Embryonal tumors in the adult population: implications in therapeutic planning

The natural history of neuroectodermal tumors is still debated as far as pr ognostic factors are concerned; the same uncertainty applies to the optimal radiotherapy schedule and even more to the presumptive additive effect of chemotherapy. The rarity of these rumors and the heterogeneity of managemen t make interpretation of literature data also more difficult. We evaluated clinical course in a cohort of 39 patients, including 31 with medulloblasto ma (MB) and 8 with primitive neuroectodermal tumors (PNET). All patients we re treated with radiotherapy, a standardized chemotherapy protocol includin g PCV scheme, and a second-line chemotherapy with cisplatin and etoposide ( VP16) at recurrence. In 27 patients, intrathecal chemotherapy was also deli vered. Median follow-up was 10.8 years. Overall, PNET had a worse outcome a s compared to MB: median survival times were 42.8 vs. 92.6 months, respecti vely (p = 0.05). At 5 years, 45% of MB patients are alive. No significant d ifference in disease-free period was found between patients of different ag e, desmoplastic variant, tumor localization, or extent of surgery. Patients considered to be "high risk" had a significantly shorter disease-free peri od as compared with low-risk patients (27 vs. 54.7 months, p = 0.04). Syste mic or intrathecal chemotherapy did not influence progression-free survival (PFS). However, in the majority of chemotherapy-treated patients, a low-do se craniospinal radiotherapy was also delivered. This combination of treatm ents may have avoided the expected increased percentage of failure. Moreove r, more than half of recurrent patients had a partial response to chemother apy that extended survival for approximately 3 years. Repeated surgery and chemotherapy at recurrence favorably influenced survival time.