Survival Rate of Patients With Orbital Squamous Cell Carcinoma in Kenyatta National Hospital; a Comparative Retrospective Cohort Study

Abstract

Background: Orbital Squamous cell carcinoma (SCC) is an advanced stage of a spectrum of disease referred to as ocular surface squamous neoplasia (OSSN). Orbital invasion may occur if left untreated or from residual tumour cells after treatment of OSSN. The mainstay of treatment at this stage is exenteration with or without adjuvant radiotherapy. In Kenya most cases of orbital SCC are diagnosed when it is in the late stage. However, there is little evidence that the use of adjuvant radiotherapy in the treatment and management of the disease improves survival of the patients. Objective: To compare survival rates in patients with orbital SCC who underwent exenteration alone versus those who were prescribed adjuvant radiotherapy post-exenteration at Kenyatta National Hospital (KNH). Methods: All histologically confirmed exenteration cases of orbital SCC during the period January 2013-December 2016 were included. Cases were identified from the KNH cancer database. Clinical information from medical records was captured in a questionnaire and vital status confirmed from participants or next of kin. The primary outcome measure was to compare one-year survival rates between the treatment groups using the Kaplan-Meier method and correlates of survival were determined using univariate analysis. Statistical Package for Social Scientists (SPSS) Version 22.0 and Stata version 15 were used for analysis. Results: A total of 56 participants were included, with 14 in the exenteration alone group and 42 in the exenteration plus adjuvant radiotherapy group. Patients who had exenteration alone had a trend to higher survival than exenteration plus radiotherapy both by intention-to-treat (100% vs 55%, p=0.07) and per-protocol (84% vs 77%, p=0.51) but this difference was not statistically significant. Survival probability was affected only by intracranial tumour extension (p=0.01) all other factors assessed including sex, HIV status, ART use, occupation and non-completion of radiotherapy were not statistically significant. Repeat surgery was performed in 7.1% of participants. Conclusion: There was no difference in survival rates between patients who underwent exenteration alone versus those who underwent exenteration and received adjuvant radiotherapy. Baseline characteristics did not significantly influence survival. Intracranial extension of tumour was the only factor found to negatively influence survival rates. The probability of survival was not negatively affected in those who underwent repeat surgery.