Definitive Hypofractionated Simultaneous Integrated Boost Intensity-modulated Radiotherapy (60 Gy in 25 Fractions) in Elderly Patients with Locally Advanced Head and Neck Cancer Ineligible for Concurrent Chemotherapy: A Prospective, Single-arm Feasibility Study

Abstract

A BSTRACT Elderly patients with head and neck squamous cell carcinoma (HNSCC) often cannot tolerate prolonged conventional radiotherapy and are under-represented in trials. As the meta-analysis of chemotherapy in head and neck cancer meta-analysis shows the benefit of concurrent chemotherapy diminishes with age, radiotherapy alone is the appropriate backbone. We evaluated the feasibility of hypofractionated simultaneous integrated boost (SIB) intensity-modulated radiotherapy (IMRT) delivering 60 Gy in 25 fractions over 5 weeks in chemotherapy-ineligible elderly HNSCC patients. Patients aged ≥70 years with locally advanced HNSCC, Eastern Cooperative Oncology Group 0–2, unfit for or declining concurrent chemotherapy received SIB-IMRT (60, 56, and 50 Gy in 25 fractions to high-, intermediate- and low-risk planning target volumes). The primary endpoint was feasibility (≥90% of planned dose within 35 days; Grade 4 acute toxicity <25%). Acute toxicity was graded by the RTOG criteria and response by RECIST v1.1. Late toxicity is not reported here. Ten patients were enrolled (median age – 74.8 years; 8 male), all with stage III/IVA disease. All completed the planned dose; 9 (90%) within 35 days. Grade 3 mucositis and dermatitis each occurred in two patients (20%); no Grade 4 toxicity occurred. Six (60%) required temporary enteral nutrition, none permanent. At 4–6 weeks, 6 patients (60%) achieved a complete and 4 (40%) a partial response. Hypofractionated SIB-IMRT (60 Gy in 25 fractions) is feasible and acceptably tolerated in the short term in this population. These findings are hypothesis-generating: follow-up is insufficient to establish durable locoregional control or late toxicity, and a larger study with geriatric assessment and long-term follow-up is required.