Nighttime Light Exposure: Does It Increase Your Risk of Breast Cancer?

Women who live in areas with higher levels of outdoor light at night may be at higher risk for breast cancer than those living in areas with lower levels, according to a large long-term study from the Harvard T.H. Chan School of Public Health. The link was stronger among women who worked night shifts.

 

Background: Previous studies have suggested that exposure to light at night may lead to decreased levels of the hormone melatonin, which in turn can disrupt circadian rhythms – out internal “clocks” that regulate sleepiness and alertness. As a result, your risk of breast cancer may increase.

The Study: In the most comprehensive study to date (investigating possible links between  outdoor light at night and breast cancer, researchers examined data from nearly 110,000 women enrolled in the Nurses’ Health Study II from 1989-2013. The researchers linked data from satellite images of earth taken at nighttime to residential addresses for each study participant, and also considered the influence of night shift work. The study also factored in detailed information on a variety of health and socioeconomic factors among participants.

Results: Women exposed to the highest levels of outdoor light at night — those in the top fifth — had an estimated 1.14-times increased risk of breast cancer during the study period, as compared with women in the bottom fifth of exposure. As levels of outdoor light at night increased, so did breast cancer rates. The association between outdoor light at night and breast cancer was found only among women who were premenopausal and those who were current or past smokers. In addition, the link was stronger among women who worked night shifts, suggesting that exposure to light at night and night shift work contribute jointly to breast cancer risk, possibly through mechanisms involving circadian disruption.

 

My Take: While provocative and consistent with historic studies, there are many potential variables for which the investigators did not control. Still, while we need confirmatory studies, this may be a caution regarding night exposure. For my patients, this typically means limiting blue light exposure in the hour before bedtime. Watch out for those computer screens, cell phones, and televisions! I’m Dr. Michael Hunter.

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The small print: The material presented herein is informational only, and is not designed to provide specific guidance for an individual. Please check with a valued health care provider with any questions or concerns. As for me, I am a Harvard- , Yale- and UPenn-educated radiation oncologist, and I practice in the Seattle, WA (USA) area. I feel genuinely privileged to be able to share with you. If you enjoyed today’s offering, please consider clicking the follow button at the bottom of this page.

And, one more thing: NEW free apps for Android and iOS (Apple): In apps, search My Breast Cancer by Michael Hunter.

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Reference: Peter James, Kimberly A. Bertrand, Jaime E. Hart, Eva Schernhammer, Rulla M. Tamimi, Francine Laden. Outdoor Light at Night and Breast Cancer Incidence in the Nurses’ Health Study II. Environmental Health Perspectives, 2017 DOI: 10.1289/EHP935

 

Alternative Medicine for Cancer Ups Death Risk

Researchers from the Yale Cancer Center (USA) found that reject conventional medicine (for a potentially curable cancer) in favor of alternative treatments have a 2.5-fold higher risk for death.

 

Complementary versus alternative: If a non-mainstream practice is used together with conventional medicine, it is considered “Complementary.” If a non-mainstream practice is used inlace of conventional medicine, it is considered “alternative.” Today, we are addressing the latter. In my practice, we often bring conventional and complementary approaches in a coordinated way, an approach known as integrative medicine.

The Study: Researchers examined records (2004-2013) in National Cancer Database (USA) to find 280 patients with early-stage cancer (breast, prostate, lung, or colorectal) whose treatment was coded as “other-unproven: cancer treatment administered by non-medical personnel.” They then matched the alternative medicine group to 560 patients with the same types of cancer who received conventional treatments.

The Findings: Alternative medicine use was associated with a nearly 6-fold increased risk of death among patients with breast cancer. For those with colorectal cancer, the risk increased by a factor of 4.5, and among patients with lung cancer, the risk of death doubled. The risk among prostate cancers did not differ between the conventional and alternative treatment groups. The last is not a surprise, given the long natural history of prostate cancer and the short median follow-up of this study.

I’m Dr. Michael Hunter.

_________________________

The small print: The material presented herein is informational only, and is not designed to provide specific guidance for an individual. Please check with a valued health care provider with any questions or concerns. As for me, I am a Harvard- , Yale- and UPenn-educated radiation oncologist, and I practice in the Seattle, WA (USA) area. I feel genuinely privileged to be able to share with you. If you enjoyed today’s offering, please consider clicking the follow button at the bottom of this page.

