Cautious Optimism for Survivorship Findings at AICR Afternoon Session

Moving more every day in any way is an important component to cancer survival.

At the Diet, Physical Activity and Survivorship session of AICR’s annual meeting, leading researchers pointed to the latest developments in lifestyle changes that might affect risk and death from major cancers. Catherine M. Alfano of the National Cancer Institute stressed the desire of cancer survivors, now numbering more than 12 million in the US, to “take control and actively participate” in beating cancer.

In breast cancer, physical activity has been studied most and found to have an impact on preventing recurrence and improving quality of life, as well as reducing negative side-effects of treatment.

Human trials looking at the impact of physical activity, diet and obesity on other kinds of cancers are sorely needed — as borne out by evidence presented by Jeffrey Meyerhardt, Ph.D, of Dana-Farber Cancer Institute in Boston, who noted that studies linking physical activity with preventing colon cancer have shown clear results, but design of studies on survivors have varied.

Finding evidence on recurrence and mortality is more complex, Dr. Meyerhardt said, such as in looking into the various stages of colon cancer diagnosis, so these studies must be large and long-term, accumulating data over decades.

Prostate cancer and physical activity also has not been adequately studied, although presenter Edward Giovanucci, MD, of Harvard University said that being active before diagnosis is best, and that vigorous activity seemed to help survivors in the later stages of prostate cancer. He noted that brisk walking (3 miles an hour or more) for at least 7 hours per week did seem to have a positive effect in a small study of prostate cancer survivors. As for obesity, studies so far do not show an effect on survival from prostate cancer, but they may affect screening and treatment effectiveness, which may in turn affect survival of this cancer. A low-fat diet also seems to help survival rates.

The presenters emphasized the many health benefits of a physically active and prudent-diet lifestyle besides the likely cancer prevention and survival benefits, including lower risk for diabetes, heart disease and other chronic health problems — in other words it’s smart to make healthy changes while we are still healthy so that even after a cancer diagnosis, we are more likely to survive.

From the AICR Research Conference: A Short-Term Benefit to Calorie Restriction?

Aging expert Dr. Stephen Austad of the University of Texas Health Science Center kicked off our research conference’s plenary session on diet, activity, aging and cancer this morning with an overview of the history of the study of calorie restriction (generally defined as a 30 to 40 percent fewer calories without nutrient deficiency).

The fact that calorie restriction has been linked to longevity and cancer prevention in particular has been established for decades in animal models. Dr. Austad began by reviewing that literature, and highlighting more recent work which suggests that the protective effect of calorie restriction on lifespan in these animal models seems to be growing less clear-cut: work with wild mice strongly suggests that genetics play a role in determining whether calorie restriction increases or decreases longevity.

Interestingly, however, the effect of calorie restriction on cancer prevention seems just as strong in wild mice as it is in lab mice, suggesting that diet’s protective role against cancer doesn’t strongly depend on genetics.

But in addition to calorie restriction’s long-term effects, Dr. Austad presented some data on a surprising short-term effect his team has uncovered — and posited an intriguing theory.

He’s found that short-term (1-2 day) fasting of mice seems to increase their ability to defend against some common toxins, including some chemical carcinogens.  He offered an evolutionary thesis: “When you’re starving, you become less choosy about what you eat,” he said. “If you’re a mouse, and you can’t get seeds, you might turn to plants that contain toxins, or spoiled and bacteria-laden foods.  Nature may have installed a mechanism to bolster the body’s defenses in times of extreme fasting.”

It’s preliminary research, and it’s certainly no reason to starve yourself before travelling to a malaria zone or anything, but it’s a fascinating theory, and one that Dr. Austad hopes to pursue in the future.

Broccoli Sprouts: Extending Cell Life; Delaying Cancer?

AICR’s “It’s Never Too Late” campaign kicked off today, and it was launched in parallel with presentations at our Annual Research Conference on the latest findings in the field of lifestyle links with aging and cancer. The topic is the opening session of the conference and Trygve Tollefsbol, PhD, of the University of Alabama, just presented on how dietary intake – or restriction –influence genes related to both aging and cancer.

Dr. Tollefsbol’s lab is looking at how plant compounds influence cells and for over a decade he has focused on cell’s epigenetic changes, the turning “on” and “off” of genes. Epigenetic is not about what we inherit, but about how what a person eats and other life choices can affect our genes and thereby, affect aging and diseases such as cancer.

Here, Tollefsbol presented his research showing that sulforaphane, a compound in cruciferous vegetables, leads to epigenetic changes that lead to reductions in the amount of telomerase, a protein that produces telomeres. Most cancer cells need telomerase to multiply. Most healthy cells don’t have telomerase. (Telomerase produces telomeres, strips of DNA on the tips of our cells that shorten as we age.)

The amount of sulforaphane Dr. Tollefsbol used in the studies equaled about one cup of broccoli sprouts.

There will be more on his research and cruciferous vegetable research later in the conference. Stay tuned.