Contemporary outcomes from the use of regular imaging to detect relapse in high-risk cutaneous melanoma

Abstract

BackgroundAgreement on the utility of imaging follow-up in patients with high-risk melanoma is lacking. A UK consensus statement recommends a surveillance schedule of CT or positron-emission tomography-CT and MRI brain (every 6 months for 3 years, then annually in years 4 and 5) as well as clinical examination for high-risk resected Stages II and III cutaneous melanoma. Our aim was to assess patterns of relapse and whether imaging surveillance could be of clinical benefit.Patients and methodsA retrospective study of patients enrolled between July 2013 and June 2015 from three UK tertiary cancer centres followed-up according to this protocol was undertaken. We evaluated time-to-recurrence (TTR), recurrence-free survival (RFS), method of detection and characteristics of recurrence, treatment received and overall survival (OS).ResultsA total of 173 patients were included. Most (79%) had treated Stages IIIB and IIIC disease. With a median follow-up of 23.3 months, 82 patients (47%) had relapsed. Median TTR was 10.1 months and median RFS was 21.2 months. The majority of recurrences (66%) were asymptomatic and detected by scheduled surveillance scan. Fifty-six (68%) patients recurred with Stage IV disease, with a median OS of 25.3 months; 26 (31.7%) patients had a locoregional recurrence, median OS not reached (P=0.016). Patients who underwent surgery at recurrence for either Stage III (27%) or IV (18%) disease did not reach their median OS. The median OS for the 33 patients (40%) who received systemic therapy was 12.9 months.ConclusionImaging appears to reliably detect subclinical disease and identify patients suitable for surgery, conferring favourable outcomes. The short median TTR provides rationale to intensify imaging schedule in the first year of surveillance. The poor OS of patients treated with systemic therapy probably reflects the relatively inferior treatment options during this time and requires further evaluation in the current era.

Follow‐up of the melanoma patient

“…Regarding timing, over half of relapses occur within 1 year of diagnosis, and the significant majority occur within 3 years (Table ) . Risk of recurrence for all melanoma patients approaches zero, but relapses after 10 years are well documented.…”

“…A main focus of discussion is whether surveillance CT will actually detect recurrences in a meaningful proportion of asymptomatic patients before those patients might prompt work‐up and detection by their provider. The detection of recurrences by surveillance CT scans has been reported to be between 24% and 59% when reviewing late stage II and stage III disease . Several more recent studies found that CT scans first detect at least half of systemic recurrences .…”

“…However, given that the negative predictive value of a CT scan approaches 100%, patients may also be reassured after a negative scan . Although routine surveillance scans may present inconvenience to the patient, success with a high rate of compliance has been reported . Radiation exposure will always be a risk of additional CT imaging.…”

“…There are few data on PET/CT in melanoma surveillance, and a wide range of opinions regarding utility have been published. Three recent retrospective reports, each with between 170 and 370 stage II or III patients, found an imaging surveillance regimen involving PET/CT detected 50% to 69% of recurrences, with median follow‐up ranging approximately 2 to 4 years . In another, a single PET/CT at a median of 7 months detected 24% of all recurrences .…”

“…There are very few published data on brain MRI for melanoma surveillance. Brain metastasis is identified by MRI as the initial site of relapse in approximately 7% to 13% of recurrences in stage III and high‐risk stage II patients . More advanced substages (especially IIIC) have a higher risk of initial relapse in the brain, although it is still low .…”