And, one more thing: NEW free apps for Android and iOS (Apple): In apps, search My Breast Cancer by Michael Hunter.


Reference: This new study was published online in the Journal of the National Cancer Institute.

Poor adolescent diet associated with premenopausal breast cancer

“During adolescence and early adulthood, when the mammary gland is rapidly developing and is therefore particularly susceptible to lifestyle factors, it is important to consume a diet rich in vegetables, fruit, whole grains, nuts, seeds, and legumes and to avoid soda consumption and a high intake of sugar, refined carbohydrates, and red and processed meats.”

– lead author Karin B. Michels, ScD, PhD, professor and chair of the Department of Epidemiology at the UCLA Fielding School of Public Health, Los Angeles

Key points: Women who consumed a diet associated with chronic inflammation  as adolescents or young adults appear to have a higher risk of developing premenopausal breast cancer, as compared with those who had a diet not linked to inflammation.

Background: Researchers used data from 45,204 women in the Nurses’ Health Study II who had completed a food frequency questionnaire in 1998, when they were ages 33 to 52, about their diet during high School. The investigators then assed adult diet by first using a food frequency questionnaire in 1991, when participants were ages 27 to 44, and then every 4 years thereafter. They gave each woman’s diet an inflammatory score using a previously method that links diet with inflammatory markers in the blood.

During 22 years of follow-up, 870 of the women who completed the high school food frequency questionnaire were diagnosed with premenopausal breast cancer and 490 were diagnosed with postmenopausal breast cancer. When women were divided into five groups based on the inflammatory score of their adolescent diet, those in the highest score group had a 35 percent higher risk for premenopausal breast cancer relative to those in the lowest score group. When the same analysis was done based on early adulthood diet, those in the highest inflammatory score group had a 41 percent higher risk for premenopausal breast cancer relative to those in the lowest score group.

I’m Michael Hunter, the Breast Cancer Doctor.

Immunotherapy for Cancer

The latest approval of a cancer drug by the US Food and Drug Administration (FDA) changes the paradigm of cancer treatment — the new indication specifies a genetic defect without any mention of tumor types. It allows the drug to be used in any cancer that harbors the specified genetic defect, wherever the tumor appears in the body.

What: Historically, the US Food and Drug Administration (FDA) has approved cancer treatments based on where in the body the cancer started — for example, prostate or breast cancers. For the first time, the FDA approved a drug based on a tumor’s biomarker without regard to the tumor’s original location.

Details: The new approval is for the immunotherapy pembrolizumab (Keytruda, Merck & Co), which is already approved for use in several different tumor types, including melanoma and lung cancer. But this latest approval covers the use of pembrolizumab in tumors that have microsatellite instability-high (MSI-H) or are mismatch repair deficient (dMMR). These defects are found most commonly in colorectal, endometrial, and gastrointestinal cancers but also less commonly appear in cancers arising in the breast, prostate, bladder, thyroid gland, and other places, the agency notes.

Microsatellite instability & immunotherapy: It’s not just colorectal cancer: The results from that trial showed that patients with colorectal cancer with normal DNA repair (microsatellite stable) had zero response to pembrolizumab, whereas those with MSI and deficient DNA repair had a 50% response rate, she said. In addition, about 20% had stable disease. This is much higher than has been seen with immunotherapy in other tumor types, where fewer than 20% patients respond. But the trial also included patients with any solid tumor and MSI, and these patients also showed the 50% response rate and 20% stable disease results.

Downsides: Common side effects of pembrolizumab include fatigue, itchiness, diarrhea, decreased appetite, rash, fever, cough, dyspnea, musculoskeletal pain, constipation, and nausea. The drugs can also cause serious immune-mediated side effects, including lung, liver, kidney, or colon inflammation, endocrine problems.

Action point: All patients with advanced cancer who have had at least one standard therapy should be tested to see if their tumor harbors these genetic defects.

I’m Dr. Michael Hunter.

http://www.medscape.com/viewarticle/880537

Should doctors prescribe exercise?

“Although the data vary by different cancer types, there is a consistent trend suggesting that moderate daily exercise has a beneficial effect on preventing certain cancers. If you are a reasonably healthy adult, your should exercise regularly.” 

