A 58-year-old woman with a history of ovarian cancer (stage IIIC, treated with surgery and chemotherapy 2 years ago) presents for follow-up. She is asymptomatic. CA-125 level is 35 U/mL (normal <35 U/mL), and it was 8 U/mL at her last visit 3 months ago. Pelvic ultrasound and CT abdomen/pelvis are unremarkable. What is the most appropriate next step in management?

Explanation

## Clinical Context This patient has a rising CA-125 (from 8 to 35 U/mL, now at the upper limit of normal) but no imaging or clinical evidence of recurrence. The question tests understanding of CA-125 as a surveillance marker and the appropriate response to borderline elevation. ## CA-125 in Ovarian Cancer Surveillance **Key Point:** CA-125 is a sensitive but non-specific marker for ovarian cancer. A single elevated or rising value in the absence of imaging or clinical findings does NOT mandate immediate treatment. **High-Yield:** The NCCN and ASCO guidelines recommend: - CA-125 monitoring during surveillance (every 3–6 months) - Imaging (CT/ultrasound) when CA-125 rises persistently or clinical suspicion increases - Treatment initiation only when recurrence is confirmed by imaging or clinical findings, not by marker elevation alone ## Interpretation of CA-125 Dynamics | Scenario | CA-125 Trend | Imaging | Next Step | |----------|--------------|---------|----------| | Asymptomatic, normal imaging, CA-125 at ULN | Rising slowly | Negative | Continue surveillance | | Asymptomatic, normal imaging, CA-125 markedly elevated | Rapid rise | Negative | Repeat marker + consider diagnostic imaging | | Symptomatic OR imaging positive | Any elevation | Positive | Treat | | Asymptomatic, normal imaging, CA-125 normal | Stable | Negative | Continue surveillance | **Clinical Pearl:** "CA-125 alone does not diagnose recurrence." Many benign conditions (menstruation, endometriosis, infection, other malignancies) can elevate CA-125. In the absence of imaging or clinical findings, rising marker is a signal to intensify surveillance, not to treat. **Mnemonic: "RECUR" — When to Treat Rising CA-125 in Ovarian Cancer** - **R**ising marker trend (2–3 consecutive rises) - **E**vidence on imaging (CT/MRI showing lesion) - **C**linical symptoms (pain, ascites, bowel obstruction) - **U**nequivocal biochemical rise (>2× baseline on repeat testing) - **R**eliable marker kinetics (confirm with repeat in 2–4 weeks) ## Management Algorithm ```mermaid flowchart TD A[Ovarian cancer survivor with rising CA-125]:::outcome --> B{Imaging findings?}:::decision B -->|Positive for recurrence| C[Confirm with repeat imaging]:::action B -->|Negative| D{Clinical symptoms?}:::decision C --> E[Discuss treatment options]:::action D -->|Yes| F[Further diagnostic workup]:::action D -->|No| G{CA-125 markedly elevated or rapidly rising?}:::decision G -->|Yes| H[Repeat CA-125 in 2-4 weeks]:::action G -->|No| I[Continue surveillance q3-6 months]:::action H --> J{Confirmed elevation?}:::decision J -->|Yes| F J -->|No| I ```