Outcomes of elderly patients with node-positive colon cancer: A multi-center population-based cohort study.
Authors: Carl Pinter, Shubham Sharma, Aunum Abid, Osama Ahmed, Haji I. Chalchal, Dorie-Anna Dueck, Dilip Gill, Joshua Gitlin, Branawan Gowrishankar, Peter Graham, Kamal Haider, Kimberly Marie Hagel, Mussawar Iqbal, Rani Kanthan, Selliah C. Kanthan, Duc Le, Jocelyn Moore, Shazia Mahmood, Adnan Zaidi, Shahid Ahmed
Journal: Journal of Clinical Oncology (2024)

33 Background: Patients with stage III colon cancer are at high risk of recurrent disease. In this large population based cohort study we examined prognostic significance of chemotherapy and other clinical, pathological &amp; contextual variables that are associated with inferior outcomes in elderly patients with stage III colon cancer. Methods: Patients ≥ 70 years with stage III colon cancer diagnosed in Saskatchewan, a Canadian province, and underwent resection of the primary tumor during 2012-2018 were evaluated. A Cox proportional multivariate survival analysis was performed to determine factors correlated with overall survival (OS) and disease-free survival (DFS). Results: 404 eligible patients with median age of 79 yrs &amp; M:F of 1:1 were identified. 48% were ≥80 years, 60% were rural resident, 66% had ≥ 1 major comorbid illness, 34% had WHO performance status &gt;1, 14% has an ostomy formation, 46% had a T4 or N2 high-risk disease, and 50% had node positive to node harvested (NPNH) ratio of &gt;0.1. 43% patients received adjuvant chemotherapy. Median time to start chemo was 9 weeks. Patients who did not receive adjuvant chemotherapy were significantly older, had low performance status or experienced high rate of post-operative complications, high serum creatinine, low albumin, anemia, elevated WBC count and platelets. Median OS of all patients was 51 months (95%CI: 42.4-59.6), with estimated 5 &amp; 10-yr OS of 45% and 30%. Median DFS of entire cohort was 32 months (26.3-37.7) with 5 &amp; 10-yr DFS of 34% and 20%. Patients who received adjuvant chemotherapy had median OS of 106 months (83.8-128.5) vs. 30 months (23.4-36.6), p&lt;0.001 with 5 &amp; 10-yr OS of 64% and 49% vs. 31% and 19% (p&lt;0.001). Patients who received adjuvant chemotherapy had median DFS of 56 months (28.2-83.9) vs. 22 months (16.5-27.5), p&lt;0.001 with 5 &amp; 10-yr DFS of was 49% and 30% vs. 24% and 13% (p=&lt;0.001). The Cox-multivariate analysis revealed a past history of cancer, HR, 1.32 (1.03-1.72); ostomy, HR, 1.33 (1.02-1.74); NPNH ratio &gt;0.1, 1.34 (1.04-1.78); grade III tumor, 1.36 (1.04-1.78); WHO performance status &gt;1, HR, 1.38 (1.05-1.82); no adjuvant chemo, HR, 1.38 (1.03-1.85); high-risk stage III disease, HR, 1.39 (1.10-1.79), and baseline CEA &gt;5, HR, 1.75 (1.34-2.29), were independently correlated with DFS whereas past history of cancer, HR, 1.47 (1.12-1.94); ostomy, HR, 1.53 (1.16-2.03); NPNH ratio &gt;0.1, 1.51 (1.15-1.98); grade III tumor, 1.54 (1.16-2.04); WHO performance status &gt;1, HR, 1.42 (1.06-1.90); no adjuvant chemo, HR, 1.82 (1.32-2.50); high-risk stage III disease, HR, 1.60 (1.22-2.11), and CEA &gt;5, HR, 1.98 (1.50-2.61) were independently correlated with OS. Conclusions: In elderly patients with stage III colon cancer lack of adjuvant chemotherapy, poor performance status, T4 or N2 disease, grade III tumor, elevated baseline CEA, past history of a secondary cancer, elevate NPNH ratio &gt;0.1 and an ostomy formation correlate with inferior outcomes.