Let’s look at the relationship of exercise and selected cancers. The American Society of Clinical Oncology (ASCO) has done a nice job of summarizing:

Breast Cancer

While the amount of risk reduction varies among studies (20-80%), most suggest that 30 to 60 minutes of moderate to high-intensity exercise per day lowers breast cancer risk. Women who are physically active throughout their life appear to benefit the most, but those who increase physical activity after menopause also fare better than inactive women.1

Colon Cancer

Research suggests that people who increase their physical activity can lower the chance of developing colon cancer by 30 to 40% relative to sedentary adults.1,2 A decrease in colon cancer risk can be achieved regardless of body mass index (BMI) and people who are most active benefit the most. There is insufficient evidence of a protective effect of physical activity on the risk of rectal cancer (a protective effect was seen in some case-control studies, but not in cohort studies).3

Endometrial, Lung and Ovarian Cancer

A handful of studies have suggested that women who are physically active have a 20-40% reduced risk of endometrial cancer compared to those who don’t exercise.1 Higher levels of physical activity seem to also protect against lung cancer (up to 20% reduction in risk), particularly among men.1Although less consistent, research suggests that physical activity possibly reduces the risk of ovarian and prostate cancer.

What about Other Cancers?

While observational data on the benefits of exercise for prevention of the types of cancers listed above are fairly consistent, evidence of the effects of exercise on prevention of any other type of cancer either is either insufficient or inconsistent.2,4

Prostate Cancer

Prostate cancer is one disease in which the data are not consistent, however prostate cancer is a heterogeneous disease and risk factor associations for total non-aggressive disease are different from aggressive / lethal disease. Most population based studies show similar findings, with little effect of exercise on overall incidence of prostate cancer but lower risk of aggressive prostate cancers for those with the highest levels of VIGOROUS activity (rather than any type of activity). In the Health Professionals Follow-up Study men 65 years or older who engaged in vigorous physical activity, such as running, jogging, biking, swimming or tennis at least three hours per week  had a 67% lower risk of advanced prostate cancer and 74% lower risk of fatal prostate cancer.5

Conflicting data for other malignancies

For example, one recent study found no association between physical activity and risk of developing gastric, rectal, pancreatic, bladder, testicular, kidney and hematological cancers.4 In contrast, a pooled analysis of data from prospective trials with 1.4 million participants found that physical activity was linked to lower risk of 13 cancers: esophageal, lung, kidney, gastric, endometrial, myeloid leukemia, myeloma, colon, head and neck, rectal, bladder, and breast.6Interestingly, leisure-time physical activity was associated with a higher risk of melanoma (presumably due to time spent outdoors) and prostate cancer, although it is not clear from these data whether that association was with nonaggressive or aggressive prostate cancer.

While we wait for confirmation and clarity on the role of exercise in preventing all the 200+ types of cancer – should doctors prescribe exercise? The answer is simple: yes, because evidence of the protective role of exercise is already strong for some of the most common cancers.

References

  1. Lee I, Oguma Y. Physical activity. In: Schottenfeld D, Fraumeni JF, editors. Cancer Epidemiology and Prevention. 3rd ed. New York: Oxford University Press, 2006.
  2. Slattery, ML. Physical activity and colorectal cancer. Sports Medicine 2004; 34(4): 239–252.
  3. Pham NM, et al. Physical activity and colorectal cancer risk: an evaluation based on a systematic review of epidemiologic evidence among the Japanese population. Jpn J Clin Oncol. 2012 Jan;42(1):2-13.
  4. Friedenreich CM, Neilson HK, Lynch BM. Eur J Cancer. State of the epidemiological evidence on physical activity and cancer prevention. 2010 Sep;46(14):2593-604.
  5. Giovannucci E, Liu Y, Leitzmann MF, et al. A prospective study of physical activity and incident and fatal prostate cancer. Arch Intern Med. 2005; 165(9):1005-1010.
  6. Moore SC, Lee IM, Weiderpass E, et al. Association of Leisure-Time Physical Activity With Risk of 26 Types of Cancer in 1.44 Million Adults. JAMA Intern Med. 2016 Jun 1;176(6):816-25.
  7. http://www.asco.org/about-asco/press-center/asco-resources-media/cancer-perspectives/should-cancer-doctors-prescribe?et_cid=38723632&et_rid=463715101&linkid=Read+more

I’m Dr. Michael Hunter. Of course, the disclaimer: Do not begin an exercise program without input from an appropriate medical professional. Many can simply start with a brisk walk for 30 minutes daily, 5 days per week. Have a wonderful day!

