Adjuvant Chemotherapy May Confer Survival Benefit in Patients Older than 75 with Stage III Disease

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Because few people over 75 participate in clinical trials, it is unknown whether adjuvant chemotherapy could benefit this population. Faced with this gap in clinical trial evidence, researchers reviewed data from 5,489 patients ≥ 75 years with stage III colon cancer. The review suggests that patients over age 75 with surgically resected colon cancer may have a survival benefit from chemotherapy similar to that previously demonstrated for younger patients in randomized and observational studies.

The results were published in the Journal of Clinical Oncology. “From the perspective of a practicing clinician, these results suggest that consideration of adjuvant systemic therapy is absolutely warranted for patients older than 75 years,” the authors concluded.

“Of the 141,000 people diagnosed with colorectal cancer in the United States in 2011, 40% will be 75 years of age or older. Patients older than 75 years also account for half of colorectal cancer deaths. Despite this disproportionate burden, older patients are underrepresented in clinical trials of colorectal cancer chemotherapy,” the researchers noted.

Study Design

“To shed light on actual practice patterns and outcomes, we evaluated the effectiveness of any adjuvant chemotherapy for patients older than 75 years with stage III colon cancer and whether the addition of oxaliplatin provides additional survival benefit,” the researchers explained. Demographic, stage, treatment, and survival information were obtained from four data sets: SEER-Medicare, a linkage between the New York State Cancer Registry (NYSCR) and its Medicare programs, the National Comprehensive Cancer Network Outcomes (NCCN) Database, and the Cancer Care Outcomes Research and Surveillance Consortium (CanCORS).

The use of chemotherapy after resection of stage III cancer differed among cohorts, ranging from 42% in the SEER-Medicare group to 75% in the NCCN group. “As expected, the use of both any chemotherapy and oxaliplatin-containing regimens dropped off quickly with advancing age,” the investigators reported.

Chemotherapy-treated patients had much better survival than those not receiving chemotherapy after resection of stage III colon cancer. “Oxaliplatin offers no more than a small, incremental benefit,” the researchers added. A critical, unanswered question is how adjuvant therapy affects quality of life.

For more information on adjuvant therapy in older patients with colorectal cancer, see page 21.

Sanoff HK, et al: J Clin Oncol, June 4, 2012 (early release online).