A large centre study of pathological and clinical characteristics of signet ring and mucinous colorectal adenocarcinomas.

e15672 Background: Colorectal carcinoma is a rapidly growing public health problem worldwide. In India, a historically low prevalence country, rates have been steadily rising. Signet ring cell and mucinous morphologies of adenocarcinoma are more commonly reported in India than in the west and are generally associated with poorer prognosis. The aim of this study is to evaluate the clinical and pathological characteristics associated with these tumor types and draw comparisons between the uncommon signet and mucinous tumors, and the relatively common adenocarcinomas. Methods: This was a retrospective study utilising data of 941 patients with biopsy confirmed adenocarcinomas from 2019 to 2023 from a comprehensive database of a tertiary cancer care centre in South India. The 941 patients were divided into three groups based on tumor histology; Signet ring cell carcinoma, mucinous adenocarcinoma and non signet ring cell or mucinous adenocarcinomas. Demographic characteristics like gender and age, along with clinicopathological data such as location of tumor, stage during presentation (TNM stage) and presence of metastasis were extracted. These features were compared between adenocarcinomas and their mucinous and signet ring cell subtypes. Results: Mucinous and signet ring adenocarcinoma consisted of 10.9% and 8.7% of all diagnosed colorectal cancers during the study period. Signet ring and mucinous adenocarcinomas were both significantly associated with a younger age at presentation than normal adenocarcinomas (p < 0.05). Signet ring tumors were more likely to present at an advanced T stage (p < 0.05) and N stage (p < 0.05) as opposed to other histological types. Neither signet ring cell nor mucinous tumors were significantly associated with the presence of metastatic disease at presentation.(p > 0.05). Mucinous tumors were more likely to be found in the colon than in the rectum when compared to other histological subtypes (p < 0.05). There was no gender predilection for any of the three histological subtypes of colorectal cancer studied. Conclusions: Signet ring cell and mucinous adenocarcinomas have unique clinical and pathological characteristics. Our study shows that both signet ring cell and mucinous cancers behave differently from normal adenocarcinomas. Both types appear to have a predilection to younger patients, with signet ring cell tumors presenting at a later stage.