A 52-year-old woman from Mumbai presents with postmenopausal bleeding and pelvic pain for 4 months. She has a history of Lynch syndrome (MLH1 mutation). Pelvic MRI shows a large endometrial mass with invasion into the outer myometrium and parametrial involvement. Endometrial biopsy confirms grade 3 adenocarcinoma. She is counseled about staging and adjuvant therapy. Which of the following is the MOST appropriate next step in management?

Explanation

## Clinical Context This patient has **Lynch syndrome** (hereditary nonpolyposis colorectal cancer, HNPCC) with an MLH1 mutation, which confers a 40–60% lifetime risk of endometrial cancer. She presents with advanced-stage disease (grade 3, myometrial invasion, parametrial involvement) and requires comprehensive surgical staging and adjuvant therapy. ## Staging and Surgical Management of Endometrial Carcinoma ```mermaid flowchart TD A[Endometrial Carcinoma Diagnosed]:::outcome --> B{Stage Assessment}:::decision B -->|Early stage<br/>No myometrial invasion| C[Simple TAH-BSO]:::action B -->|Intermediate risk<br/>Inner/mid myometrium| D[TAH-BSO + Pelvic lymphadenectomy]:::action B -->|Advanced stage<br/>Outer myometrium/parametrial| E[TAH-BSO + Pelvic + Para-aortic lymphadenectomy]:::action E --> F[Comprehensive Staging]:::outcome F --> G{Adjuvant Therapy?}:::decision G -->|Grade 3 + Advanced| H[Chemotherapy + Radiation]:::action G -->|Grade 1-2 + Early| I[Observation or Radiation]:::action ``` ## Why Comprehensive Surgical Staging is Indicated **Key Point:** This patient has **high-risk features**: - Grade 3 (poorly differentiated) adenocarcinoma - Outer myometrial invasion (stage IB) - Parametrial involvement (stage II) - Lynch syndrome (MSI-H phenotype) **High-Yield:** The standard of care for **stage II–III endometrial carcinoma** is: 1. **Total abdominal hysterectomy (TAH)** with **bilateral salpingo-oophorectomy (BSO)** 2. **Pelvic and para-aortic lymphadenectomy** (comprehensive staging) 3. **Adjuvant chemotherapy** (platinum-based, e.g., carboplatin + paclitaxel) followed by **radiation** (external beam ± brachytherapy) **Clinical Pearl:** Lynch syndrome patients with endometrial cancer have MSI-H tumors, which are: - Responsive to checkpoint inhibitor immunotherapy (pembrolizumab) - Eligible for adjuvant chemotherapy + radiation as standard - At higher risk for synchronous or metachronous colorectal cancer (requires colonoscopy surveillance) ## Why Neoadjuvant Chemotherapy is NOT Standard **Warning:** Neoadjuvant chemotherapy is **not** the primary approach for resectable endometrial cancer. It may be considered in **unresectable or metastatic disease**, but this patient has locally advanced disease amenable to primary surgery. ## Adjuvant Therapy Rationale | Feature | Implication | |---------|-------------| | Grade 3 | High risk for recurrence | | Outer myometrial invasion | Stage IB; requires lymphadenectomy | | Parametrial involvement | Stage II; requires combined modality therapy | | Lynch syndrome (MSI-H) | Favorable response to immunotherapy; also eligible for chemoradiation | **Mnemonic:** **STAMP** — **S**urgery (TAH-BSO + lymphadenectomy), **T**esting (comprehensive staging), **A**djuvant (chemotherapy + radiation), **M**ultidisciplinary (gynecologic oncology), **P**rognosis (intermediate-to-poor without treatment).