Should doctors prescribe exercise?

young woman running city park

“Although the data vary by different cancer types, there is a consistent trend suggesting that moderate daily exercise has a beneficial effect on preventing certain cancers. If you are a reasonably healthy adult, your should exercise regularly.” 

Let’s look at the relationship of exercise and selected cancers. The American Society of Clinical Oncology (ASCO) has done a nice job of summarizing:

Breast Cancer

While the amount of risk reduction varies among studies (20-80%), most suggest that 30 to 60 minutes of moderate to high-intensity exercise per day lowers breast cancer risk. Women who are physically active throughout their life appear to benefit the most, but those who increase physical activity after menopause also fare better than inactive women.1

Colon Cancer

Research suggests that people who increase their physical activity can lower the chance of developing colon cancer by 30 to 40% relative to sedentary adults.1,2 A decrease in colon cancer risk can be achieved regardless of body mass index (BMI) and people who are most active benefit the most. There is insufficient evidence of a protective effect of physical activity on the risk of rectal cancer (a protective effect was seen in some case-control studies, but not in cohort studies).3

Endometrial, Lung and Ovarian Cancer

A handful of studies have suggested that women who are physically active have a 20-40% reduced risk of endometrial cancer compared to those who don’t exercise.1 Higher levels of physical activity seem to also protect against lung cancer (up to 20% reduction in risk), particularly among men.1Although less consistent, research suggests that physical activity possibly reduces the risk of ovarian and prostate cancer.

What about Other Cancers?

While observational data on the benefits of exercise for prevention of the types of cancers listed above are fairly consistent, evidence of the effects of exercise on prevention of any other type of cancer either is either insufficient or inconsistent.2,4

Prostate Cancer

Prostate cancer is one disease in which the data are not consistent, however prostate cancer is a heterogeneous disease and risk factor associations for total non-aggressive disease are different from aggressive / lethal disease. Most population based studies show similar findings, with little effect of exercise on overall incidence of prostate cancer but lower risk of aggressive prostate cancers for those with the highest levels of VIGOROUS activity (rather than any type of activity). In the Health Professionals Follow-up Study men 65 years or older who engaged in vigorous physical activity, such as running, jogging, biking, swimming or tennis at least three hours per week  had a 67% lower risk of advanced prostate cancer and 74% lower risk of fatal prostate cancer.5

Conflicting data for other malignancies

For example, one recent study found no association between physical activity and risk of developing gastric, rectal, pancreatic, bladder, testicular, kidney and hematological cancers.4 In contrast, a pooled analysis of data from prospective trials with 1.4 million participants found that physical activity was linked to lower risk of 13 cancers: esophageal, lung, kidney, gastric, endometrial, myeloid leukemia, myeloma, colon, head and neck, rectal, bladder, and breast.6Interestingly, leisure-time physical activity was associated with a higher risk of melanoma (presumably due to time spent outdoors) and prostate cancer, although it is not clear from these data whether that association was with nonaggressive or aggressive prostate cancer.

While we wait for confirmation and clarity on the role of exercise in preventing all the 200+ types of cancer – should doctors prescribe exercise? The answer is simple: yes, because evidence of the protective role of exercise is already strong for some of the most common cancers.

References

  1. Lee I, Oguma Y. Physical activity. In: Schottenfeld D, Fraumeni JF, editors. Cancer Epidemiology and Prevention. 3rd ed. New York: Oxford University Press, 2006.
  2. Slattery, ML. Physical activity and colorectal cancer. Sports Medicine 2004; 34(4): 239–252.
  3. Pham NM, et al. Physical activity and colorectal cancer risk: an evaluation based on a systematic review of epidemiologic evidence among the Japanese population. Jpn J Clin Oncol. 2012 Jan;42(1):2-13.
  4. Friedenreich CM, Neilson HK, Lynch BM. Eur J Cancer. State of the epidemiological evidence on physical activity and cancer prevention. 2010 Sep;46(14):2593-604.
  5. Giovannucci E, Liu Y, Leitzmann MF, et al. A prospective study of physical activity and incident and fatal prostate cancer. Arch Intern Med. 2005; 165(9):1005-1010.
  6. Moore SC, Lee IM, Weiderpass E, et al. Association of Leisure-Time Physical Activity With Risk of 26 Types of Cancer in 1.44 Million Adults. JAMA Intern Med. 2016 Jun 1;176(6):816-25.
  7. http://www.asco.org/about-asco/press-center/asco-resources-media/cancer-perspectives/should-cancer-doctors-prescribe?et_cid=38723632&et_rid=463715101&linkid=Read+more

