The prognostic impact of additional chemotherapy to radiation therapy for postoperative mangement of pediatric medulloblastoma

الملخص EN

Purpose : The aim of this study is to evaluate treatment Results of combined therapy; surgery, postoperative craniospinal Radiotherapy with chemotherapy compared to Treatment with postoperative radiotherapy only.

Also to Assess the effect of extent of surgical resection on prognosis.

Patients and Methods : Between 1993 and 2003, 34 Children >3 years of age with nondisseminated medulloblastoma Were treated with postoperative, craniospinal Radiation therapy (36 Gy in 20 fractions to the craniospinal axis, supplemented by a posterior fossa dose of 1980 cGy in 11 fractions (total dose of 56 Gy).

Daily fractions of 1.8 Gy were used.

Out of them, 16 children received chemotherapy in the form of vincristine, at a dose of 1.5mg / m2, which was given weekly during radiotherapy.

One month after completion of radiation therapy, chemotherapy was continued every 4 weeks with cycles of cyclophosphamide (750mg/m2) and vincristine (2mg/m2) for a maximum dose of 2mg, alternating with vincristine and carboplatin (500mg/m2).

A total of 12 alternating cycles were administered.

Results : The follow-up period ranged from 14-132 months.

The median overall survival (OAS) for the whole group was 49.5 months (mean of 61±38) while the median progression free survival (PFS) was 47.5 months (mean 59.6±39).

Although both PFS and OAS were better among those who had total resection than subtotal resection (estimated 5-y PFS of 60% and 64% for both groups, respectively and estimated 5-y OAS of 65% for subtotal resection and 69% for those underwent total resection), however this difference was not statistically significant (p=0.1).

The median PFS for the chemotherapy group was 60.5 months (Mean was 72.6±41.7) while that for the nonchemotherapy group was 39.5 months (mean 48±33.6).

The difference was of borderline significance with a pvalue of 0.06.

The estimated 5-year progression free survival for the chemotherapy group was 70% while that of no chemotherapy group was 59% with a p-value of .025 While the estimated 5-year overall survival for chemotherapy group was 70% in comparison to 60% for non-chemotherapy group giving borderline statistical significance difference with a p-value of 08.

Conclusion : Maximum possible surgical resection, postoperative radiotherapy and adjuvant chemotherapy are important factors in improving outcome in the management of medulloblastoma.