Onkológia 3/2021

Primary radiotherapy of the head and neck squamous cell carcinomas

Radiotherapy of the head and neck squamous cell carcinomas (HNSCC) constitutes notable workload at every department of radiation oncology. Head and neck cancer might be considered a model disease for research in fractionation, combination with chemotherapy and implementation of novel technologies. Primary radiotherapy remains an important treatment modality in a significant proportion of patients in various stages of HNSCC. Despite being considered a standard approach for long, conventionally fractionated radiotherapy has been largely replaced by altered fractionation either as a single modality in early-stage tumors or in combination with chemotherapy in advanced-stage disease. Hyperfractionation has shown a marked improvement in the treatment outcomes including overall survival, yet it inevitably brought challenging difficulties in its implementation into clinical practice. On the other hand, acceleration by moderate hypofractionation offers a practical option in the shortening of the overall treatment time and novel technologies utilization. Adding chemotherapy to radiotherapy is strongly supported by evidence. However, meta-analyses of randomized studies showed a significant improvement in overall survival for concomitant administration for chemotherapy only. Induction chemotherapy with the established standard regimen remains a valid option for selected patients. A standard in concomitant chemotherapy regimen has not been established yet, despite the fact that the pivotal role of cisplatin has been defined as a preferred option in all eligible patients by meta-analyses and randomized studies. Yet, some issues regarding the optimal administration frequency and the optimal total dose persist. Unfortunately, there is no principal direct randomized comparison between the administration of cisplatin 100 mg/m2 every three weeks and weekly cisplatin 40 mg/m2 in primary radiotherapy setting yet. Moreover, the total cisplatin dose above 200 mg/m2 may not be necessary in many case scenarios. The choice of optimal cisplatin dose and administration is further complicated by favorable course of human papilloma virus associated oropharyngeal carcinoma that might be managed with less intensive interventions than other HNSCC. Various aspects of cisplatin administration frequency and dose are discussed in the article. Novel technologies have re-shaped our radiotherapy planning and delivery practice making it more effective and causing less late toxicity. Clinical significance of dosimetric performance comparison of various types of technologies, including proton radiotherapy, remains difficult to estimate. Timely access to high quality standard irradiation, nowadays represented in most cases by intensity modulated radiotherapy, is of higher importance than any specific novel technology for HNSCC patients.

Keywords: squamous cell carcinoma of the head and neck, radiotherapy fractionation, intensity modulated radiotherapy, cisplatin