Recurrence of Melanoma After Initial Treatment: Diagnostic Performance of FDG PET in Posttreatment Surveillance

Abstract

Purpose In malignant melanoma, recurrence is often observed in distant areas from the primary site. While FDG PET is a sensitive imaging for detecting malignant lesions, the role of FDG PET in posttreatment surveillance period has not been investigated sufficiently. The aim of this study was to evaluate the value of PET during posttreatment surveillance in melanoma. Methods A total of 76 melanoma patients who underwent FDG PET during surveillance period after completion of the first treatment were retrospectively enrolled. PET scans were grouped according to the purpose and clinical situations, routine surveillance, or evaluating clinical suspicion. Final diagnosis of recurrence was determined by complete clinical evaluation or long-term follow-up. In each situation, the diagnostic role of FDG PET was assessed. Results A total of 143 scans of 76 patients were analyzed: 51 for clinical suspicion and 92 for routine surveillance. In the clinical suspicion group, PET correctly diagnosed non-recurrence in 10 cases (20%). In routine surveillance group, 16 cases (17%) presented recurrence, all of which was correctly diagnosed on PET. NPVand PPV were 100% and 76%, respectively. In subgroup analysis, sensitivity and NPV were higher in the low-risk group (stages I-II A) than in the high-risk group (stages II B-IV), while specificity and PPV were higher in the high-risk group. Conclusion In conclusion, FDG PET is an effective diagnostic tool in posttreatment surveillance of melanoma. Even in cases without clinical suspicion, melanoma recurs in a considerable proportion of patients, which can be sensitively diagnosed on PET.

Early Reassessment of Total Metabolic Tumor Volume on FDG-PET/CT in Advanced Melanoma Patients Treated with Pembrolizumab Predicts Long-Term Outcome

“…The role of volumetric parameters in FDG-PET/CT as a predictive biomarker has been demonstrated in different types of cancers [5,[13][14][15][16][17]. The total metabolic tumor volume is a valuable parameter as it reflects the extent and activity of the tumor [18][19][20].…”

“…Malignant melanoma is a frequently occurring type of cancer and the incidence is increasing faster than that of other malignancies [1][2][3]. Immune checkpoint inhibitors (ICI's) have been shown to be more effective in the treatment of advanced melanoma than conventional chemotherapy due to the high immunogenicity of the tumor [4][5][6][7]. Pembrolizumab is an example of an ICI in which the anti-tumoral immune response is triggered by blocking the interaction of programmed cell death 1 (PD-1) with its ligands PDL-1 and PDL-2.…”

Usefulness of 68Ga-DOTATOC PET/CT to localize the culprit tumor inducing osteomalacia

“…The evaluation of treatment response or detection of the recurred/remnant tumor using post-treatment 18 F-FDG PET/CT is a popular approach in the field of oncology 32 . To the best of our knowledge, we have shown, for the first time, the additional value of follow-up with 68 Ga-DOTATOC PET/CT after the basal scan to detect residual tumors whose hypophosphatemia persists even after surgery.…”

18F‐FDG positron emission tomography–computed tomography has a low positive predictive value for detecting occult recurrence in asymptomatic patients with high‐risk Stages IIB, IIC, and IIIA melanoma

“…3 Previous studies have shown that 18 F-FDG-PET/CT has a high negative predictive value (NPV) of 80%-98%; however, a wider range of uncertainty surrounds its positive predictive value (PPV) of approximately 56%-86%, due to significant heterogeneity between prior study designs and stages included. [21][22][23][24][25][26] In other words, while negative results tend to accurately report the absence of recurrence, errors more often arise in interpreting the clinical course of action for positive results that may not represent true recurrence. To address this gap in the literature, the goal of this study is to determine the utility of 18 F-FDG PET/CT for detecting asymptomatic recurrence of high-risk Stages II and IIIA melanoma after primary surgical treatment.…”

“…Five-year MSS was 93% (95% CI: 80%-99%) for Stage IIB, 86% (95% CI: 74%-95%) for Stage IIC, and 94% (95% CI: 82%-99%) for Stage IIIA. The p-value of the Gray test for equality of cumulative incidence functions was 0.315 stages and clinical indications for imaging [21][22][23][24][25][26]. For example, the paper by Lewin et al25 reported in subgroup analysis an NPV of 84%for Stage IIIA at 18 months, but an overall PPV of 56% of any scan for relapse.…”