims that tell us what our food doesn't contain - fat, sugar, gluten.It's more important to look at what the food does contain. Ultra-processed foods may be fat-free or sugar-free, but also loaded with preservatives or refined ingredients. Read ingredient lists and choose foods that are as close to nature as possible.

 - You drink almond milk for calcium but don't shake the carton first
Milk alternatives made from soy, almonds, cashews, rice, etc. are often fortified with calcium and vitamin D. But the added nutrients don't stay in the liquid very well, and tend to sink to the bottom of the container. If you drink without shaking first, you can't reap the benefits of the added vitamins and minerals. Shake well before serving.

- You skip the dressing on salad Vegetables contain fat-soluble vitamins A, E and K, and a host of antioxidants that require fat to be absorbed. If you skip the oil and vinegar, you miss out on key nutrients from the salad. Serve your greens with oil-based dressing, nuts, seeds or avocado to dramatically boost your body's ability to soak up the veggies' beneficial nutrients.

- You miss out on probiotics by buying the wrong type of yoghurt
Yoghurt is fermented milk, and fermented foods contain probiotics. So, logic would dictate that all yoghurts are probiotic-rich, but unfortunately that's not the case. If yoghurt has been heated or pasteurised, probiotics are destroyed and may not be added back in. Look for the words "live active cultures," or check ingredient lists for names of specific probiotics (lactobacillus acidophilus, L bulgaricus, etc.) to ensure you're getting these beneficial bacteria, which aid digestion and support the immune system.

- You refuel with sports drinks
Sports drinks are meant to replace fluid and electrolytes that are lost when you sweat excessively, and are suitable after endurance sports like a soccer game or marathon. But the extra sugar and salt in sports drinks are not needed for casual exercise with minimal perspiration. After a stroll, hydrating with water is the best choice.

Thursday, March 9, 2017

Cardio vs. weights: Which is actually better for weight loss?

For decades, conventional wisdom (and Jane Fonda) said cardio was the best exercise for weight loss. Then strength training muscled its way into the spotlight as the must-do move for revving your metabolism and losing weight in your sleep, prompting many exercise enthusiasts to join #TeamNoCardio.

So a few years ago, Duke University researchers took to the lab and conducted the largest study of its kind to compare the two and get an answer once and for all. After 8 months of tracking 119 overweight and previously sedentary volunteers while they performed resistance training, aerobic exercise, or a combination of the two, the clear winner was ... aerobic exercise. By a lot. The cardio group lost about 4 pounds while their resistance training peers gained two. Yes, the weight gain was attributed to added lean mass.

However, that muscle mass didn't lead to any meaningful fat loss over the course of the study. In fact, the aerobics only group shed more than 3½ pounds of fat while the lifters didn't lose a single pound despite the fact that they actually exercised 47 more minutes each week than the cardio group. Not surprisingly, the cardio-plus-resistance group improved their body composition best -- losing the most fat while adding some lean mass.

But they also spent twice as much time in the gym. It's simple math, says study co-author Cris Slentz, PhD, assistant professor of medicine at Duke University. "Minute per minute, cardio burns more calories, so it works best for reducing fat mass and body mass." That's not to say that you shouldn't lift weights, especially as you get older and start losing muscle mass, he notes. "Resistance training is important for maintaining lean body mass, strength and function, and being functionally fit is important for daily living no matter what your size."

For the biggest fitness gain/weight loss bang for your exercise buck, combine the two, doing your strength training first and finishing off with your cardio. An American Council on Exercise study on exercise sequencing found that your heart rate is higher -- by about 12 beats per minute -- during your cardio bout when you've lifted weights beforehand. That means more calories burned. It's also important to remember one essential fact about exercise and weight loss, says Slentz. "Exercise by itself will not lead to big weight loss.

What and how much you eat has a far greater impact on how much weight you lose," he says. That's because it's far easier to take in less energy (calories) than it is to burn significant amounts and it's very easy to cancel out the few hundred calories you've burned working out with just one snack. Where exercise appears to matter most is for preventing weight gain, or for keeping off pounds once you've lost weight, says Slentz. "Exercise seems to work best for body weight control," he says. The National Weight Control Registry, which since 1994 has tracked more than 10,000 people who shed an average of 66 pounds and kept it off for at least five years, would agree. Ninety percent of successful weight loss maintainers exercise for about an hour a day and their activity of choice is cardio, simply walking.

Wednesday, March 8, 2017

Why men should take note of lymphedema

An uncomfortable swelling, lymphedema can develop after any surgery that removes or blocks lymph nodes or if radiation damages the superficial lymphatics. When lymph fluid cannot drain, it collects under the skin and in the soft tissues of the body, making the affected area feel heavy, tight and painful, among other symptoms. The chronic side effect can affect both women and men, though men sometimes need a push to be proactive. “There’s some extra effort involved in treating or educating men with lymphedema, since an important goal is to reduce the severity of future lymphedema episodes,” says Katherine Konosky, an occupational therapy clinical specialist at the University of Michigan. Konosky, whose team offers a monthly lymphedema education class at U-M’s Comprehensive Cancer Center, spoke more about the condition.

Does lymphedema treatment differ by gender?

Konosky: There’s a stereotype that only women with breast cancer develop lymphedema, but that’s not true. Anatomically, the lymphatic system is not significantly different between men and women. There’s no difference between men with lymphedema and women with lymphedema. Whether by individual appointment or in class, all our lymphedema patients learn about skin care; lymphatic drainage through massage; compression and stretching; and how to manage symptoms at home.

