Laxmi B Chavali, Adana A M Llanos, Jing-Ping Yun, Stephanie M Hill, Xiang-Lin Tan, Lanjing Zhang1. 1. From the Department of Epidemiology, Rutgers School of Public Health, Piscataway, New Jersey (Ms Chavali and Drs Llanos and Tan); the New Jersey State Cancer Registry (Ms Hill), Rutgers Cancer Institute of New Jersey (Drs Llanos, Tan, and Zhang), New Brunswick; the Department of Pathology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Guangzhou, China (Dr Yun); the Department of Medicine, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey (Dr Tan); the Department of Pathology, University Medical Center of Princeton, Plainsboro, New Jersey (Dr Zhang); the Department of Biological Sciences, Rutgers University, Newark, New Jersey (Dr Zhang); and the Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, New Jersey (Dr Zhang).
Abstract
CONTEXT: - According to the American Joint Committee on Cancer's Cancer Staging Manual, 7th edition, TNM classification, tumor deposit (TD)-positive colorectal cancers (CRCs) are classified as N1c. The effects of radiotherapy and the effects of the updated American Joint Committee on Cancer 7th edition TNM N1c classification for patients with TD-positive CRC are unclear. OBJECTIVE: - To investigate outcomes of radiotherapy in patients with resected TD-positive CRC. DESIGN: - Resected TD-positive CRCs diagnosed from 2010 to 2014 were identified in the Surveillance, Epidemiology, and End Results 18 database. Factors associated with overall survival (OS) and cancer-specific survival (CSS) were investigated using Kaplan-Meier and Cox proportional hazards models. RESULTS: - We included 2712 qualified CRC patients, who either underwent adjuvant radiotherapy (n = 187; 6.9%) or received no radiotherapy (n = 2525; 93.1%). Univariate Cox proportional models showed improved CSS among all CRC patients who underwent adjuvant radiotherapy (CSS hazard ratio, 0.73; 95% CI, 0.57-0.95) and among rectal cancer patients when separated by location (hazard ratio, 0.57; 95% CI, 0.40-0.83), although these associations were attenuated in multivariable-adjusted models. There was improved OS among rectal cancer patients (hazard ratio, 0.77; 95% CI, 0.59-0.99). In subgroup analyses, radiotherapy was not associated with OS or CSS in either metastatic or nonmetastatic CRC patients. Instead, N1c category (versus N0) was associated with a worse OS (hazard ratio, 1.43; 95% CI, 1.31-1.57) but was not associated with CSS. CONCLUSIONS: - Radiotherapy did not independently improve OS among TD-positive CRC patients. In this study, classifying TD positivity as N1c was associated with worse OS than classifying TD positivity as N0. The findings seem to challenge the benefits of radiotherapy and the new N1c classification of TD for TD-positive CRC patients.
CONTEXT: - According to the American Joint Committee on Cancer's Cancer Staging Manual, 7th edition, TNM classification, tumor deposit (TD)-positive colorectal cancers (CRCs) are classified as N1c. The effects of radiotherapy and the effects of the updated American Joint Committee on Cancer 7th edition TNM N1c classification for patients with TD-positive CRC are unclear. OBJECTIVE: - To investigate outcomes of radiotherapy in patients with resected TD-positive CRC. DESIGN: - Resected TD-positive CRCs diagnosed from 2010 to 2014 were identified in the Surveillance, Epidemiology, and End Results 18 database. Factors associated with overall survival (OS) and cancer-specific survival (CSS) were investigated using Kaplan-Meier and Cox proportional hazards models. RESULTS: - We included 2712 qualified CRC patients, who either underwent adjuvant radiotherapy (n = 187; 6.9%) or received no radiotherapy (n = 2525; 93.1%). Univariate Cox proportional models showed improved CSS among all CRC patients who underwent adjuvant radiotherapy (CSS hazard ratio, 0.73; 95% CI, 0.57-0.95) and among rectal cancerpatients when separated by location (hazard ratio, 0.57; 95% CI, 0.40-0.83), although these associations were attenuated in multivariable-adjusted models. There was improved OS among rectal cancerpatients (hazard ratio, 0.77; 95% CI, 0.59-0.99). In subgroup analyses, radiotherapy was not associated with OS or CSS in either metastatic or nonmetastatic CRC patients. Instead, N1c category (versus N0) was associated with a worse OS (hazard ratio, 1.43; 95% CI, 1.31-1.57) but was not associated with CSS. CONCLUSIONS: - Radiotherapy did not independently improve OS among TD-positive CRC patients. In this study, classifying TD positivity as N1c was associated with worse OS than classifying TD positivity as N0. The findings seem to challenge the benefits of radiotherapy and the new N1c classification of TD for TD-positive CRC patients.