title: Association between the use of surveillance PET/CT and the detection of potentially salvageable occult recurrences among patients with resected high-risk melanoma.
abstract: The optimal surveillance for patients with resected high-risk melanoma is controversial. Select locoregional or oligometastatic recurrences can be cured with salvage resection. Data on the ability of PET/CT to detect such recurrences are sparse. We evaluated whether surveillance PET/CT in patients with resected stage III-IV melanoma led to detection of clinically occult recurrences amenable to curative-intent salvage treatment. We retrospectively identified 1429 melanoma patients who underwent PET/CT between January 2008 and October 2012 at Mayo Clinic (Rochester, Minnesota). A total of 1130 were excluded because of stage I-II, ocular or mucosal melanoma, incomplete resection, PET/CT not performed for surveillance or performed at a different institution, and records not available. A total of 299 patients were eligible. Overall, 162 (52%) patients developed recurrence [locoregional: 77 (48%), distant: 85 (52%)]. The first recurrence was clinically occult in 98 (60%) and clinically evident in 64 (40%). Clinically evident recurrences were more often superficial (skin, subcutaneous, or nodal) or in the brain, whereas clinically occult recurrences more often visceral. Overall, 90% of all recurrences were detected by 2.8 years. In all, 70% of patients with recurrence underwent curative-intent salvage treatment (locoregional: 94%, distant: 48%), with similar rates for clinically occult versus clinically evident recurrences (66 vs. 75%, P=0.240). Overall survival was superior among those who underwent curative-intent salvage treatment [5.9 vs. 1.2 years; hazard ratio=4.27, 95% confidence interval (CI)=2.68-6.80; P<0.001], despite 79% developing recurrence again. PET/CT had high sensitivity (88%, 95% CI=79.94-93.31%), specificity (90%, 95% CI=88.56-91.56%), and negative predictive value (99%, 95% CI=98.46-99.52%). However, the positive predictive value was only 37% (95% CI=31.32-43.68%). In patients with resected stage III-IV melanoma, surveillance PET/CT detected a large proportion of clinically occult recurrences amenable to curative-intent salvage treatment. Despite a high rate of second relapse, curative-intent salvage treatment was associated with superior overall survival. Even though PET/CT had high sensitivity, specificity, and negative predictive value, positive predictive value was poor, highlighting the need for histologic confirmation of PET/CT-detected abnormalities.
authors.affiliation: Departments of aOncology bRadiology cDepartment of Biomedical Statistics & Informatics, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Roberto A
authors.initials: RA
authors.lastname: Leon-Ferre
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Kottschade
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Block
authors.forename: Robert R
authors.initials: RR
authors.lastname: McWilliams
authors.forename: Roxana S
authors.initials: RS
authors.lastname: Dronca
authors.forename: Edward T
authors.initials: ET
authors.lastname: Creagan
authors.forename: Jacob B
authors.initials: JB
authors.lastname: Allred
authors.forename: Val J
authors.initials: VJ
authors.lastname: Lowe
authors.forename: Svetomir N
authors.initials: SN
authors.lastname: Markovic
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D008545:Melanoma / Q000473:pathology; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000473:pathology; D000072078:Positron Emission Tomography Computed Tomography / Q000379:methods*; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000473:pathology