Atypical teratoid rhabdoid tumor in a lower middle-income country: Challenges to cure

Atypical teratoid rhabdoid tumor (ATRT) is a rare type of potentially fatal childhood brain tumor. The present study aimed to examine the overall survival (OS) and event-free survival (EFS) outcomes of pediatric patients with ATRT and to analyze the impact of different prognostic factors, including age, sex, tumor site and size, metastatic disease, the extent of resection, radiotherapy, and chemotherapy, on survival. The present study included 47 patients with ATRT treated at the Children's Cancer Hospital of Egypt (Cairo, Egypt) between July 2007 and December 2017. These patients were treated according to the Dana-Farber Cancer Institute protocol 02-294 for 51 weeks. Various prognostic factors, including age, sex, tumor size and initial metastatic status, exhibited no impact on the radiological response measured at 6 weeks and at the end of treatment. The primary tumor site significantly affected the response to treatment at 6 weeks (P=0.008). Toxicity-related mortality occurred in 29.8% of patients. The median duration of the treatment protocol was 66.9 weeks. The duration of treatment was in the present cohort was longer than the actual 51 weeks of the protocol due to prolonged supportive care of the included patients. Patients who encountered toxicity received reduced dose of chemotherapy in the subsequent cycles in the protocol. Age, initial metastatic status, tumor site and resection extent did not significantly affect the patient outcomes. Preoperative tumor size significantly affected the EFS (P=0.03) and OS (P=0.04). Radiotherapy administration significantly affected the OS (P<0.001) and EFS (P<0.001). The median EFS and OS of patients were 9.3 and 10.3 months, respectively. A total of 24 (51.1%) patients exhibited disease progression or recurrence. The progression sites were local (n=6), metastatic (n=9) or both local and metastatic (n=9). The results of the present study demonstrated that the therapeutic regimen should be patient-adjusted to maintain the treatment intensity and avoid toxicity-related mortality. In lower middle-income countries, short and intensified induction followed by consolidation of treatment, either by single or tandem autologous stem cell transplant, is needed to avoid prolonged exposure to myelosuppression and toxicity-related mortality.