Predictive factors of complete pathological response in operated patients with locally advanced rectal cancer after chemoradiotherapy neoadjuvant treatment in Peru
Authors: R. Motta, P. Ybazeta, O. Cordova, S. Quiroz, A. Figueroa, C. Aliaga, R. Salas, J. Geronimo
Journal: Annals of Oncology (2018)

Introduction: Surgery after neoadjuvant treatment with chemoradiotherapy is the standard treatment in locally advanced rectal cancer (LARC). One of the objectives of neoadjuvant treatment is to increase the rate of R0 surgeries after tumor downstaging. The 10-30% of patients achieve complete pathological response (CPR) after chemoradiotherapy treatment, which has shown reduced local recurrence and better overall survival in several studies. However, surgery has several genitourinary, sexual and gastrointestinal postoperative complications. Because of this, the recognition of patients who would achieve CPR could allow us to consider a "watch and wait" therapeutic option instead of surgery in selected patients. The objective of this study is to determine predictive factors of CPR in order to try to identify patients in whom surgical treatment may be avoided and preserve organ function. Methods: Medical records of operated patients with LARC were reviewed. All patients who were operated and received concurrent chemoradiotherapy with capecitabine (dosis 825 mg/m2 bi) and radiotherapy (total dose = 5040 cGy/28 fx) as neoadjuvant treatment during period 2011-2015 at Edgardo Rebagliati Martins Hospital were included. All patients who had incomplete information in their medical records were excluded. The studied factors were: the platelet-lymphocyte ratio (PLR), the neutrophil-lymphocyte ratio (NLR), body mass index (BMI) and CEA. All were determined before neoadjuvant treatment. Comparisons of the CPR rate according to clinical characteristics were performed using the Chi square test. In multivariate analysis, the factors associated with CPR were determined by the logistic regression model. The data were analyzed using the SPSS program, version 24. Results: A total of 57 patients were finally included. The median age was 63.6 years and the 57.8% were female. All had an ECOG 0-1 and an adenocarcinoma subtype, 81.2% were G2. 50.9% had a CE II and 49.1% had a CE III. The neoplasia was located in lower rectum in 49.2% of patients; meanwhile the 40.36% were located in middle rectum and 10.52% in middle-lower rectum. 10 patients achieved complete clinical response after neoadjuvant treatment. The 49.1% of patients underwent abdominoperineal resection (APR), 19.3% ultra-low anterior resection, 19.3% local resection and 12.3% low anterior resection. 17.5% of patients achieved CPR. In the univariate analysis, the CPR rate shows a significant difference in relation to the PLR (p = 0.025) and a statistical tendency in terms of CEA (p = 0.062). The rest of the clinical characteristics were not significant. In the multivariate analysis, using the logistic regression model, the only variable associated with CPR was CEA (p = 0.027, OR = 11.8). The PLR was not significant (p = 0.077). Conclusion: Patients with LARC with a CEA < 3 before neoadjuvant are more likely to achieve CPR. There is a trend that states that patients with LARC with a PLR < 150 before neoadjuvant are more likely to achieve CPR. Studies with a larger number of patients are needed to analyze these results. Predictive factors of CPR may help to choose between different strategies of treatment.