Effectiveness of combination of oxaliplatin in adjuvant chemotherapy for very high-risk stage II colorectal cancer: a cohort study

Keywords

colorectal neoplasm - adjuvant chemotherapy - progression free survival

Background: Colorectal cancer is the third most common neoplasm, being treatable and potentially curable if diagnosed early. Adjuvant chemotherapy with oxaliplatin is debated for patients with stage II colon cancer with poor prognostic features such as obstruction or perforation, stage T4, resection of less than 12 lymph nodes, unfavorable histology.

Objective: To evaluate the effectiveness of adding oxaliplatin to adjuvant chemotherapy in patients with stage IIA colorectal adenocarcinoma with less than 12 resected lymph nodes, IIB and IIC, given the controversy in the literature.

Methods: An observational, analytical, retrospective cohort study was conducted. Data were obtained from medical records of two oncology hospitals in São Paulo, Brazil. Patients diagnosed with colorectal adenocarcinoma were eligible; ECOG 0 to 2; stage IIA with less than 12 resected lymph nodes, IIB and IIC, submitted to curative surgery; distal tumor more than 12 cm from the anal verge by endoscopy and/or above the peritoneal reflection at surgery; absence of gross or microscopic evidence of residual disease after surgery. The primary endpoint was progression-free survival (PFS), and the secondary endpoint was overall survival (OS).

Results: From 2014 to 2020, 32 eligible patient records were identified. Of these, the median age was 65 years, 53.1% men and 68.8% with ECOG 0. The left colon was the predominant location (28.1%), rectosigmoidectomy the most common surgery (43.8%) and 28.1% had less than 12 resected lymph nodes. Recurrence occurred in 28.1%, mainly in the lungs (12.5%). Most received adjuvant chemotherapy with oxaliplatin (62.5%). Survival analysis showed a median PFS of 70.9 months and OS greater than 105 months from the start of treatment. There was no significant difference in PFS between patients according to the number of resected lymph nodes, or in OS between those using oxaliplatin or not.

Conclusion: Adjuvant oxaliplatin increases disease-free survival and overall survival in patients with colorectal adenocarcinoma EC IIA with less than 12 resected lymph nodes, IIB and IIC, although there is a need for controlled and prospective studies as it was noted that the literature is still is not unanimous as to the results.

Corresponding author: Vanessa Armenio Scontre (e-mail: [e-mail]).

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
06 May 2025