Radical Radiotherapy in Head and Neck Squamous Cell Carcinoma: An Analysis of Prognostic and Therapeutic Factors

Abstract

Aims Head and neck squamous cell carcinoma (HNSCC) continues to be a leading cancer in developing countries. Definitive radiation therapy either primary or as postoperative adjuvant is offered to most patients. We aimed to identify prognostic and therapeutic factors that affect locoregional control and survival in patients undergoing radical radiotherapy for head and neck squamous cell cancers. Materials and methods A retrospective analysis of 568 previously untreated patients with squamous head and neck cancers, who received radical radiotherapy between 1990 and 1996, using local control, locoregional control and disease-free survival (DFS) as outcome measures. Results With a median follow-up of 18 months for living patients, the 5-year local control, locoregional control and DFS for all 568 patients were 53%, 45% and 41%, respectively, for all stages combined. The 5-year local control, locoregional control and DFS as per the American Joint Committee on Cancer stage grouping were 78%, 70% and 70%; 64%, 59% and 57%; 51%, 42% and 37%; and 40%, 27% and 22% from stages I to IV, respectively, with highly significant P values. Patients receiving higher doses (≥66 Gy) had a significantly better outcome compared with lower doses. The 5-year local control (59% vs 48%, P = 0.0015), locoregional control (47% vs 41%; P = 0.0043) and DFS (44% vs 37%; P = 0.0099) were significantly better in patients receiving ≥66 Gy. Site of primary also affected outcome significantly, with oral cavity lesions faring badly. Conclusion Tumour stage remains the most important factor affecting outcome in radical radiotherapy of HNSCC. A definite dose–response relationship exists with higher total doses, leading to better local control, locoregional control and DFS in all stages. Site of primary affects outcome too, with laryngeal primaries doing well and oral cavity cancers faring the worst.