4012 - Can we cure patients with abdominal Desmoplastic Small Round Cell Tumor? Results of a retrospective multicentric study on 100 patients.

Background

Desmoplastic Small Round Cell Tumor (DSRCT) is a rare peritoneal disease affecting children and young adults. Despite a very poor prognosis, long-term survivors have been reported. the aim of the study is to identify in a nation-wide survey patients with a prolonged survival after DSRCT diagnosis and to identify factors associated with a cure.

Methods

All consecutive patients treated for DSRCT in 9 French expert centers between 1991 and 2018 were identified and retrospectively analyzed. Patients with a follow-up of less than 2 years were excluded from the analysis. Cure was defined as a disease-free survival of at least 5 years.

Results

100 pts were identified (median age 25, 89% male). 27 had distant metastases at diagnosis. 80 pts underwent upfront chemotherapy and 51 pts were subsequently operated. 20 pts went directly to surgery. Surgery was macroscopically complete (CC0/1) in 50 pts. Intraperitoneal chemotherapy was associated to surgery in 17 pts. 54 pts had postoperative chemotherapy and 26 pts had postoperative whole abdomino-pelvic RT (WAP-RT). After a median follow-up of 124 months (range 23-311), the median overall survival (OS) was 25 months. 1- year, 3-year and 5-year OS rates were 90%, 35% and 4% respectively. 7 patients were considered cured after a median disease-free interval of 100 months (range 22-139). Predictive factor of cure were female sex (HR = 4.46, p = 0.005), median PCI<12 (HR = 4.53, p = 0.005), MD Anderson stage I (HR = 3.97, p = 0.003), CC0/1 (HR = 2.17, p = 0.05) and WAP-RT (HR = 3.41; p = 0.003). Neither Hyperthemic intraperitoneal chemotherapy (HIPEC) nor early postoperative intraperitoneal chemotherapy (EPIC) did increase the rate of cure.

Conclusions

Cure in DSRCT is possible in 7% of patients and is best achieved combining systemic chemotherapy, complete cytoreductive surgery and WAP-RT. Targeted treatments are urgently needed.

Clinical trial identification

Legal entity responsible for the study

Gustave Roussy.

Funding

Has not received any funding.

Editorial Acknowledgement

Disclosure

All authors have declared no conflicts of interest.