Influence of prognostic factors on survival in lymphoma of oral cavity and maxillofacial region in a Peruvian population: A historical cohort study

Aim: To determine the influence of prognostic factors on the survival of patients who had been diagnosed with lymphoma of the oral cavity and maxillofacial region (OC/MR) and received care at the National Institute for Neoplastic Diseases (INEN). Materials and Methods: This was a retrospective cohort study. This type of study is classified as observational, analytic, longitudinal, and retrospective. The sample consisted of cases diagnosed with primary lymphoma of the OC/MR (151 altogether), over the 13 years included in the study (1997-2010). The sample only included patients for whom histopathological diagnosis was confirmed by re-evaluation of the histological section. Clinical histories were reviewed to retrieve the following variables as potential prognostic factors: age, sex, location of the lesion, size, signs/symptoms, diagnosis, clinical stage, international prognostic index, serum lactate dehydrogenase levels, extranodal involvement, and treatment. The study was approved by the hospital Institutional Review Board. The following statistical analyses were applied: (1) analysis by actuarial technique and Kaplan-Meier product-limit method for survival and (2) univariate analysis with the log-rank test and multivariate analysis using Cox regression model for prognostic factors and hazard function. Results: Out of the 151 patients diagnosed, 50 were included in the study. Survival at 2 and 5 years was 69% and 47%, respectively. Multivariate analysis showed that survival is influenced by presence of pain, clinical stage, extranodal involvement, and treatment type. A single significant variable was established as the best hazard function: clinical stage III/IV, with patients at these stages being 6.86 times more likely to die than patients at clinical stage I/II. Conclusion: Based on the methodology and statistical analyses used, it was mainly found that survival at 5 years was lower than specified in international reports and that prognostic factors influencing survival jointly were pain, clinical stage, extranodal involvement, and treatment. For hazard function, it was found that the probability of dying was high when the patient was at clinical stage III/IV, which had the greatest influence or created the highest risk of dying among all prognostic factors analyzed.