Analysis of results of radiotherapy for oropharyngeal cancer.

Abstract

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. 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. 95 patients underwent definitive radio- or radio-chemotherapy (RCT) for histologically squamous cell, oropharyngeal carcinoma at our Institute between 1January 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). 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 tohave 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 alsoobserved in HPV-associated cases. For HPV- lesions, RCT had a stronger effect on LC than RT alone(64 vs43%, P = 0.03). HPV-associated malignancies show better survival outcomes toradio ± 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.