BACKGROUND: Extended colectomy is considered a standard treatment for neoplasia associated with ulcerative colitis, but there is limited supporting evidence, particularly from large-scale studies. OBJECTIVE: This study aimed to assess the prognostic benefits of extended colectomy in patients with neoplasia associated with ulcerative colitis using a nationwide database. DESIGN: Multicenter retrospective study. SETTINGS: Forty-three institutions in Japan participated in this study. PATIENTS: The medical records of patients with ulcerative colitis and diagnosed intestinal neoplasia between 1983 and 2020 at 43 institutions were analyzed. MAIN OUTCOME MEASURES: Five-year overall survival and disease-free survival were assessed on the basis of different surgical procedures, with a subgroup analysis comparing neoplasia associated with ulcerative colitis to sporadic cancer. RESULTS: Among 879 patients, 801 were diagnosed with neoplasia associated with ulcerative colitis and 78 with sporadic cancer. The 5-year disease-free survival for total proctocolectomy and subtotal colectomy were similar (87.8% and 83.9%), and both were superior to segmental colectomy (72.0%). When comparing neoplasia associated with ulcerative colitis to sporadic cancer, extended colectomy (total proctocolectomy and subtotal colectomy) showed significantly better outcomes for neoplasia associated with ulcerative colitis, whereas no significant difference was observed for sporadic cancer. Multivariable analysis revealed a significantly better prognosis for extended colectomy compared to segmental colectomy in neoplasia associated with patients with ulcerative colitis, both in overall survival and disease-free survival ( p < 0.001). LIMITATION: Nonrandomized retrospective study design. CONCLUSIONS: This nationwide cohort study supports extended colectomy as the criterion standard for neoplasia associated with ulcerative colitis management and underscores the importance of accurate diagnosis to distinguish between neoplasia associated with ulcerative colitis and sporadic cancer for optimal treatment decisions. See Video Abstract. DIFERENCIA EN EL BENEFICIO PRONSTICO ENTRE LA COLECTOMA EXTENDIDA Y SEGMENTARIA PARA PACIENTES CON NEOPLASIA ASOCIADA A COLITIS ULCERATIVA UN ESTUDIO MULTICNTRICO A NIVEL NACIONAL: ANTECEDENTES:La colectomia extendida se considera el tratamiento estandar para la neoplasia asociada con la colitis ulcerativa, pero hay evidencia de respaldo limitada, particularmente de estudios a gran escala.OBJETIVO:Este estudio tuvo como objetivo evaluar los beneficios pronosticos de la colectomia extendida en pacientes con neoplasia asociada con colitis ulcerativa utilizando una base de datos nacional.DISENO:Estudio retrospectivo multicentrico.ESCENARIO:Cuarenta y tres instituciones en Japon participaron en este estudio.PACIENTES:Se analizaron pacientes con colitis ulcerativa diagnosticados con neoplasia intestinal entre 1983 y 2020 en 43 instituciones.PRINCIPALES MEDIDAS DE RESULTADOS:Se evaluaron la supervivencia general a cinco anos y la supervivencia libre de enfermedad en funcion de diferentes procedimientos quirurgicos, con un analisis de subgrupos que comparaba la neoplasia asociada con colitis ulcerativa con el cancer esporadico.RESULTADOS:Entre 879 pacientes, 801 fueron diagnosticados con neoplasia asociada con colitis ulcerativa y 78 con cancer esporadico. La supervivencia libre de enfermedad a 5 anos para la proctocolectomia total y la colectomia subtotal fue similar (87,8% y 83,9%), ambas superiores a la colectomia segmentaria (72,0%). Al comparar la neoplasia asociada a la colitis ulcerativa con el cancer esporadico, la colectomia extendida (proctocolectomia total y colectomia subtotal) mostro resultados significativamente mejores para la neoplasia asociada a la colitis ulcerativa, mientras que no se observo una diferencia significativa para el cancer esporadico. El analisis multivariable revelo un pronostico significativamente mejor para la colectomia extendida en comparacion con la colectomia segmentaria en pacientes con neoplasia asociada a la colitis ulcerativa, tanto en la supervivencia general como en la supervivencia libre de enfermedad (p < 0,001).LIMITACION:Diseno de estudio retrospectivo no aleatorizado.CONCLUSION:Este estudio de cohorte a nivel nacional respalda la colectomia extendida como el estandar de oro para el manejo de la neoplasia asociada a la colitis ulcerativa y subraya la importancia de un diagnostico preciso para distinguir entre la neoplasia asociada a la colitis ulcerativa y el cancer esporadico para tomar decisiones optimas de tratamiento. (Traduccion- Dr. Francisco M. Abarca-Rendon ).