Journal Article

The diagnostic accuracy and clinical impact of FDG-PET/CT follow-up for patients on adjuvant immunotherapy for high-risk malignant melanoma

Grupe, Peter, Spatzek, Anders D., Gerke, Oke, Andersen, Jesper A. S., Hildebrandt, Malene G., Hess, Søren, Holdgaard, Paw C., Bastholt, Lars, Vilstrup, Mie H.

2022

Overview

Objective The benefit of FDG-PET/CT in follow-up of patients treated with adjuvant immunotherapy after resection of high-risk malignant melanoma (MM) is debated. This study evaluated the diagnostic accuracy and clinical impact of FDG-PET/CT for diagnosing MM recurrence during the first year after surgery. Methods We retrospectively included 124 patients with resected high-risk MM, who received adjuvant immunotherapy and follow-up FDG-PET/CT. Clinical information and AJCC-8 stage was obtained from patients’ medical records. Recurrence was verified by biopsy/progression on a subsequent scan leading to change of treatment. Non-recurrence was assumed when no metastases were observed until the subsequent follow-up scan. Incidence of recurrence, sensitivity, specificity, positive and negative predictive values (PPV and NPV) were outcome measures. Results Incidence rate of MM recurrence was 0.27 [95% CI 0.17–0.37] per person-year during the first-year. Recurrence was detected in 13 patients (10%) at 3-month FDG-PET/CT, in 10 patients (8.1%) at 6 months, 1 patient (0.8%) at 9 months, 3 patients (2.4%) at 12 months. The overall sensitivity, specificity, PPV, and NPV were 97% [86–99], 82% [78–86], 39% [29–50], and 99% [98–99], respectively. The PPV trended towards higher values as disease stage increased. At the 3-month scan, the majority of actions derived from positive findings were surgery or earlier expedition of the subsequent follow-up scan. Conclusion The high rate of recurrence in patients with high-risk MM treated with adjuvant immunotherapy emphasizes the need for follow-up. The potential harm by a moderately low specificity reflecting a high number of false-positive results must be weighed against the benefit of early detection of recurrence.

• Publisher: Springer Berlin Heidelberg,Springer Nature B.V
• Subject: Biopsy / Cardiology / Cohort analysis / Computed tomography / Diagnostic systems / Fluorodeoxyglucose F18 / Follow-Up Studies / Humans / Imaging / Immunotherapy / Medical diagnosis / Medical records / Medicine / Medicine & Public Health / Melanoma / Melanoma - diagnostic imaging / Melanoma - pathology / Melanoma - therapy / Melanoma, Cutaneous Malignant / Metastases / Neoplasm Recurrence, Local - diagnostic imaging / Nuclear Medicine / Oncology / Oncology – General / Original Article / Orthopedics / Patients / Positron emission / Positron emission tomography / Positron Emission Tomography Computed Tomography - methods / Radiology / Radiopharmaceuticals / Retrospective Studies / Risk / Sensitivity / Sensitivity and Specificity / Skin cancer / Skin Neoplasms / Surgery / Tomography