Older patients with colon cancer able to tolerate adjuvant chemotherapy

WASHINGTON — Older people who undergo chemotherapy after surgery for colon cancer were not at a greater risk for adverse events compared with younger patients, according to the results of a recent study.

Moreover, older patients experienced fewer adverse events because they usually received shorter durations of less toxic chemotherapy, said Robert H. Fletcher, MD, MSc, professor emeritus at Harvard Medical School and adjunct professor of epidemiology and social medicine at the University of North Carolina.

The study was published in the cancer-themed issue of the Journal of the American Medical Association.

“What we’ve found is that, if you look at patients with the secondary problems physicians are worried about, they didn’t have more adverse events than younger patients,” Fletcher told HemOnc Today. “Certainly our data suggest that oncologists have overestimated the risk.”

Fletcher and colleagues analyzed the use of adjuvant chemotherapy and resultant adverse events by age groups in 675 patients diagnosed with stage III colon cancer treated with surgical resection from 2003 through 2005. There were 202 patients who were aged 75 years or older in the study, half of whom also underwent chemotherapy. By comparison, 87% of patients aged 18 to 74 years received adjuvant chemotherapy.

Fletcher said although patients aged 65 years and older were more likely than younger patients to discontinue chemotherapy, patients who had chemotherapy had fewer health problems by all measures. In addition, patients older than 75 years were less likely to receive oxaliplatin (14%) compared with younger patients (44%).

Overall, 24% of patients reported at least one late adverse event. Adverse events were twice as common in patients who underwent chemotherapy. However, patients 75 years and older who had chemotherapy were less likely to experience toxicity compared with younger patients who underwent chemotherapy, with an adjusted rate of 0.28 for patients aged 75 years and older vs. 0.35 for those aged 18 to 54 years.

“Some people clearly shouldn’t receive adjuvant chemotherapy, but that’s just a tiny proportion of people aged 65 to 75,” Fletcher said. “Our data suggest more patients should be considered for adjuvant chemotherapy. We need to find a way to determine what proportion of patients we can treat safely.” – by Jason Harris

Kahn K. JAMA. 2010;303:1037-1045.