Leonard Saltz: Novel Approaches to Colon Cancer, Behaviors That Impact Survival

It’s been years since a large portion of colon cancer patients have seen any innovations in treatment. However, there are dietary and physical behavioral changes individuals can make that positively impact colon cancer survival said Leonard Saltz, MD, executive director of Clinical Value and Sustainability, head of Colorectal Oncology Section, Memorial Sloan Kettering Cancer Center.

Transcript

Are there any novel approaches currently being taken in the treatment of colon cancer?

Colon cancer’s an area where we’re stalled, to be blunt. We haven’t had, in my opinion, a really important innovation for the majority of patients since 2003. So, we’ve been in a 15-year, kind of, stagnant period. The most important innovation in the last few years has been recognizing that the limited number of patients with mismatch repair deficit or high microsatellite instability tumors can benefit from PD-1 inhibitors and can benefit very substantially from them, whereas, the other patients with microsatellite stable or mismatch repair proficient disease do not benefit from those agents.

Now, the mismatch repair deficiency tumors, in general, are a favorable prognosis, which means that a lot of them don’t even become stage 4. So, when we look at the metastatic or stage 4 patients, who are mismatch repair deficient, its somewhere between 2% and 4% of the entire colorectal population. Important for those 2% to 4%, but it doesn’t help the rest.

What behaviors have you identified that impact colon cancer survival?

We published a number of articles on those topics, and a lot of this goes back to a clinical trial that I led a number of years ago, where we were looking at 2 different therapies for adjuvant treatment of stage 3 colon cancer. The trial was a negative trial. The experimental regimen was no better than the standard. But, my colleagues at Dana-Farber had attached a very detailed dietary and activity questionnaire to that study, and more than 900 patients filled it out, 3 months and 12 months after their survey. So, we were able to look back after 5 years or more, and look for correlations between who stayed cancer-free and who didn’t, and a number of very important aspects came out.

People who reported maintaining a high correlation with what the Harvard School of Public Health calls "the prudent diet," basically a pescatarian diet, vegetarian plus seafood with an emphasis on whole grain, low in animal fat, low in refined grain, low in sugar, did substantially better than people with a, what we’ve euphemistically called, a western diet, a junk food diet, essentially, high in refined carbohydrates and high in animal fat. We saw that people that got regular aerobic exercise had a substantial risk reduction compared to people that basically were bed to chair or sedentary, and we saw, within the dietary breakdown, certain correlations that were rather interesting.

Tree nuts were favorable, and it’s important to emphasize that does not include peanuts, which are not actually a nut; they’re a legume. High consumption of all the other nuts we think about, cashews, almonds, walnuts, pistachios, are correlated with favorable outcome. We think that means it’s a good idea to eat them, of course, it’s a retrospective observational study, so we don’t know.

To my great delight, we found that coffee was a good thing, and that, people who reported drinking 4 or more cups, and at the time we did a cup as a 6-ounce to 8-ounce cup of coffee, of caffeinated coffee a day had a meaningful risk reduction compared to non-coffee drinkers. And we found that dark flesh fish has a favorable prognostic factor. People eating frequent servings of tuna, mackerel, blue fish, salmon, fish that would be high in the kind of omega-3 oils that we think are helpful, also correlated with favorable outcome.