What kinds of cancer surgeries might cause lymphedema?

Konosky: Surgery for prostate cancer is the only one that’s gender-specific. Otherwise, it’s the same as for women: treatment for cancers of the head/neck, breast, bladder or kidney, liver or pancreas, parts of the digestive system — really, any cancer treatment in which lymph nodes are removed or the flow of lymphatic fluid has been damaged or blocked.

Can you deduce one’s chances of developing lymphedema?

Konosky: It depends on the type of surgery. For example, about 16 percent of melanoma patients develop lymphedema, and roughly 10 percent of genitourinary patients will experience lymphedema. Patients’ individual risk factors might also make them more susceptible. These can include: An extensive surgery Whether the patient had radiation treatment and to what extent the lymph nodes were targeted Whether the wound took more time than usual to heal Whether the tumor was obstructing the lymph system prior to surgery Scarring from the surgery (scar tissue can act as a barrier to the lymph system) A pre-existing condition such as diabetes, thyroid disease or obesity Stress Venous disease in a patient’s legs prior to inguinal (groin area) lymph-node removal

Do male patients address a lymphedema diagnosis differently than women?

Konosky: Men seem more concerned about what’s going on right now and less concerned about factors affecting the future. I had one male patient who was worried about his leg bandages falling down when he walked, so he duct-taped them in place. That’s concern for the present. In contrast, I don’t think I’ve ever had a male patient say that he typically takes extra care when doing something rough to cover and protect the limb with lymphedema. That would demonstrate concern for the future.

What wellness tips do patients, regardless of gender, need to know?

Konosky: It’s important for any lymphedema patient to understand and adopt these elements of self-care: Try to minimize skin or tissue trauma to the involved limb. Set a goal to maintain your ideal body weight. Modify eating habits to lower salt intake and avoid preservatives and artificial sweeteners. Stay hydrated by drinking plenty of water. Aim for an active lifestyle; movement stimulates the lymphatic system. Get screened before starting an exercise or weightlifting program; monitor for swelling or pain and modify the routine if needed.

Tuesday, March 7, 2017

Soy Tied To Longer Life After Breast Cancer

Eating more soy may be tied to better survival odds for many women with breast cancer and may not be harmful for patients treated with hormones, a new study suggests. Previous nutrition research has linked soy to a longer life, but prior studies have also suggested soy may help tumors spread by making hormone-based cancer treatments, or endocrine therapy, less effective.

For the current study, researchers examined data on 6,235 U.S. and Canadian women with breast cancer. More than half of the women were followed for at least nine years. During the course of the study, women who ate the most foods containing soy were 21 percent less likely to die than individuals who consumed the smallest amounts of soy. “All women or all breast cancer survivors can add soy as a component of a healthy diet,” said lead study author Dr. Fang Fang Zhang, a nutrition and science policy researcher at Tufts University in Boston.

The study focused on isoflavone, a compound in soybeans that can be found in foods like tofu, miso, edamame and soy milk. Isoflavone is in a family of plant compounds known as phytoestrogens that are chemically and structurally similar to the female sex hormone estrogen. Researchers found the strongest link between soy and survival for women with certain aggressive forms of breast cancer that can’t be treated with hormones. They didn’t see a link between soy consumption and longevity for women with tumors that depend on estrogen to grow or women receiving endocrine therapy.

“Our findings, taken together, indicate that soy food consumption does not have a harmful effect for women treated with endocrine therapies, but the benefit may be limited to women with negative tumor hormone receptors or those who were not treated with endocrine therapies,” Zhang added by email. For the study, researchers examined data from dietary questionnaires for women diagnosed with breast cancer from 1996 to 2011. They excluded women who died within one year of completing the first questionnaire. At the start, women were 52 years old on average and most had at least some education beyond high school. About 47 percent took hormone therapy for tumors.

On average, women consumed 1.8 milligrams of isoflavone daily, roughly the amount in one ounce of soy cheese and far less than a 3-ounce serving of tofu or a half-cup portion of edamame. During the study, 1,224 women died. Overall, women with the highest quartile of dietary isoflavone intake, an average of at least 1.5 milligrams a day, were 21 percent less likely to die than women in the lowest quartile who got less than 0.3 milligrams a day, researchers report in Cancer. For women with tumors not fueled by hormones, the highest amount of isoflavone intake was tied to 51 percent lower odds of death from all causes. Among women who didn’t receive hormone therapy, the highest level of dietary isoflavone was associated with 32 percent lower odds of death from all causes. One limitation of the study is that women who ate more foods with soy tended to be more affluent and educated, with healthier lifestyles, making it possible that other factors beyond dietary isoflavone influences longevity, the authors note.

Researchers also lacked data on the type and length of hormone therapy for women who received this treatment, which could also impact survival odds. Still, the findings build on previous research in Asia that linked high dietary soy intake to a lower risk of developing breast cancer, said Dr. Omer Kucuk, a researcher at the Winship Cancer Institute of Emory University in Atlanta. “It is not surprising that this study showed women in North America also benefit from soy intake with reduced mortality from breast cancer while on treatment,” Kucuk, author of an accompanying editorial, said by email. “Up until now physicians generally discouraged their breast cancer patients from eating soy foods because of potential harm,” Kucuk said. “We can now encourage women with breast cancer to eat soy foods because it is safe and it will likely improve their survival.”