Why is a chest X‑ray performed in the initial evaluation of newly diagnosed endometrial cancer?

Why Chest X-Ray is Performed in Endometrial Cancer Evaluation

Chest X-ray is performed during the initial evaluation of newly diagnosed endometrial cancer to screen for pulmonary metastases, which—though rare in low-risk disease—can alter staging, surgical planning, and adjuvant treatment decisions.

Guideline-Based Rationale

The primary purpose of chest imaging in endometrial cancer workup is to detect distant metastatic disease that would upstage the patient and fundamentally change management 1, 2.

Risk-Stratified Imaging Approach

For low-risk patients (grade 1-2 endometrioid histology, no clinical evidence of extrauterine spread):

• Chest X-ray is the appropriate screening modality 3
• The incidence of pulmonary metastases in this population is exceptionally low (0% in one institutional series of 228 patients; 95% CI 0%-2%) 3
• False-positive findings requiring follow-up imaging occur in approximately 8.8% of cases 3

For high-risk patients (grade 3, non-endometrioid histology, serous or clear cell carcinoma, or clinical suspicion of extrauterine disease):

• Chest CT (as part of thoracic and abdominal CT) is preferred over plain radiography 1, 2
• Additional imaging with FDG-PET/CT may be considered for detecting distant metastases, given its high specificity and positive predictive value 1
• All patients with confirmed pulmonary metastases—either at presentation or recurrence—demonstrate high-risk tumor features 3

Historical Context and Current Practice

Chest X-ray has been advocated as part of the standard metastatic workup alongside careful pelvic examination since at least the 1980s 4. However, contemporary guidelines recognize that additional imaging tests (including thoracic CT) should be reserved for patients at high risk of extrapelvic disease rather than applied universally 1.

Detection Rates and Clinical Utility

• The overall incidence of pulmonary metastases detected on preoperative imaging across all risk groups is approximately 1.3% 3
• For asymptomatic chest recurrences detected on surveillance chest radiographs, detection rates range only from 0% to 20% 2
• When pulmonary metastases are present, they typically occur in the context of other high-risk features (deep myometrial invasion, cervical stromal involvement, lymph node metastases) 3

Impact on Surgical Planning

Identification of extrauterine metastases or spread on preoperative imaging helps determine the surgical approach 2:

• Laparotomy is preferred when involvement of pelvic or abdominal organs is suspected 2
• Minimally invasive surgery remains appropriate for patients without evidence of advanced disease 2

Common Pitfalls

Avoid ordering chest CT routinely in low-risk patients, as this leads to unnecessary radiation exposure, false-positive findings requiring additional workup, and increased healthcare costs without improving outcomes 3. The 8.8% false-positive rate with initial imaging in low-risk patients underscores this concern 3.

Do not rely on chest X-ray alone in high-risk histologies (serous, clear cell, carcinosarcoma, grade 3 endometrioid), as these warrant more comprehensive staging with cross-sectional imaging 1, 2.