Evaluation of the pathologic response to neoadjuvant treatment in rectal cancer. Experience at the Instituto de Cancerología de Medellín (Colombia, 2011-2017). / Evaluación de la respuesta patológica al tratamiento neoadyuvante en cáncer de recto. Experiencia del Instituto de Cancerología de Medellín (Colombia, 2011-2017).

ABSTRACT

INTRODUCTION AND AIMS: Neoadjuvant therapy in rectal cancer is associated with a decrease in tumor size and is the therapeutic indication for patients with T3 or T4 tumors or lymph node involvement. Our aim was to describe the frequency of pathologic response and the survival rate in patients that underwent neoadjuvant therapy for rectal cancer. MATERIALS AND METHODS: A retrospective follow-up study with a survival analysis was conducted. Patients with locally advanced rectal cancer that received neoadjuvant treatment and were operated on at the Instituto de Cancerología Las Américas (Medellín, Colombia) were analyzed. Survival was calculated using the Kaplan-Meier method. RESULTS: A total of 152 patients were included. Mean patient age was 59 years (12.8 SD), 53.9% were men, and 58.6% of the patients were diagnosed with stage IIIB disease. The pathologic complete response (pCR) was achieved in 17% of the patients. A total of 146 (96.1%) patients received the chemoradiotherapy protocol. Fifty-two (34.2%) patients developed metastasis and/or relapse, and one (3.8%) of those patients had presented with pCR. The median follow-up period was 33 months (Q1-Q3 20-45), with an overall survival rate of 79.5% (95% CI 70.9-85.8). The 5-year survival rate for the patients that had pCR was 80% (95% CI 20.3-96.9). CONCLUSIONS: The frequency of pCR was similar to that in other published studies and disease recurrence was lower, compared with patients with no response. The 5-year survival rate in patients with pCR was high, albeit lower than that reported in other studies.