Objective: We intended to assess the clinicopathological features and treatment outcome in patients of intracranial atypical teratoid rhabdoid tumor (AT/RT), a rare malignant tumor of the brain.
Methods: Medical records were reviewed and clinical data collected on AT/RT in a 6-year period (2006-2012). Overall survival was analyzed by Kaplan-Meier method. Univariate analysis of factors predictive of overall survival was done by log-rank test.
Results: Fifteen patients met the study criterion (male:female = 4:1). Median age at presentation was 5 years (range, 0.8-8 years). Presenting complaints included vomiting (73.33 %), headache (46.67 %), orbital symptoms (33.33 %), motor impairment (26.67 %), gait abnormality (20 %), and seizure (20 %). Median duration of symptoms was noted to be 2 months (range, 0.5-6 months). On contrast-enhanced MRI of brain, tumor location was supratentorial in 60 % patients and infratentorial in 40 % of patients. Cystic component and hydrocephalus were noted in 73.33 % patients each, whereas contrast enhancement and calcification were discerned in 53.33 and 40 % of the patients, respectively. All patients underwent tumor resection-gross total (26.67 %), near-total (13.33 %) and subtotal (60 %). Histopathology was confirmative of AT/RT with MIB-1 labeling index varying from 11 to 85 % (median 45 %). There was a lack of immunostaining for INI-1 protein, suggesting INI-1gene mutation or deletion. Adjuvant radiation (36 Gray/20 fractions/4 weeks to entire neuraxis followed by local boost 20 Gray/10 fractions/2 weeks) was started in six patients (40 %) and completed in five patients. Young age at presentation and poor performance status precluded the use of radiation in the remainder. Systemic chemotherapy was administered in ten (66.67 %) patients. Median number of cycles given was three (range, 1-12) with ICE (ifosfamide, carboplatin, etoposide) and VAC (vincristine, dactinomycin, cyclophosphamide) being the common regimens (26.67 and 20 %, respectively). After a median follow-up of 8.33 months (mean, 12.27 months), median overall survival was noted to be 10 months. At last follow-up, two patients are in complete response, one patient is on treatment, three patients are alive with evidence of disease, and nine patients expired due to disease progression. The 1- and 2-year actuarial rate of overall survival was noted to be 48.1 and 24.1 %, respectively. On univariate analysis, extent of surgery (p = 0.0149), use of craniospinal radiation (p = 0.0087), and MIB1 labeling index (p = 0.0034) were significant predictors of overall survival while age (≥5 years versus <5 years) was of borderline significance (p = 0.08).
Conclusions: Median survival of 10 months reflects the aggressive biology of this rare neoplasm. Maximal safe resection followed by craniospinal irradiation and systemic chemotherapy with ICE or VAC regimen is a reasonable treatment strategy in this uncommon malignancy.