It's been another big year of cancer prevention news, and it started with a real splash way back in January with a headline-grabbing study in Science attributing most cases of cancer to simple "bad luck." Not surprisingly, we disagreed with that conclusion, and our post responding to the study - and the stories it generated - was one of the most popular on Cancer News in Context in 2015. Other popular posts ran the gamut of topics: from links between sugary sodas and earlier periods; to risk-reducing diet tips; to the on-going problem of tanning bed use by youth and young adults.
As we get set for another eventful year, here are our top 5 posts from 2015, in order of popularity:
- - - -
February 3, 2015
Study Finds Periods Start Earlier in Girls Who Drink a Lot of Sugary Drinks. What Does This Mean for Breast Cancer Risk?
A new study released last week in the journal Human Reproduction has found that regularly drinking sugar-sweetened beverages - like sodas and fruit drinks - may cause girls to start their menstrual periods at earlier ages.
The study, a spin off of the long-running Nurses' Health Study at Harvard University, followed around 5,000 9 - 14 year old girls for up to five years - tracking their food, beverage intake, and menstrual status along the way. Researchers found a distinct link between regularly drinking sugary beverages and the age periods started (technically called, menarche). Those girls who drank more than 1.5 servings of soda or fruit drink each day started their period on average at 12.8 years, about three months earlier than girls drinking 2 or fewer servings each week. Even after taking body mass index (BMI) into account, which is linked to age at menarche, the same general association remained.
So, what does this have to do with cancer?
There's increasingly good data that early life plays a particularly important role in later adult breast cancer risk, something we've certainly written about here on CNiC. This new study provides further evidence....
Setting the Record Straight on Cancer Prevention: Lifestyle Trumps "Bad Luck"
It's been hard to avoid the headlines this past week touting the conclusions of a new study in the journal Science that cancer is a disease largely caused by "bad luck." Some of these headlines have been sensationalized; some have been more measured. Together, they've seemed nearly ubiquitous. And in some ways that's been positive, demonstrating that cancer - and its causes and prevention - remain an important topic to both the public and the media.
Unfortunately, the conclusions of the paper - and the subsequent coverage they've received - seem to reach well beyond what the actually findings of the study support, and in doing so, have incorrectly called into question what decades of overwhelming evidence shows: that over half of all cancers - and up to three quarters of some cancers - could be prevented by regular screening and healthy lifestyle choices.
The new study by Johns Hopkins researchers Cristian Tomasetti and Bert Vogelstein gathered data on the number of stem cell divisions that occur in various tissues in the body and compared these data to annual incidence rates of cancers in those tissues. Stem cells divide to replace cells in tissue that die or are lost. This maintains the tissue. Some tissues need a lot of cell divisions for maintenance. Others need less. When cells divide, the DNA in cells also replicate and divide, opening up the chance for random mutations that could eventually lead to cancer.
The researchers found a strong correlation between tissues' number of stem cell divisions and cancer in those tissues, attributing 65% of cancers to these divisions, and the random DNA mutations that can occur with them.
While the study is well-designed and executed, it also has...
Bottom Line of New Study: Colon Cancer is Quite Preventable
A large proportion of colon cancer is preventable with healthy lifestyle choices, even without taking into account the benefits of screening. That's the finding in a new analysis from the large Nurses' Health Study released in print last week in Cancer Causes & Control. The analysis, done by researchers from Stanford and Harvard Universities, calculated the percentage of colon cancers in women that could be attributable to a combination of lifestyle choices that have been found in previous research to be established risk factors for the disease: overweight/obesity, lack of physical activity, alcohol intake, smoking, low multivitamin use, and low calcium intake.
Comparing women who had only one or none of these risk factors with women having two or more, the researchers found that 37 percent of colon cancer cases in women could be avoided through healthy lifestyle choices. This proportion was even higher when aspirin use was considered. Though not a lifestyle choice, per se, long term aspirin use has been shown in many well-designed studies to lower the risk of colon cancer. When aspirin use of just twice a week for six years or more was added to the analysis, the percentage of cancers estimated as preventable rose to 43 percent.
