Abdominal desmoplastic small round cell tumor without extraperitoneal metastases: Is there a benefit for HIPEC after macroscopically complete cytoreductive surgery?

BACKGROUND Desmoplastic Small Round Cell Tumor (DSRCT) is a rare disease affecting predominantly children and young adults and for which the benefit of hyperthermic intraperitoneal chemotherapy (HIPEC) after complete cytoreductive surgery (CCRS) remains unknown. METHODS To identify patients with DSRCT without extraperitoneal metastases (EPM) who underwent CCRS between 1991 and 2015, a retrospective nation-wide survey was conducted by crossing the prospective and retrospective databases of the French Network for Rare Peritoneal Malignancies, French Reference Network in Sarcoma Pathology, French Sarcoma Clinical Network and French Pediatric Cancer Society. RESULTS Among the 107 patients with DSRCT, 48 had no EPM and underwent CCRS. The median peritoneal cancer index (PCI) was 9 (range: 2-27). Among these 48 patients, 38 (79%) had pre- and/or postoperative chemotherapy and 23 (48%) postoperative whole abdominopelvic radiotherapy (WAP-RT). Intraperitoneal chemotherapy was administered to 11 patients (23%): two received early postoperative intraperitoneal chemotherapy (EPIC) and nine HIPEC. After a median follow-up of 30 months, the median overall survival (OS) of the entire cohort was 42 months. The 2-y and 5-y OS were 72% and 19%. The 2-y and 5-y disease-free survival (DFS) were 30% and 12%. WAP-RT was the only variable associated with longer peritoneal recurrence-free survival and DFS after CCRS. The influence of HIPEC/EPIC on OS and DFS was not statistically conclusive. CONCLUSION The benefit of HIPEC is still unknown and should be evaluated in a prospective trial. The value of postoperative WAP-RT seems to be confirmed.