Abstract
Simple SummaryTransverse colon cancer (TCC) is mostly included among right-sided colon cancer, and sometimes even excluded at all, thus it is not completely clear if they present total similarities with right-sided ones or if they have their own specific features. With a median follow-up of 34 months, we concluded that TCC shares some clinicopathological characteristics with left-sided colon cancer and many others with the right-sided ones, but only poorly/undifferentiated tumor grade and BRAF V600E mutation are independent prognostic factors for survival, regardless of tumor stage. The present study provides more insightful knowledge of clinicopathological characteristics of TCC patients, emphasize the role of BRAF mutation since the early stage of disease and lay the basis for new treatment algorithms in this specific setting of colon cancer.Background: Although most of the analyses included transverse colon cancers (TCC) among right colon cancer (RCC), it is not completely clear if they present total similarities with RCC or if they have their specific features. Therefore, we present an observational study to evaluate clinicopathological characteristics and survival data of patients with TCC. Methods: We retrospectively reviewed 450 RCC, of whom 97 stages I–IV TCC were included in this multicenter study; clinicopathological and molecular parameters were analyzed to identify prognostic factors for disease-free survival (DFS) and overall survival (OS). Results: Most of TCC cases were male (61%), with ≤70 years old (62%), and good performance status (ECOG PS 0, 68%). According to WHO classification, 41 (49%) and 40 (48%) tumors were classified as well to moderate and poorly/undifferentiated respectively, regardless of mucinous component (30%). About molecular data, 8 (26%), 45 (63%), and 14 (24%) were MSI-H, KRAS wild-type, and BRAF V600E mutant, respectively. With a median follow-up of 34 months, there were 29 and 50 disease recurrences and deaths respectively. Charlson comorbidity index ≥5 was a significant prognostic factor for DFS (HR = 7.67, 95% CI 2.27–25.92). Colon obstruction/perforation (HR = 2.65, 95% CI 1.01–7.01), and BRAF mutant (HR = 3.03, 95% CI 0.97–9.50) cases showed a worst, despite not statistically significant, DFS. Whereas for OS, at the multivariate model, only tumor grade differentiation (HR = 5.26, 95% CI 1.98–14.01) and BRAF mutation status (3.71, 95% CI 1.07–12.89) were independent prognostic factors. Conclusions: Poorly/undifferentiated tumor grade and BRAF V600E mutation are independent prognostic factors for OS in TCC. Further prospective clinical trials are needed to better define TCC treatment in order to improve patient outcome.
Highlights
The right-sided and left-sided primary colon tumors are defined as those originating proximally or distally to the splenic colic flexure, based on the different embryological origin from the midgut and hindgut, respectively
We retrospectively reviewed 450 right colon cancer (RCC), of whom 97 stages I–IV transverse colon cancers (TCC) were included in this multicenter study; clinicopathological and molecular parameters were analyzed to identify prognostic factors for disease-free survival (DFS) and overall survival (OS)
A number of studies have shown that patients affected with right colon cancer (RCC) are predominantly female and older than those affected by left colon cancer (LCC) [2]
Summary
The right-sided and left-sided primary colon tumors are defined as those originating proximally or distally to the splenic colic flexure, based on the different embryological origin from the midgut and hindgut, respectively. Proximal tumors tend to involve bulky, exophytic, polypoid lesions growing into the colon lumen and are associated with advanced stages, increased tumor size, poorly differentiated grade, and different molecular biological tumor patterns [3]. As a matter of fact, colorectal cancers (CRCs) may have different histological and genetic characteristics as well as a different outcome in terms of disease progression and overall survival based on the specific tumor location [6,7,8]. Methods: We retrospectively reviewed 450 RCC, of whom 97 stages I–IV TCC were included in this multicenter study; clinicopathological and molecular parameters were analyzed to identify prognostic factors for disease-free survival (DFS) and overall survival (OS).
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