Hyperfractionated Externally Irradiated Primary Oral Squamous Cell Carcinomas: Vital Tumor Cells in Resection Specimens

Abstract

Oral squamous cell carcinoma (OSCC) is among the most frequent malignancies worldwide. Ablative surgery for OSCC is the therapy of choice, however, severe disfigurement and loss of function is a consequence of therapy. On the other hand, R0-resection margins following ablative surgery do not guarantee disease-free survival, in particular due to the widespread, interconnecting lymphatic vessels. Therefore, irradiation of the primary and efferent lymphatics is a valuable therapeutic alternative to surgery. The combination of both irradiation and surgery might even improve overall survival. It has been argued that curatively planned irradiation (isodose of the primary: 60-70 Gy) might not routinely be followed by ablative surgery. Indeed, the sequelae of surgery in an irradiated field are well known. The aim of this study was to determine vital tumor cells in the resection specimens of irradiated advanced stage OSCC in order to estimate the effect of radiotherapy. Materials and Methods: One hundred patients (male 78, female: 22, mean age 60.2 years) with primary OSCC (T2: n=41, T3: n=26; T4: n=33) and suspected regional lymph node metastases were externally irradiated up to a total dosage of 70 Gy (single dose 1.4 Gy, twice daily, minimum daily interval 6 hours; 5 days a week). Ablative surgery followed radiotherapy about 3 months later. Results: In 51% of the primaries, specimens showed vital tumor cells after completion of radiotherapy. The evidence of vital tumor cells increased with T-stage and with N-stage, but showed no correlation to grading. Conclusion: Irradiation of the head and neck region following a hyperfractionation scheme for the treatment of advanced stage OSCC offers a 50% chance of deletion of malignant cells. Despite high total dosages and sophisticated irradiation protocols, the number of patients with vital tumor cells is high. Short-term follow-up controls are mandatory in patients who were subjected to a primary radiotherapy. Ablative surgery following irradiation is a salvage option for pre-irradiated OSCC patients.