While there weren’t new blockbuster announcements for colorectal cancer this year at the American Society for Clinical Oncology’s (ASCO) Annual Meeting, there was plenty of focus on making what we already have work better and on choosing the patients who will benefit the most from treatments, as well as those who might not be helped at all. (Note, many of these issues will be discussed in detail on our upcoming patient webinar.)
- While adding oxaliplatin to 5-FU improves five year survival slightly for stage II colon cancer, it increases side effects, particularly tingling and numbness in the feet. An analysis of several NSABP trials found that two or three more stage II patients out of every 100 would be alive five years later if they were given oxaliplatin in addition to 5-FU than if they only got 5-FU. Risk of cancer returning was similar with an absolute improvement of 3 to 5 percent, depending on risk factors. Doctors and patients need to think about whether the small benefit is worth the risk of neuropathy that may become permanent.
- Two speakers at the Saturday colorectal cancer oral abstract session addressed adding oxaliplatin to 5-FU as part of pre-surgical chemoradiation treatment for rectal cancer. NSABP R-04 found that oxaliplatin did not help increase complete response rates, avoid colostomies, or downstage cancers. It did increase diarrhea significantly. On the other hand, early results from a German trial did find an increase in complete responses with oxaliplatin, and they didn’t see worse side effects.
- In the PRIME phase III clinical trial, patients receiving their first treatment for advanced colorectal cancer who had normal or wild-type KRAS genes in their tumor did better when Vectibix® (panitumumab) was added to FOLFOX chemotherapy. But those patients whose tumor KRAS was mutated actually did worse than patients who only got chemotherapy.
- Side effects, while difficult for patients, may predict better outcomes from treatment. Patients who got capecitabine as part of pre-surgical chemoradiation and developed hand-foot syndrome had fewer recurrences three years later and better survival at five years. In another study of breast, lung, and colorectal cancer, patients who got high blood pressure while on Avastin® (bevacizumab) lived longer and it took longer before their cancer got worse.