Detection of metastatic disease in penile cancer patients with 18F-FDG PET/CT
Jill C. Buckley, MD, Leonard Zinman, MD.
Lahey Clinic, Burlington, MA, USA.
Objective: To evaluate FDG PET/CT for the detection of metastatic penile cancer.
Methods: 10 patients (age 47 to 81) with a diagnosis of squamous cell cancer of the penis underwent FDG PET/CT from 1/2007 to 1/2009 were evaluated. 21 PET/CT were performed, 5 for initial staging and 16 for restaging. All scans were done on a GE PET/CT (DVCT) after injection of approximately 15 mCi of 18F -FDG. Noncontrast CT was performed for attenuation correction and anatomic correlation. All PET/CT positive lesions were correlated with pathology. Negative scans were followed by serial PET/CT, other imaging or clinical evaluation. PET/CT findings were compared to pathology in 4 patients.
Results: Five patients were scanned before primary tumor resection. All primary lesions were identified readily identified by PET. 3 patients were PET/CT positive for inguinal node metastases on initial staging. 2 of those patients had persistent positive PET/CT scans after primary tumor resection and underwent inguinal lymph node dissection confirming the finding with pathology. One patient who had an initially negative PET/CT developed abnormal uptake in an enlarged lymph node after 7 months, which was also confirmed metastasis. Another restaging study demonstrated abnormalities in inguinal, pelvis and lung that had confirmed metastasis in the inguinal area. PET/CT correctly identified benign lesions in 3 patients which include a lung nodule, an 18 mm inguinal node and a palpable inguinal node. The sensitivity of detecting metastasis is 100%. The specific is 83.3%. PPV is 80% and NPV is 100%. Based on PET/CT findings, 3/11 patients had altered clinical management.
18F-FDG PET /CT appears to be accurate in detecting regional lymph node and distant metastasis in penile cancer patients. Additional experience is needed to confirm PET/CT as a useful diagnostic exam in the clinical management of invasive penile cancer.