Suffering through cancer chemotherapy is worth it — when it helps patients live longer. But many patients end up with no real benefit from enduring chemo after surgical removal of a tumor. Going in, it's been hard to predict how much chemo will help prevent tumor recurrence or improve survival chances.
But now, a European study of lung cancer patients shows that cancers lacking a DNA-repairing protein are very sensitive to chemo. Patients whose tumors lack the gene for this protein do better after chemo; those whose tumors carry the gene get no additional benefit, the study found.
University of Paris researchers Ken A. Olaussen, Ph.D.; Jean-Charles Soria, M.D., Ph.D.; and colleagues report the findings in the Sept. 7 issue of The New England Journal of Medicine.
"We may have a tool that can distinguish between patients who can benefit from platinum-based chemotherapy and those who cannot benefit from such treatment," says Eddie Reed, M.D., director of the CDC's Division of Cancer Prevention and Control, in an editorial accompanying the European study.
Olaussen and colleagues analyzed data from a very large clinical trial looking at whether post-surgery chemo improved survival for non-small-cell lung cancer patients. It did — but only by about 4 percent.
As part of the study, the researchers collected 761 tumor samples. Less than half — 44 percent — carried a protein called ERCC1; the other 56 percent did not. ERCC1 has been a suspect in chemotherapy resistance because it repairs DNA. Platinum-based chemotherapy works by disrupting the cancer's DNA.
Sure enough, the researchers found that patients whose tumors did not carry ERCC1 had better odds for survival — about 14 months longer — if they underwent chemo. Five years after treatment, 47 percent of those who got chemo were still alive. The five-year survival rate was 39 percent among those who did not undergo chemo.
Chemo did not affect the survival of patients whose tumors carried ERCC1. However, in an interesting note, among patients who did not get chemo, ERCC1-positive patients survived longer than ERCC1-negative patients.
While the study was conducted in lung cancer patients, Olaussen and colleagues note that ERCC1 has been linked to chemo resistance in patients with other kinds of cancer, including stomach, ovarian, colon, and esophageal cancers.
SOURCES: Olaussen, K. The New England Journal of Medicine, Sept. 7, 2006; Vol, 355: pp. 983-991. Reed, E. The New England Journal of Medicine, Sept. 7, 2006; Vol. 355: pp. 1054-1055.
By Daniel DeNoon
Reviewed by Louise Chang