Signet Ring Cell Colorectal Cancers portend an aggressive biology: A 17-year analysis of operable colorectal cancers at a tertiary hospital in Pakistan

Abstract

Introduction: Primary signet ring cell carcinoma (SRCC) is a rare variant of colorectal cancer, reportedly comprising 0.1%-2.6% of all colorectal cancers. Due to manifestations occurring later in the course of the disease, the overall survival is reportedly poorer than that of colorectal adenocarcinoma. The Southeast Asian region has been observed to have a higher likelihood of having the signet ring cell carcinoma variant. Objective: The following study determines the overall proportion and histopathological characteristics of colorectal cancer in a Pakistani population across a tertiary care hospital.Methods: The histopathology reports of the colon and/or rectum specimens diagnosed as primary colorectal carcinoma were identified and reviewed at the Aga Khan University Hospital (AKUH). These included all the surgical specimens submitted to AKUH from January 2002 to December 2018. Biopsies and histopathological specimens with fragmented bowel, lack of orientation of tissue, and post chemotherapeutic complete resolution of the tumor were excluded.Results: Of the 2,662 surgical specimens of colorectal carcinoma identified, 1,708 specimens met the inclusion criteria. The cohort consisted of 62.4% (n = 1065) males, with an overall mean age of 50.41 years (SD = 16.98). Among these patients, 29.5% (n = 504) were 40 years of age or younger, 19% (n = 325) were between the ages of 41 and 50, and 51.5% (n = 879) were older than 50 years (p<0.001). The frequency of signet ring cell cancer was found to be 5.4% (n = 92). The histopathological characteristics associated with worse prognosis were significantly associated with the type of tumor. Lymphovascular and perineural invasion, stage, and grade were all significantly higher in SRCC than the other types. Conclusion: Pakistani population tends to present with colorectal cancer at a younger age and with poorer prognostic features including higher rates of signet ring cell cancer.