Adjuvant chemotherapy for colorectal cancer: role of specialized unit

AIM: to evaluate the rate and timeliness of adjuvant chemotherapy (ACT) in patients with stage II–III colon cancer (CC) after surgery in different medical units of the Arkhangelsk region and to assess its prognostic value.PATIENTS AND METHODS: all records on patients with CC after radical surgery in 2010–2021 were extracted from the Arkhangelsk Regional Cancer Registry (ARCR). Proportions of those who received ACT, the average waiting time for ACT and survival depending on the fact of ACT in specialized oncological unit (SOU), including the Arkhangelsk Clinical Oncology Dispensary (ACOD) and non-specialized medical units (NMU). Cancer-specific survival (CSS) was assessed. The hazard ratio (HR) of death from CC was estimated by Cox regression depending on receiving ACT and the waiting time for it.RESULTS: the database included 1032 cases (538 patients with stage III and 494 with stage II patients, who had unfavorable prognosis factors). No differences were found in ACT rate among patients with stage II CC. In stage III CC, ACT was performed in 73.5% of patients operated on in the SOU and 46.3% in NMU (p < 0.0001). The median waiting time for ACT after radical surgery in the SOU was 33.5 (17.0; 43.5) days, and 46.5 (31.0; 64.5) days in the NMUs, p < 0.0001. The five-year CSS of those who received ACT was 67,2% (95% confidence interval (CI): 60.8–72.9%), and 64.1% (95% CI: 58.8–68.1%) for those who did not receive ACT, p = 0.012. Five-year CSS after chemotherapy started within 4 weeks after radical surgery was 73.2%, for the gaps 5-8, 9–12 and more than 12 weeks 70.4%, 63.7%, and 35.4%, respectively, p = 0.002. In the adjusted model, the HR for death from ROC was 3-fold higher in patients receiving ACT at 12 + weeks (HR = 2.6 (95% CI: 1.31–5.14), p = 0.006) compared with the 0–4-week interval.CONCLUSION: the study revealed lower and later incidence of ACT in NMU affected worse survival.