Earlier initiation of adjuvant chemotherapy improved survival in rectal cancer
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Patients with rectal cancer who began adjuvant chemotherapy within 6 weeks of surgery demonstrated a significant survival benefit compared with those who started treatment later, according to study results.
Prior research has explored the effect of time to adjuvant chemotherapy on survival in patients with early-stage colon cancer, but the ideal time to adjuvant chemotherapy for patients with rectal cancer has not been established, according to background information provided by researchers.
Hagen Kennecke, MD, of the department of medical oncology at BC Cancer Agency in Vancouver, and colleagues evaluated data on 328 patients treated for stage II (25%) or stage III (75%) rectal cancer between 1999 and 2008. Median patient age was 61 years (range, 22-85), and 70% were men.
All patients received preoperative chemoradiation, and they underwent adjuvant chemotherapy at varying time points after surgery.
Researchers evaluated patients at four pre-determined time points: 4 weeks, 6 weeks, 8 weeks and 12 weeks post-surgery.
Median time to adjuvant chemotherapy was 7 weeks.
Results showed patients who began adjuvant chemotherapy within 6 weeks of surgery demonstrated significantly longer OS (HR=0.52; 95% CI, 0.31-0.9). Researchers observed no significant survival benefit among patients who began adjuvant chemotherapy 4, 8 or 12 weeks post surgery (P>.05).
Cut-point analysis showed the ideal time to adjuvant chemotherapy was 5.6 weeks. Patients who began treatment within that timeframe experienced significantly improved OS compared with those who began treatment >5.6 weeks after surgery (HR=0.42; 95% CI, 0.22-0.82).
In multivariate analysis adjusted for age, gender, ECOG performance status, disease stage, margin status and grade, the cut-point of 5.6 weeks remained a significant predictor for OS (P=.04).
Disclosure: See the full study for a list of the researchers’ relevant financial disclosures.