20-Year Follow-up of 52 Patients with Advanced Tumors of the Anterior Skull Base Treated with Intraoperative Radiotherapy

Introduction: An interdisciplinary treatment approach is necessary to achieve local tumor control in advanced primary and recurrent tumors of the anterior skull base. Over the past 20 years, we have investigated the use of intraoperative radiotherapy in the area of the complex skull base anatomy and whether this therapy modality leads to an improvement in local tumor control and long term survival.

Methods: After local tumor removal at the anterior skull base, 52 patients underwent intraoperative radiotherapy (41 males and 11 females age 35–73). In 32 patients primary tumor was present, and in 20 patients treatment was performed due to a local recurrence. Electrones with energy levels of 4 and 6 MeV (Mega Electrone Volt) were applied and a Maximum dose of 10 Gray (8–10 Gy) was given. Perspex tubes with a diameter of 4 and 5 cm were used to focus the dose. 37 patients also received adjuvant radiotherapy. The most common anatomic regions in our patients involved the paranasal sinuses (27 primary, 5 recurrent tumors) followed by the nasal cavity (7), buccal mucosa (3), orbita (3), nasopharynx (2), oropharynx (2), parotid gland, thyroid carcinoma and recurrence of CUP syndrome, (one patient each). Histologies ranged from squamous cell carcinoma (18 patients) to adenocarcinomas (15 patients), undifferentiated (4 patients) adenoid cystic carcinomas (3 patients), olfactory neuroblastoma (3 patients), mucoepidermoid carcinomas and melanomas (2 patients each) as well as leiomyosarcoma, basal cell carcinoma, transitional cell carcinoma, sebaceous gland carcinoma and papillary thyroid carcinoma (1 patient each).

Results: With a median follow-up time of 6.2 years (0, 1–20), 13 of 32 patients with advanced primary tumor and 7 out of 20 patients with recurrent tumor are alive; of these 20 patients, 14 have a survival time of at least 136 months with local tumor control and without distant metastases. Three other patients are locally tumor-free and without distant metastases (97, 36, 13 months). One patient shows distant metastases at 24 months, 2 patients have distant metastases, and local recurrence (49 and 20 months, respectively).

Conclusion: The cohort of patients with anterior skull base tumors treated with intraoperative radiotherapy in Salzburg is the largest group in the literature in which a long-term follow-up of 20 years has been captured. We could show that the inclusion of intraoperative radiotherapy as an integral component of interdisciplinary treatment is possible and leads to long-term tumor control in one third of patients with high quality of life without the occurrence of significant side effects

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Artikel online veröffentlicht:
15. Februar 2022