Olfactory neuroblastoma: the University of Erlangen-Nuremberg experience 1975-2000.

Objective: Olfactory neuroblastoma constitutes a rare and, in clinical terms, biologically variable tumor of the nasal cavity, paranasal sinuses, and the base of the skull and presents a challenge to a modern multidisciplinary therapy. Generally acknowledged prognostic factors and a standard therapy fail to exist.
Methods: Between 1975 and 2000 we diagnosed and treated 26 patients with an olfactory neuroblastoma. According to Kadish's classification, 1 patient (4%) showed stage A, 16 patients (53%) stage B, and 11 cases (43%) stage C. Hyams grading was established in 81% of all cases. Fifty-two percent were thus classified as low-grade and 48% as high-grade tumors. Surgical therapy was performed on 23 patients (88.5%), surgery being the exclusive form of therapy (monotherapy) in 5 of these patients. Combined therapy was carried out in 18 cases (surgery, radiotherapy, chemotherapy).
Results: Currently, 16 of 26 treated patients (61.5%) are alive. The disease-specific 10- and 15-year survival determined according to Kaplan-Meier is 76.2%. Fifteen-year survival amounts to 86.7% for smaller tumors (Kadish A/B) and 63.6% for advanced tumors (Kadish C). Seven (26.9%) of the overall group of treated patients developed a recurrence. Salvage therapy was successful in 60% (3 of 5 patients). Fifteen-year survival following salvage therapy amounts to 60%. Patients with high-grade tumors exhibit a significantly reduced 10-year survival (40%) compared to patients with low-grade tumors (100%).
Conclusions: The therapy of olfactory neuroblastoma calls for an interdisciplinary multimodal therapeutic strategy, particularly in the case of advanced tumors. Tumor staging and histopathologic grading according to Hyams are important factors for survival and prognosis. Aggressive salvage therapy can lead to a distinct improvement of long-term survival.