What is the recommended treatment approach for a patient with a history of uterine cancer now presenting with a pelvic mass suspicious of metastatic disease?

Recommended Treatment Approach for Suspected Metastatic Uterine Cancer with Pelvic Mass

For a patient with history of uterine cancer presenting with a pelvic mass suspicious for metastatic disease, you must first obtain tissue confirmation via biopsy before initiating any systemic therapy, followed by comprehensive staging imaging to determine the extent of disease and guide treatment selection between surgical debulking versus systemic therapy. 1, 2

Initial Diagnostic Workup

Imaging for Metastatic Disease

• Obtain chest/abdomen/pelvis CT with IV contrast OR FDG-PET/CT of neck/chest/abdomen/pelvis to evaluate for distant metastases 1
• CT is the primary modality for staging and follow-up of suspected metastatic gynecologic malignancies 1
• MRI pelvis with contrast can serve as a problem-solving tool if CT findings require further characterization 1

Tissue Confirmation is Mandatory

• Biopsy of the pelvic mass must be performed to confirm recurrent/metastatic disease before changing treatment intent 2
• Core needle biopsy under image guidance (ultrasound or CT) is the standard approach, with multiple cores taken to maximize diagnostic yield 3, 2
• Do not initiate systemic therapy based on imaging findings alone, as false-positive results could lead to unnecessary treatment with significant toxicity 2

Laboratory Evaluation

• Measure CA-125 levels, as this is recommended for stage III or IV endometrioid tumors 1
• Obtain complete blood count and comprehensive metabolic panel including liver and renal function 3
• Consider ER/PR testing on biopsy specimen, as this is recommended for stage III/IV endometrioid tumors and may guide hormonal therapy options 1

Treatment Algorithm Based on Disease Extent

For Abdominal/Pelvic-Confined Disease

• Surgical intervention with total hysterectomy/bilateral salpingo-oophorectomy (TH/BSO), surgical staging, and surgical debulking with the goal of no measurable residual disease is recommended 1
• Multiple studies support cytoreductive surgery for confined metastatic disease 1
• Consider preoperative chemotherapy in select cases 1

For Distant Visceral Metastases

• Systemic therapy is the primary treatment approach, with or without external beam radiation therapy (EBRT), and with or without TH/BSO 1
• Stereotactic body radiation therapy (SBRT) can be considered for 1-5 metastatic lesions if disease is otherwise controlled (category 2B) 1
• Ablative radiation is an option for oligometastatic disease 1

For Disease Not Suited for Primary Surgery

• EBRT and/or brachytherapy is the preferred treatment approach 1
• Systemic therapy alone is also a primary treatment option (category 2B), but should be followed by EBRT plus brachytherapy if the patient remains inoperable 1
• Progestational agents (medroxyprogesterone acetate or megestrol acetate) may be considered as alternatives 1

Systemic Therapy Considerations

Chemotherapy Options

• While the provided guidelines focus primarily on vulvar cancer systemic regimens, extrapolation to endometrial cancer suggests platinum-based combinations are appropriate 1
• Patients with isolated pulmonary metastases may have prolonged survival (36.1 months) whether treated medically or surgically 4

Hormonal Therapy

• Progestin therapy can achieve complete response (radiographic resolution) in 15% of patients with pulmonary metastases and prolonged stabilization in an additional 13% 4
• Low-grade uterine tumors are more likely to respond to progestin therapy for extended periods 4
• ER/PR status should guide consideration of hormonal therapy 1

Critical Pitfalls to Avoid

Diagnostic Errors

• Never proceed with systemic therapy or change treatment intent from curative to palliative without tissue confirmation 2
• Failing to perform appropriate imaging before biopsy may compromise treatment planning 3
• Do not rely solely on imaging findings, as PET/CT has limited specificity (79%) with false-positives occurring in inflammatory conditions 2

Treatment Planning Errors

• Avoid intraperitoneal morcellation when removing endometrial carcinoma, as it should be removed en bloc to optimize outcomes 1
• Do not assume all pelvic masses in patients with uterine cancer history are metastatic—benign processes and second primary malignancies must be excluded 5, 6
• For patients with incomplete surgical staging and high-risk features, additional imaging or surgical restaging should be considered before finalizing adjuvant treatment plans 1

Prognosis and Surveillance

• Patients with isolated pelvic metastases have better outcomes than those with distant or multiple-site disease 1
• The majority of patients (75%) with pulmonary metastases from uterine cancer do not survive 1 year, though 6% survive more than 5 years 4
• Tumor grade is predictive of response to hormonal therapy, with low-grade tumors showing better responses 4