NEW YORK (Reuters Health) – After surgery for stage III colon cancer, adjuvant chemotherapy reduces the risk of distant recurrence by about half, and elderly patients benefit to a similar degree as younger ones, a Dutch population-based study indicates.

The decision to give adjuvant chemotherapy “should be based on a multidisciplinary and functional assessment of the patient, not on age,” the researchers conclude in their report.

Ms F. N. van Erning, with the Eindhoven Cancer Registry, and colleagues point out that while about half of patients with colon cancer are older than 70, relatively few are enrolled in clinical trials so it is not clear if they benefit from adjuvant chemotherapy in terms of distant recurrence risk. In fact, they add, the use of chemotherapy drops rapidly with increasing age.

To investigate further, the team analyzed data on 1291 patients with stage III colon cancer treated in clinical practice in the southern Netherlands between 2003 and 2008. Overall, 56% received adjuvant chemotherapy, 31% developed distant metastases, and 37% were 75 years of age or older, according to the August 8th online report in the Annals of Oncology.

In the total population, the use of adjuvant chemotherapy significantly reduced the risk of distant recurrence (hazard ratio, 0.55), the researchers found.

The analysis was repeated separately for patients younger than 75 and those 75 and older. The effect of adjuvant chemotherapy on recurrence risk was found to be similar in both age groups, with HRs of 0.50 and 0.57, respectively.

In a subsample of patients drawn for the total population who were matched by propensity score, recurrence risk remained significantly lower with adjuvant chemotherapy (HR, 0.46).

While acknowledging the limitations of the study, the authors conclude: “Distant recurrence risks at higher age definitely warrant consideration of adjuvant chemotherapy for elderly stage III colon cancer patients.”

However, they caution, “It remains important to realize that in certain circumstances, withholding adjuvant chemotherapy from elderly may be appropriate, for example in case of short life expectancy  (<1–2 years) or increased risk of serious side-effects.”

SOURCE: Reduced risk of distant recurrence after adjuvant chemotherapy in patients with stage III colon cancer aged 75 years or older
Ann Oncol 2013.