These percentages are quite significant and do not even take into account the further benefit of colon cancer screening, which in addition to catching cancer early can also prevent the disease by finding (and removing) pre-cancerous growths.
Preventing Skin Cancer: Tanning Beds Still Alluring, Still Very Risky
There was a nice piece in the New York Times this weekend on the risks of indoor tanning, particularly in youth. Focussing on the personal experiences of a handful of young women and their parents, it does a very good job highlighting the well-established risks of skin cancer and deadly melanoma, the continued allure of tanning, and some promising advances in tanning salon regulation and rates of tanning by youth.
We've written a number of posts over the years here on Cancer New in Context (see below) about the dangers of tanning beds and the need for better policies to curb their use and protect youth. So, it's good to see the topic continuing to gain traction both in terms of awareness and in the willingness of state and federal government to take important tax and regulatory action to try to maintain the recent downward trend in tanning bed use.
In many ways, it's similar to the concerted efforts that have helped curb tobacco use over the past 50 years, a similarity not lost on 22 year-old Westfield State University student, Elizabeth LaBak, who was highlighted in the Times article:
“The tanning thing is like the smoking thing,” she said. “Everyone used to smoke. And then they said, ‘You’ll die of lung cancer.’ That’s what’s happening to tanning.”
When it comes to cancer, there are few topics as supercharged as diet. A quick search of “diet and cancer” in Google News alone returns over 3 million stories. And yet, however large these numbers are, they don’t fully capture the passion that many people feel about the food/cancer link. There’s something special, elemental even, about making sure the food we eat is as safe and as healthy as possible – for us and for our loved ones.
Yet, however motivated people are to make healthy food choices, there are a lot of mixed signals out there on what to eat to lower cancer risk. Magazines and websites often tout “superfoods” and “cancer-busters” that rarely match up with official eating recommendations, and even these official recommendations seem to change month to month with the release of new – and often seemingly contradictory – study results.
Trying to decide what to eat can be an exercise in frustration, a sentiment captured perfectly in findings from a 2007 paper on public beliefs about cancer prevention. In this national sample survey, over 70 percent of respondents agreed with the statement that “there were so many recommendations about preventing cancer that it’s hard to know which ones to follow” (1).
The reality, though, is that when all the evidence on the links between diet and cancer are looked at together, clear and simple messages rise to the surface. These messages contain no “superfoods” or “cancer-busters” and, so, may not always lead the headlines. But what they may lack in headline-grabbing flash, they more than make up for by being recommendations based in solid science. And that’s really what matters.
Watch the calories
We see them listed everywhere and so have become inured to them in a way, but calories really matter when it comes to cancer risk. In fact, they’re probably the single most important aspect of diet when it comes to preventing cancer. Consistently eating too much can lead to weight problems. And, among other health risks, obesity is an established risk factor for at least eight different cancers and is responsible for 120,000 cases each year in the United States (2,3).
Over two-thirds of the nation is either overweight (BMI 25 – 29.9) or obese (BMI 30 or over), and studies consistently demonstrate that people have difficulty recognizing if they – or their children – are an unhealthy weight. Add to this the increasingly sedentary lifestyles that go along with modern society, and it takes a concerted effort by most people to moderate calories and keep weight in check over the course of their lives (4). These simple tips can help keep calories and weight in control:
Avoid sugary drinks, like sodas, energy drinks, and sports drinks. Even 100% juice should be kept to small amounts each day.
Focus on eating mostly plant-based foods, like whole grains, fruits, and vegetables.
Be a more mindful eater. Start with smaller portions, eat slowly, and try to eat only when truly hungry.
Fit physical activity into each day. More is almost always better, but any amount is better than none.
Weigh your self on most days. It’s easy, keeps surprise weight gain at bay, and helps you make diet/activity adjustments in a timely manner.
Limit food from animals You don’t need to go full vegetarian – unless you want to – but there’s compelling data that eating fewer animal-based foods can lower the risk of colon cancer, prostate cancer, and possibly breast cancer (5-7). Try to eat fewer than three servings of red or processed meat each week, and choose more plant-based sources of protein and fat, like nuts, beans, and vegetables.
Focus on fruits, vegetables, and whole grains The data linking fruits and vegetables as a whole with lower cancer risk...