When should I schedule follow‑up visits and imaging for my melanoma after completing adjuvant pembrolizumab therapy?

Follow-Up Schedule After Adjuvant Pembrolizumab for Melanoma

After completing 52 weeks of adjuvant pembrolizumab for resected high-risk melanoma, schedule follow-up visits every 3–6 months for the first 2–3 years, then annually, with imaging frequency stratified by stage: stage IIB–IIC patients require clinical examination with selective imaging based on symptoms, whereas stage III patients warrant routine cross-sectional imaging every 6–12 months for the first 2–3 years. 1

Stage-Specific Surveillance Strategy

Stage IIB–IIC Melanoma

• Clinical examination every 3–6 months for years 1–2, then every 6–12 months through year 5 is the cornerstone of surveillance, as physical examination detects the majority of recurrences in this population 2, 3.
• Routine imaging (chest X-ray or CT) is not required for asymptomatic stage IIA–IIB patients, as surveillance imaging did not improve survival compared to physical examination alone in retrospective cohorts 2.
• For stage IIC disease specifically, consider whole-body imaging (CT or PET/CT) every 6–12 months for the first 2–3 years, given the higher recurrence rate (44%) that approaches stage III disease 2, 4.
• Imaging should be symptom-directed for stage IIB patients, reserving cross-sectional studies for clinical findings suggestive of recurrence 2.

Stage III (IIIA–IIID) Melanoma

• Clinical examination every 3–4 months for years 1–2, every 4–6 months for year 3, then every 6–12 months through year 5 3, 4.
• Routine cross-sectional imaging (whole-body CT with contrast or PET/CT, plus brain MRI) every 6 months for the first 2–3 years, then annually is recommended because 50% of recurrences in stage IIC–IIIC patients are detected by imaging in asymptomatic individuals 2.
• Lymph node ultrasound can supplement physical examination, particularly in the nodal basin at risk, as it detected 21% of recurrences in prospective surveillance studies and many were classified as early detection 3.
• The median time to recurrence in stage III disease is approximately 2.6 years overall, but varies significantly by substage: stage IIIA has lower risk, whereas stage IIIB–IIIC patients experience recurrence rates of 40–44% 4.

Rationale for Intensive Surveillance in Stage III

• Early detection of recurrence enables salvage therapy: in stage IIC–IIIC cohorts, 57% of patients with detected recurrence underwent surgical resection, and 39% received targeted therapy or immune checkpoint inhibitors 2.
• Pathological response to neoadjuvant therapy predicts recurrence timing: patients with ≤10% viable tumor after neoadjuvant pembrolizumab had a median time to recurrence of 3.9 years versus 0.6 years for those with >10% viable tumor, underscoring the need for extended surveillance beyond 2–3 years in responders 5.
• Patients achieving a complete pathological response (pCR) or major pathological response (MPR) after neoadjuvant pembrolizumab had 100% 5-year overall survival and late recurrences (median 3.9 years), justifying prolonged follow-up even in excellent responders 5.

Imaging Modalities

• Whole-body CT with contrast (chest/abdomen/pelvis) or PET/CT are the preferred modalities for stage III surveillance 2.
• Brain MRI should be included in routine imaging for stage III patients, as CNS metastases are a common site of first recurrence 2.
• Chest X-ray alone is insufficient for stage IIC–III disease, as it misses extrathoracic and nodal recurrences 2.

Detection Patterns and Implications

• In stage I–III disease, physical examination detected 50% of all recurrences, emphasizing the critical role of thorough skin and nodal basin examination 3.
• Asymptomatic detection by imaging occurred in 50% of stage IIC–IIIC recurrences, and these patients had access to curative-intent surgery or systemic therapy 2.
• Second primary melanomas are detected in approximately 3% of patients during surveillance (62 second primaries in 2,008 patients over 2 years), reinforcing the need for full-body skin examination at every visit 3.

Duration of Surveillance

• Intensive surveillance (every 3–6 months with imaging) should continue for at least 3 years, as the majority of recurrences occur within this window 4, 5.
• Extended follow-up beyond 5 years is warranted for patients who achieved pCR or MPR, as late recurrences (up to 3.9 years median) remain salvageable with 100% 5-year survival in this subgroup 5.
• After year 5, annual visits with full-body skin examination are appropriate for all stages to detect second primary melanomas and very late recurrences 3, 4.

Common Pitfalls

• Underestimating stage IIC risk: these patients have recurrence rates (44%) comparable to stage IIIB–IIIC and warrant imaging surveillance similar to stage III 2, 4.
• Stopping surveillance too early in pCR patients: late recurrences occur in this favorable subgroup, and they remain highly salvageable if detected early 5.
• Relying solely on imaging without thorough physical examination: half of recurrences are detected clinically, and second primaries require visual inspection 2, 3.
• Applying cutaneous melanoma surveillance to uveal melanoma: uveal melanoma has distinct biology and metastatic patterns; do not extrapolate these recommendations to non-cutaneous subtypes 6.