Real-World Outcomes of Colorectal Signet Ring Cell Carcinoma: Clinicopathological Characteristics, Treatment Patterns, and Survival

Abstract

Background: Colorectal signet-ring cell carcinoma (SRCC) is a rare and aggressive histological subtype of colorectal cancer (CRC) characterised by advanced stage at presentation and poor prognosis. Data from the Indian subcontinent remain limited. This study aimed to evaluate the clinicopathological characteristics, treatment patterns, prognostic factors, and survival outcomes of patients with colorectal SRCC treated at a tertiary cancer centre. Methods: A retrospective observational study was conducted, including patients with histologically confirmed colorectal SRCC treated at a tertiary cancer centre. Demographic, clinical, pathological, treatment, and survival data were collected. Overall survival (OS) was estimated using the Kaplan-Meier method. Prognostic factors associated with OS were evaluated using univariate and multivariable Cox proportional hazards regression analyses. Results: A total of 263 patients were included. The median age was 37 years (IQR, 28.5-49), with 58.2% of patients younger than 40 years, and males constituted 63.1% of the cohort. The rectum was the predominant primary site (73.4%), and 93.2% of patients presented with stage III or IV disease. Curative-intent treatment was performed in 73.8% of patients, with total neoadjuvant therapy followed by surgery being the most common treatment strategy (27.2%). Among patients receiving neoadjuvant treatment, a complete response was achieved in 11.0%, whereas disease progression occurred in 22.9%. Recurrence developed in 48.6% of surgically treated patients, with the peritoneum representing the most common site of recurrence (36.4%). After a median follow-up of 35 months, the median DFS was 21 months (95% CI: 15.8-26.1), with a two-year DFS rate of 40.3±4.5%, while the median OS was 30 months (95% CI: 26.1-33.9) with a two-year OS rate of 62.1±4.4%. On univariate analysis, positive lymph node status, lymphovascular invasion, perineural invasion, positive resection margins, and elevated baseline carcinoembryonic antigen (CEA) were significantly associated with worse OS, whereas neoadjuvant therapy was associated with improved survival. In multivariable analysis, pathological nodal stage, positive resection margins, and elevated baseline CEA showed trends towards poorer survival but did not reach statistical significance. Conclusion: Colorectal SRCC predominantly affects young patients and presents at an advanced stage with aggressive clinicopathological features and poor oncological outcomes. Advanced nodal disease, adverse pathological features, and elevated baseline CEA were associated with inferior survival. Early diagnosis, multidisciplinary management, and prospective multicentre studies incorporating comprehensive molecular profiling are required to improve outcomes in this challenging disease.