FDG PET scans as evaluation of clinical response to dendritic cell vaccination in patients with malignant melanoma.
BACKGROUND
Measurements of tumour metabolism by [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) have been successfully applied to monitor tumour response after chemo- and chemo-radiotherapy and may not have the same limitations as other morphological imaging techniques. In this study it is investigated whether FDG-PET might add information on the efficacy of immune therapy.


METHODS
In a retrospective analysis data from patients with advanced progressive melanoma, treated with DC vaccinations and evaluated by PET/CT scans at baseline as well as after 6 vaccinations were analysed. If a patient achieved stable disease according to RECIST, additional vaccinations were given. The PET scans were evaluated according to EORTC guidelines.


RESULTS
PET/CT scans from 13 patients were evaluated. According to RECIST 3 patients achieved stable disease and 10 patients progressed. Interestingly, when evaluated by PET scans 2 patients had partial metabolic response and 1 patient had complete metabolic response of the 2 index lesions even though a new lesion appeared simultaneously. Ten patients were seen to have stable or progressive metabolic disease.


CONCLUSIONS
By adding PET scans to the CT evaluation of patients treated with DC vaccines, a more detailed picture of the single lesions was found. This seems to improve the clinical evaluation of the treatment. The lack of correlation between the PET and CT scans suggests that some of the increases in target lesions seen in CT scans might be due to oedema or immune-infiltrates and not progression of the disease. Thus, further investigation into the contribution of PET scans to the evaluation of cancer immunotherapy is needed.
Department of Haematology, Center for Cancer ImmuneTherapy (CCIT), University Hospital Herlev, Herlev, Denmark. Lotte.Engell-Noerregaard@regionh.dk
Lotte
L
Engell-Noerregaard
Helle W
HW
Hendel
Helle H
HH
Johannesen
Louise
L
Alslev
Inge Marie
IM
Svane
D000328:Adult; D000368:Aged; D019496:Cancer Vaccines / Q000627:therapeutic use*; D003713:Dendritic Cells / Q000276:immunology* / Q000637:transplantation; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008545:Melanoma / Q000000981:diagnostic imaging* / Q000276:immunology / Q000473:pathology / Q000628:therapy*; D008875:Middle Aged; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
D019496:Cancer Vaccines; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18