Outcome and prognostic factors in metastatic primitive neuroectodermal tumors with uniform chemotherapy protocol: A single center experience of 150 patients.

Abstract

Background: Data on metastatic primitive neuroectodermal tumor (PNET) with uniform protocol is minimal. Methods: This is single institutional patient review treated between June 2003-Nov 2011, and evaluated on intent-to-treat analysis. All patients received uniform chemotherapy (VAC/IE) as follows: neoadjuvant chemotherapy (NACT), surgery and/or radiotherapy as local treatment followed by ACT. Local treatment was offered if patient achieved CR and/or PR at both primary and metastatic site. Results: 150/374 (40%) PNET patients were metastatic with median age 15 years (range: 2–50); tumor diameter 10 cm (range: 1.8-26) and symptom duration 4 months (range: 0.1-30). Most common tumor region was pelvis 34 (23%), thorax 26 (17%) and femur in 26 (17%). Most common metastatic sites were lung only 53 (35%), bone only 35 (23%), combined bone/lung 25(17%), and bone marrow 37 (25%). Post-NACT, 9 (6%) achieved CR and 79 (53%) PR (53%) with ORR 59%. Twenty patients underwent surgery; 55 patients received radical radiotherapy following NACT. At median follow-up of 20.8 months (range: 1.6–95), 5-year EFS, OS and local control rate (LCR) were 7.6%, 15% and 37.6%, respectively. Multivariate analysis of prognostic factors in entire group and lung only metastases group is shown in the Table. Conclusions: This is the largest study of metastatic PNET from Asia and has identified unique prognostic factors. Hypoalbuminemia had inferior EFS; radical radiotherapy had inferior LCR. In group with only lung metastases, age ≤15 years and number of metastases >3 had lower EFS. In view of dismal prognosis with conventional chemotherapy in metastatic PNET, metronomic therapy may be a potential therapeutic alternative for subgroup of metastatic patients with hypoalbuminemia.