P3022 - Primary Squamous Cell Carcinoma of the Colon Is Extremely Rare and Shows Poor Survival

Leon Protiva, BS¹, Gyanprakash Ketwaroo, MD², Petr Protiva, MD, MPH^3
1Fairfield College Preparatory School, Fairfield, CT; ²Yale University School of Medicine, New Haven, CT; ³Yale University School of Medicine and VA Connecticut Healthcare System, New Haven, CT

Introduction: Primary squamous cell carcinoma (SCC) of the colon is a rare malignancy with uncertain prognosis and management. Previous research demonstrated that squamous histology in pancreatic cancer is linked to a worse prognosis, regardless of other clinical and biological characteristics (Nagar et al., Gastroenterology, DDW 2022). In this study, we aimed to analyze cancer-specific survival using the Surveillance, Epidemiology, and End Result database (SEER). We compared SCC to colon adenocarcinoma while independently considering additional factors associated with survival.

Methods: We used SEER*Stat software to extract U.S. survival data from the SEER Database for colon cancer. The data spanned from 1975 to 2016 and included individuals over 20 years old with a single malignancy. We collected demographic information (age, sex, race, marital status) and clinical details (date of diagnosis, tumor histology, stage and grade, treatment status, survival time, cause of death). Rectal cancers were excluded to avoid confounding with anal malignancies.








To compare survival rates, we used the Mantel-Haenszel Log-Rank Test. We estimated relative hazard ratios (HRs) for cancer-related death within a 5-year period following diagnosis using the Cox proportional hazard model. We also examined the independent effect of cancer histological type by adjusting for covariates in the Cox model. The data was analyzed using SAS 9.4 software and R. The significance level for the P-value was set at < 0.05 for a two-sided test.

Results: We identified 397,228 cases of colon cancer in the SEER database, including 202 cases of SCC and 397,026 cases of adenocarcinoma, all with complete survival data. In Figure 1, SCC of the pancreas demonstrates significantly worse survival compared to pancreatic adenocarcinoma (P< 0.001). Table 1 presents the results of multivariate Cox regression analysis, evaluating the independent effects of the two pancreatic cancer types. The model considered relevant covariates, listed in the table with their respective HR and P-values.

Discussion: The analysis of the large dataset on primary colon squamous cancer indicated a strong association with significantly poorer survival compared to adenocarcinoma. These findings highlight the considerable challenges in managing this rare form of cancer, particularly in determining the most effective chemotherapy. It is crucial to gather additional clinical and molecular data to establish optimal treatment strategies of SCC.



Disclosures:


Leon Protiva, BS¹, Gyanprakash Ketwaroo, MD², Petr Protiva, MD, MPH³. P3022 - Primary Squamous Cell Carcinoma of the Colon Is Extremely Rare and Shows Poor Survival, ACG 2023 Annual Scientific Meeting Abstracts. Vancouver, BC, Canada: American College of Gastroenterology.