Is endometrial cancer associated with metastasis (mets) to the lungs?

Endometrial Cancer Metastasis to the Lungs

Yes, endometrial cancer is strongly associated with metastasis to the lungs, which is the most common site of extraperitoneal metastasis in endometrial cancer patients. 1

Pattern of Metastatic Spread in Endometrial Cancer

Endometrial cancer typically follows a predictable pattern of spread:

1. Local spread: Initially confined to the uterus (75% of cases at diagnosis) 1
2. Regional spread: Pelvic and para-aortic lymph nodes
3. Distant metastasis: When extraperitoneal metastasis occurs, the lungs are the primary target

According to the ACR Appropriateness Criteria, extrapelvic recurrence of endometrial cancer commonly involves the peritoneum and lungs, followed by atypical sites including extra-abdominal lymph nodes, liver, adrenals, brain, bones, and soft tissue 1.

Epidemiology and Risk Factors

The lung is the most common site of extraperitoneal metastasis in endometrial cancer:

• 50.96% of patients with extraperitoneal metastasis have single lung metastases
• 26.85% have multiple organ metastases that include pulmonary invasion 2

Independent risk factors for extraperitoneal metastasis include:

• Grade 3 tumors (odds ratio = 3.39)
• Positive peritoneal cytology (odds ratio = 2.02)
• Cervical stromal invasion (odds ratio = 1.42) 2

Metastatic Mechanisms

Several pathological features predict the likelihood of distant metastasis:

1. Lymphovascular space involvement (LVSI): The strongest predictor of distant metastases, particularly when assessed by immunohistochemistry with antibodies against factor VIII-related antigen or CD31 3

2. Depth of myometrial invasion: Deeper invasion correlates with higher risk of lymphatic spread and subsequent distant metastasis 3

3. Histological subtype: Endometrioid and clear cell carcinomas typically metastasize hematogenously to the lungs, bones, liver, and brain. Serous carcinomas tend to show extensive peritoneal spread 3

4. MELF pattern: Microcystic, elongated, and fragmented glandular invasion pattern predicts lymph node metastases, which can lead to distant spread 3

Imaging and Detection

For patients with endometrial cancer, imaging of the chest may be indicated in selected high-risk, advanced-stage patients to detect lung metastasis 1. According to FIGO staging, distant metastases including to the lungs are classified as stage IVB 1.

Radiologic evaluation such as CT scan or FDG-PET/CT scan of the chest, abdomen, and pelvis should be used to investigate suspicion of recurrent disease rather than for routine surveillance after treatment 1.

Prognostic Implications

The presence of lung metastases significantly impacts prognosis:

• Median cancer-specific survival for patients with solitary pulmonary metastasis: 23 months (with surgery) vs. 9 months (without surgery) 2
• Multiple organ metastases including lung: 15 months (with surgery) vs. 4 months (without surgery) 2

Management Considerations

For patients with lung metastases from endometrial cancer:

1. Surgical intervention: Surgery for the primary tumor appears to improve survival in patients with lung metastases (median survival 23 vs. 9 months) 2

2. Systemic therapy: Platinum-based chemotherapy is recommended for advanced disease 4

3. Surveillance: Most recurrences occur within the first 3 years after treatment, requiring vigilant follow-up during this period 4

Clinical Implications

Understanding the association between endometrial cancer and lung metastasis is crucial for:

• Appropriate staging workup in high-risk patients
• Surveillance planning after primary treatment
• Early detection of recurrence
• Treatment planning for metastatic disease

In summary, the lungs represent the most common site of extraperitoneal metastasis in endometrial cancer, and clinicians should maintain a high index of suspicion, particularly in patients with high-grade tumors, deep myometrial invasion, and lymphovascular space involvement.