Patterns of Care and Comparison of Outcomes Between Primary Anal Squamous Cell Carcinoma and Anal Adenocarcinoma

BACKGROUND The management of adenocarcinoma of the anus can be challenging because there are few data on outcomes and trends in its treatment to date. OBJECTIVE This study aimed to compare and analyze the patterns of care and survival outcomes of patients with anal squamous cell carcinoma and anal adenocarcinoma. DESIGN This was a retrospective study. SETTING This study was performed by utilizing the National Cancer Database. PATIENTS We selected a total of 19,539 patients between 2004 and 2014 with stage II to III squamous cell carcinoma or adenocarcinoma of the anus. INTERVENTION The treatment groups analyzed were surgery alone, neoadjuvant chemoradiation followed by surgery, surgery followed by adjuvant chemoradiation, or definitive chemoradiation. MAIN OUTCOME MEASURES Patient- and clinical-related factors were compared between the 2 groups. Kaplan-Meier and Cox proportional hazards regression models were used to assess overall survival. RESULTS Of the patients studied, 18,346 (93.9%) had primary squamous cell carcinoma and 1193 (6.1%) had primary adenocarcinoma of the anus. The 5-year overall survival for stage II squamous cell carcinoma was 69.2%, and, for stage II adenocarcinoma, 5-year overall survival was 54.2% (p < 0.001). The 5-year overall survival for stage III squamous cell carcinoma was 55.2%, and, for stage III adenocarcinoma, 5-year overall survival was 32.9% (p < 0.001). On multivariable Cox regression, treatment with chemoradiation alone (HR, 0.67; p = 0.008) was associated with improved survival in squamous cell carcinoma. For the adenocarcinoma group, stage III disease (HR, 2.26; p < 0.001) and high tumor grade (HR, 1.59; p < 0.011) had a negative impact on survival, but there were no differences in survival based on the type of treatment received. LIMITATIONS The National Cancer Database does not include information on specific chemotherapeutic or immunotherapy agents given to patients, nor does it provide the exact cause of death. CONCLUSIONS Anal adenocarcinoma in comparison to anal squamous cell carcinoma had a lower 5-year overall survival stage for stage. Anal adenocarcinoma appears to be treated similarly to the rectal cancer paradigm, with frequent use of neoadjuvant chemoradiation. See Video Abstract at http://links.lww.com/DCR/B50. PATRONES DE EL CUIDADO Y COMPARACION DE RESULTADOS ENTRE EL CARCINOMA DE CELULAS ESCAMOSAS ANAL PRIMARIO Y EL ADENOCARCINOMA ANAL: El tratamiento del adenocarcinoma del ano puede ser un desafio ya que hasta la fecha, hay pocos datos sobre los resultados y las tendencias en su tratamiento.Comparar y analizar los patrones de el cuidado y resultados de supervivencia de pacientes con carcinoma anal de celulas escamosas y adenocarcinoma anal.Este fue un estudio retrospectivo.Este estudio se realizo utilizando la Base de Datos Nacional de Cancer (National Cancer Database, NCB).Seleccionamos un total de 19,539 pacientes entre el 2004-2014 con carcinoma de celulas escamosas en estadio II-III o adenocarcinoma del ano.Los grupos de tratamiento analizados fueron solo cirugia, quimiorradiacion neoadyuvante seguida por cirugia, cirugia seguida por quimiorradiacion adyuvante o quimiorradiacion definitiva.Se compararon los factores clinicos y de pacientes entre los dos grupos. Se utilizaron modelos de regresion de riesgos proporcionales de Kaplan-Meier y Cox para evaluar la supervivencia general.18,346 (93.9%) tenian carcinoma primario de celulas escamosas y 1,193 (6.1%) tenian adenocarcinoma primario del ano. La supervivencia global a 5 anos para el carcinoma de celulas escamosas en estadio II fue del 69.2% y para el adenocarcinoma en estadio II fue del 54.2% (p < 0.001). La supervivencia global a cinco anos para el carcinoma de celulas escamosas en estadio III fue del 55.2% y para el adenocarcinoma en estadio III fue del 32.9% (p < 0.001). En la regresion de Cox multivariable, el tratamiento con quimiorradiacion sola (proporcion de riesgo 0.67, p = 0.008) se asocio con una mejor supervivencia en el carcinoma de celulas escamosas. Para el grupo de adenocarcinoma, la enfermedad en estadio III (proporcion de riesgo 2.26, p < 0.001) y el alto grado tumoral (proporcion de riesgo 1.59, p < 0.011) tuvieron un impacto negativo en la supervivencia, pero no hubo diferencias en la supervivencia segun el tipo de tratamiento recibido.La Base de Datos Nacional de Cancer no incluye informacion sobre agentes quimioterapeuticos o de inmunoterapia especificos que se administran a los pacientes, ni proporciona la causa exacta de la muerte.El adenocarcinoma anal en comparacion con el carcinoma anal de celulas escamosas tuvo una supervivencia general inferior a 5 anos, etapa por etapa. El adenocarcinoma anal parece tratarse de manera similar al paradigma del cancer rectal, con el uso frecuente de quimiorradiacion neoadyuvante. Vea el video del resumen en http://links.lww.com/DCR/B50.