Analysis of results of radiotherapy for oropharyngeal cancer.

Abstract

Introduction: Smoking and alcohol consumption remain the two most important risk factors for the development of oropharyngeal tumours, but there is an increasing number of younger patients (age <50 years) with human papillomavirus (HPV) association origin, also known as positivity. The role of radiotherapy (RT) in the treatment of this disease is paramount.

Aim: To describe the radiotherapy results for oropharyngeal tumours and to search for prognostic parameters that influence the response of these malignant lesions to radio-chemotherapy.

Methods: 95 patients underwent definitive radio- or radio-chemotherapy (RCT) for histologically squamous cell, oropharyngeal carcinoma at our Institute between 1 January 2019 and 31 December 2020, of which 51 (54%) received the latter. The mean age was 61.9 years (37-82 years) and the male-female ratio was 69:26. The average total dose was 69 Gy (range: 54-70 Gy).

Results: The 5-year local control (LC), cancer-specific survival (CCS), and overall survival (OS) calculated by the Kaplan-Meier method were 71, 69, and 58%, respectively. Forty-four cases (46%) were confirmed to have HPV involvement. HPV positive (+) tumours showed significantly better behaviour compared to HPV negative (-) cases in LC, CCS and OS. Smoking had a significant negative effect on cure rates: LC, CCS and OS were better in non-smokers. A significant negative effect of smoking on survival was also observed in HPV-associated cases. For HPV- lesions, RCT had a stronger effect on LC than RT alone (64 vs 43%, P = 0.03).

Conclusions: HPV-associated malignancies show better survival outcomes to radio ± chemotherapy than their HPV- counterparts. In all cases, smoking worsens the response to treatment. For HPV- tumours, chemotherapy with radiation, compared to irradiation alone, has a more significant effect on survival outcomes, whereas for HPV+ tumours this effect is less pronounced.