Management of Suspected Stage IVA Endometrial Cancer With Rectosigmoid Involvement Using Neoadjuvant Chemotherapy and Interval Surgery.

Stage IVA endometrial cancer with rectosigmoid involvement is rare and presents challenges for primary surgical management due to the risk of major multivisceral resection and associated morbidity. We report the case of a 55-year-old woman who presented with prolonged postmenopausal bleeding, foul-smelling vaginal discharge, and pelvic pain. Imaging showed a large pelvic mass inseparable from the rectum and sigmoid colon. Histopathology demonstrated a moderately differentiated adenocarcinoma of gynaecological origin that was mismatch repair-proficient and p53 wild-type. In view of the extent of local disease and the anticipated morbidity of primary surgery, the multidisciplinary team (MDT) recommended neoadjuvant chemotherapy (NACT). The patient experienced rapid symptomatic improvement following the first cycle of NACT. Baseline cross-sectional imaging demonstrated a large pelvic mass measuring 14x10 cm, with suspected rectosigmoid involvement and suspicious pelvic lymphadenopathy. Following four cycles of chemotherapy, repeat imaging showed a marked reduction in tumour size consistent with a partial radiological response according to RECIST 1.1 (Response Evaluation Criteria in Solid Tumours version 1.1) criteria. No progressive nodal disease was identified. In view of the favourable radiological and clinical response, minimally invasive interval surgery was planned with the primary aim of assessing disease resectability, with the intention to proceed with cytoreductive surgery only in the absence of widespread peritoneal disease. Interval laparoscopic hysterectomy and bilateral salpingo-oophorectomy were subsequently performed. Intraoperatively, dense fibrosis and tissue friability were encountered, consistent with chemotherapy response. There was no macroscopic peritoneal disease, and no evidence of true rectosigmoid invasion; therefore, bowel resection was not required. Final histopathology demonstrated only focal residual adenocarcinoma involving the endometrium and cervix with clear margins. The patient received one further cycle of chemotherapy postoperatively and is currently awaiting adjuvant radiotherapy. She remains symptom-free at follow-up. This case highlights the role of NACT in selected patients with locally advanced endometrial cancer, where primary surgery carries high morbidity. It demonstrates that endometrioid carcinomas can achieve meaningful clinical and pathological responses, enabling interval surgery in advanced-stage disease through careful MDT-led decision-making.