 

I’m Dr. Michael Hunter. Of course, the disclaimer: Do not begin an exercise program without input from an appropriate medical professional. Many can simply start with a brisk walk for 30 minutes daily, 5 days per week. Have a wonderful day!

Cancer Risk Linked to DNA ‘Wormholes’

What You Need to Know: Single-letter genetic variations within parts of the genome once dismissed as ‘junk DNA’ can increase cancer risk through wormhole-like effects on far-off genes. Researchers found that DNA sequences within ‘gene deserts’ — so called because they are completely devoid of genes — can regulate gene activity elsewhere by forming DNA loops across relatively large distances.

The study, led by scientists at The Institute of Cancer Research, London, helps solve a mystery about how genetic variations in parts of the genome that don’t appear to be doing very much can increase cancer risk.

  • Researchers developed a new technique to study the looping interactions and discovered that single-letter DNA variations linked to the development of bowel cancer were found in regions of the genome involved in DNA looping.
  • Their study, published today in Nature Communications, is the first to look comprehensively at these DNA interactions specifically in bowel cancer cells, and has implications for the study of other complex genetic diseases.
  • The researchers developed a technique called Capture Hi-C to investigate long-range physical interactions between stretches of DNA — allowing them to look at how specific areas of chromosomes interact physically in more detail than ever before. Previous techniques used to investigate long-range DNA interactions were not sensitive enough to produce definitive results.

The researchers assessed 14 regions of DNA that contain single-letter variations previously linked to bowel cancer risk. They detected significant long-range interactions for all 14 regions, confirming their role in gene regulation. These interactions are important because they can control how genes behave, and alterations in gene behaviour can lead to cancer — in fact most genetic variations that have been linked to cancer risk are not in genes themselves, but in the areas of the genome that regulate them.

Study leader Professor Richard Houlston, Professor of Molecular and Population Genetics at The Institute of Cancer Research, London, said: “Our new technique shows that genetic variations are able to increase cancer risk through long-range looping interactions with cancer-causing genes elsewhere in the genome. It is sometimes described as analogous to a wormhole, where distortions in space and time could in theory bring together distant parts of the universe. Understanding how long-range genetic regulation works is crucial to understanding how cancer develops — and could be important in finding new ways to treat the disease in the future.”

Professor Paul Workman, Chief Executive of The Institute of Cancer Research, London, said: “A lot of the genetic variants already linked to cancer occur in gene deserts — often very long and quite mysterious DNA sequences that don’t actually contain ‘genes’, but which are involved in causing cancer in ways we do not yet fully understand.

“DNA looping is notoriously difficult to study but this research has taken an important step to understanding what genetic variations in DNA deserts might do to drive the development of bowel cancer.”

I’m Dr. Michael Hunter.


Story Source:

The above story is based on materials provided by Institute of Cancer Research. Note: Materials may be edited for content and length.


Journal Reference:

  1. Roland Jäger, Gabriele Migliorini, Marc Henrion, Radhika Kandaswamy, Helen E. Speedy, Andreas Heindl, Nicola Whiffin, Maria J. Carnicer, Laura Broome, Nicola Dryden, Takashi Nagano, Stefan Schoenfelder, Martin Enge, Yinyin Yuan, Jussi Taipale, Peter Fraser, Olivia Fletcher, Richard S. Houlston. Capture Hi-C identifies the chromatin interactome of colorectal cancer risk loci. Nature Communications, 2015; 6: 6178 DOI: 10.1038/ncomms7178

Cite This Page:

Institute of Cancer Research. “Cancer risk linked to DNA ‘wormholes’.” ScienceDaily. ScienceDaily, 19 February 2015. <www.sciencedaily.com/releases/2015/02/150219090349.htm>.