Therapeutic Outcomes of HPV Positive and HPV Negative Oropharyngeal Squamous Cell Carcinomas

Abstract

Background & Objectives : HPV associated (HPV+) oropharyngeal cancers, compared with HPV non-associated ones (HPV ? ) have different characters and significantly better outcomes. HPV and cancer characteristics differ among countries and few data is available in Indian population regarding this issue. Thus , we attempted to determine the treatment response and survival rates between HPV+ versus HPV negative oropharyngeal cancers in Indian population. Methods: This prospective observational study was conducted from December 2016 - October 2018 in patients with stage III/IV oropharyngeal squamous cell carcinomas (SCC) (n = 65). The patients received induction chemotherapy with Docetaxel, Cisplatin, 5-Fluorouracil × 3 cycles, followed by concurrent chemoradiation 66 Gy as 33 fractions along with cisplatin 40 mg/m 2 weekly. The primary outcome was treatment response rate, which was defined as per Response Evaluation Criteria in Solid Tumours (RECIST) criteria. Secondary outcomes were clinico-pathological differences between two groups, overall survival (OS), progression free survival (PFS). Results: Of the 65 patients included in the study, 17 were HPV positive and 48 patients were HPV negative. Median age in HPV positive arm is 48 years and HPV negative arm is 59 years. HPV positive patients presented with early T stage and advanced nodal (N) stage. Most common histopathology in both arms was moderately differentiated squamous cell carcinomas followed by well differentiated squamous cell carcinomas. HPV+ vs HPV ? showed the following , treatment response 82.4% vs 52.1% (p-0.029). 1 year progression free survival (PFS) of 76.5% vs 52.1% in HPV negative arm (p-0.08) & 1 year overall survival was 82.4% vs 70.8% (p- 0 .353). Grade 3 or 4 toxicities did not differ significantly between HPV positive and HPV negative arms. Conclusion: HPV positive oropharyngeal SCC patients showed significantly better treatment response than HPV negative ones. Progression free survival, overall survival and toxicity profile did not differ significantly between the two groups. Although due to small size, we did not compare data stratified by the cancer characteristics, the data is worthy to further characterize this tumour especially as HPV positive versus HPV negative.