This phase III trial compares the effect of giving triptorelin vs no triptorelin in preventing ovarian damage in adolescents and young adults (AYAs) with cancer receiving chemotherapy with an alkylating agents. Alkylating agents are part of standard chemotherapy, but may cause damage to the ovaries. If the ovaries are not working well or completely shut down, then it will be difficult or impossible to get pregnant in the future. Triptorelin works by blocking certain hormones and causing the ovaries to slow down or pause normal activity. The triptorelin used in this study stays active in the body for 24 weeks or about 6 months after a dose is given. After triptorelin is cleared from the body, the ovaries resume normal activities. Adding triptorelin before the start of chemotherapy treatment may reduce the chances of damage to the ovaries.

Patients will be registered prior to, during or at the completion of neoadjuvant chemotherapy (Paclitaxel 175 mg/m2 IV over 3 hours and Carboplatin AUC 6 IV on Day 1 every 21 days for 3-4 cycles). Registered patients who progress during neoadjuvant chemotherapy will not be eligible for iCRS and will be removed from the study.

Following completion of neoadjuvant chemotherapy, interval cytoreductive surgery (iCRS) will be performed in the usual fashion in both arms. Patients will be randomized at the time of iCRS (iCRS must achieve no gross residual disease or no disease \>1.0 cm in largest diameter) to receive HIPEC or no HIPEC. Patients randomized to HIPEC (Arm A) will receive a single dose of cisplatin (100mg/m2 IP over 90 minutes at 42 C) as HIPEC. After postoperative recovery patients will receive standard post-operative platinum-based combination chemotherapy. Patients randomized to surgery only (Arm B) will receive postoperative standard chemotherapy after recovery from surgery.

Both groups will receive an additional 2-3 cycles of platinum-based combination chemotherapy per institutional standard (Paclitaxel 175 mg/m2 IV over 3 hours and Carboplatin AUC 6 IV on Day 1 every 21 days for 2-3 cycles) for a maximum total of 6 cycles of chemotherapy (neoadjuvant plus post-operative cycles) followed by niraparib individualized dosing until progression or 36 months (if no evidence of disease).