PURPOSE: To examine in retrospect prognostic factors influencing meningeal dissemination relapse of @entity2946 ( @entity2946 ) and to estimate time parameter gamma/alpha of the biologically effective dose for fractionated craniospinal irradiation (CSI). MATERIALS AND METHODS: Fifty-eight @entity1 with @entity2946 who had been treated at our six hospitals from 1980 to 1990, were analyzed by the proportional hazards model consisting of radiation factors of both CSI and @entity2631 ( @entity2631 ), sequential CSI time-lag, and eight non-radiation factors (gender, age, performance status, T-stage, dissemination score, extent of resection, and use of chemotherapy and immunotherapy). The gamma/alpha for CSI was estimated by the profile likelihood method using the maximum value of conditionally calculated time-incorporated biologically effective dose, tBEDmax, of the field treated with the least dose. RESULTS: Dissemination relapse was seen in 23 (40%) @entity1 . Nineteen disseminations occurred within four years, and the cumulative dissemination-free rate was 64% at five years. The site of initial dissemination relapse was both cranial and spinal in 13 @entity1 (57%). Dissemination relapse was accompanied with @entity177 in 43% (10/23) of @entity1 , and four of them were seen later than four years. In the multivariate analysis, significant prognostic factors were dissemination score (p=0.0008) and total dose of CSI (p=0.018). The estimate of gamma/alpha for CSI was about 0.2 Gy/day in BED units. In another multivariate analysis including the best-fitted tBEDmax, significant prognostic factors were dissemination score and the tBEDmax of both CSI (p=0.021) and @entity2631 (p=0.024). CONCLUSION: This analysis indicated that the dissemination score, total dose of CSI, and tBEDmax of both CSI and @entity2631 were significantly prognostic for dissemination relapse of @entity2946 . The estimate of gamma/alpha for CSI was smaller than that derived from our previous analysis for @entity2631 . However, in order to estimate the time factor for CSI more precisely, a larger group of @entity1 treated with concurrent CSI is needed.

Multivariate analysis of dissemination relapse of XXXX and estimation of its time parameter for craniospinal irradiation.

@entity1 :: ('9606', 'Species') :: ['patients'] @entity177 :: ('MESH:D051437', 'Disease') :: ['local failure'] @entity2946 :: ('MESH:D008527', 'Disease') :: ['medulloblastoma', 'MB'] @entity2631 :: ('MESH:D012594', 'Disease') :: ['local irradiation', 'LI']
@entity2946 :: (MESH:D008527,Disease) :: ['medulloblastoma']
