Prediction of positron emission tomography/computed tomography (PET/CT) positivity in patients with high-risk primary melanoma

• Published in: American journal of nuclear medicine and molecular imaging 2016-01, Vol.6 (5), p.277-285
• Main Authors: Danielsen, Maria, Kjaer, Andreas, Wu, Max, Martineau, Lea, Nosrati, Mehdi, Leong, Stanley Pl, Sagebiel, Richard W, Miller, III, James R, Kashani-Sabet, Mohammed
• Format: Article
• Language: English
• Subjects: Original
• ISSN: 2160-8407; 2160-8407

Positron emission tomography/computed tomography (PET/CT) is an important tool to identify occult melanoma metastasis. To date, it is controversial which patients with primary cutaneous melanoma should have staging PET/CT. In this retrospective analysis of more than 800 consecutive patients with cutaneous melanoma, we sought to identify factors predictive of PET/CT positivity in the setting of newly-diagnosed high-risk primary melanoma to determine those patients most appropriate to undergo a PET/CT scan as part of their diagnostic work up. 167 patients with newly-diagnosed high-risk primary cutaneous melanoma underwent a PET/CT scan performed as part of their initial staging. Clinical and histologic factors were evaluated as possible predictors of melanoma metastasis identified on PET/CT scanning using both univariate and multivariate logistic regression. In all, 32 patients (19.2%) had a positive PET/CT finding of metastatic melanoma. In more than half of these patients (56.3%), PET/CT scanning identified disease that was not detectable on clinical examination. Mitotic rate, tumor thickness, lymphadenopathy, and bleeding were significantly predictive of PET/CT positivity. A combinatorial index constructed from these factors revealed a significant association between number of high-risk factors observed and prevalence of PET/CT positivity, which increased from 5.8% (with the presence of 0-2 factors) to 100.0%, when all four factors were present. These results indicate that combining clinical and histologic prognostic factors enables the identification of patients with a higher likelihood of a positive PET/CT scan.