Should a patient with recurrent High-Grade Serous Carcinoma (HGSC) at 6 months undergo a full body Computed Tomography (CT) scan to check for metastases to bones?

Imaging for Recurrent High-Grade Serous Carcinoma at 6 Months

Yes, perform comprehensive restaging imaging including CT chest/abdomen/pelvis with contrast, but bone-specific imaging (bone scan or full body CT specifically for bone metastases) should only be added if the patient has bone pain, elevated bone-specific biomarkers, or other clinical signs suggesting skeletal involvement.

Rationale for Comprehensive Restaging

Recurrent HGSC at 6 months represents aggressive disease requiring full restaging to guide treatment decisions that impact survival and quality of life. 1

• ESMO guidelines for breast cancer (which shares similar metastatic patterns with ovarian HGSC) explicitly recommend full re-staging including bone imaging in patients with recurrence, given the high risk of concomitant distant metastases 1
• The standard approach for recurrent disease involves thoracic and abdominal CT as the preferred modality over plain radiography 1

Bone Metastasis Screening Strategy

When Bone Imaging IS Indicated:

• Symptomatic patients: Bone scintigraphy or radiography should be performed in all patients with signs and symptoms of bone metastases, including localized bone pain 1
• Biochemical indicators: Elevated bone-specific alkaline phosphatase (B-ALP) suggests bone involvement 1
• High-risk features: Patients with aggressive tumor biology warrant consideration of bone imaging 1

When Routine Bone Imaging is NOT Indicated:

• Asymptomatic patients: Multiple ESMO guidelines across tumor types (renal cell carcinoma, prostate cancer) recommend bone scintigraphy only when indicated by clinical or laboratory signs, not routinely 1
• Bone scan has limited utility in asymptomatic surveillance, with sensitivity of only 86% and specificity of 81% 2

Optimal Imaging Approach for HGSC Recurrence

Primary Imaging Modality:

• Contrast-enhanced CT of chest, abdomen, and pelvis is the cornerstone for restaging 1
• This captures the most common metastatic sites for HGSC: peritoneum, liver, lymph nodes, and pleura 3

Advanced Imaging Considerations:

• PET/CT with 18FDG may be used instead of (not in addition to) CT and bone scintigraphy when conventional methods are inconclusive 1
• PET/CT demonstrates superior sensitivity (90%) and specificity (97%) for metabolically active disease compared to bone scintigraphy 2
• Whole-body MRI offers superior sensitivity (91%) and specificity (95%) for bone marrow metastases compared to bone scintigraphy, and is more sensitive than PET-CT for detecting small bone lesions (detection threshold 2mm vs 5mm) 2, 4

Clinical Algorithm

For asymptomatic recurrence at 6 months:

1. Obtain contrast-enhanced CT chest/abdomen/pelvis as primary restaging tool 1
2. Assess for bone pain, elevated B-ALP, or other skeletal symptoms 1
3. If symptomatic or biochemical evidence exists: add bone scintigraphy or consider PET/CT 1
4. If CT findings are equivocal: proceed to PET/CT or whole-body MRI 1, 4

For symptomatic recurrence:

1. Full restaging with contrast-enhanced CT chest/abdomen/pelvis 1
2. Add bone-specific imaging (bone scan, PET/CT, or MRI) regardless of location of symptoms 1
3. Consider PET/CT as single comprehensive study combining anatomical and metabolic information 1, 2

Important Caveats

• Early recurrence (6 months) indicates aggressive biology and warrants comprehensive evaluation rather than limited imaging 3
• Bone scintigraphy has lower cost and greater availability than PET/CT or whole-body MRI, but inferior sensitivity for early or small metastases 1
• CT alone may miss bone marrow involvement without cortical destruction 2, 4
• The pattern of metastatic spread in HGSC typically involves peritoneal surfaces first, with bone metastases being less common than in breast or prostate cancer 5, 6