F-18 Fluorodeoxyglucose Positron Emission Tomography with Computed Tomography Has High Diagnostic Value for Pelvic and Distant Staging in Patients with High-risk Penile Carcinoma

Abstract

BackgroundFor penile cancer patients with pelvic metastases, multimodal treatment is advised, but pelvic lymph node metastases are often found upon surgical resection only. Early selection for multimodal treatment requires reliable noninvasive staging. ObjectiveTo evaluate the diagnostic value of 18F-fluorodeoxyglucose positron emission tomography with computed tomography (FDG-PET/CT) for staging pelvic lymph nodes and distant metastases in high-risk penile cancer patients. Design, setting, and participantsFDG-PET/CT scans performed in patients with clinically overt inguinal lymph node metastases and/or high-risk primary tumors (bulky T3 or T4) were retrospectively analyzed. Outcome measurements and statistical analysisAll scans were reviewed by two independent nuclear medicine physicians staging the pelvic nodes and distant metastases. FDG-PET/CT findings were compared with histology after node dissection if available, or with positive imaging or follow-up of at least 1 yr. Results and limitationsBetween 2006 and 2016, 61 patients met the inclusion criteria. For staging of pelvic nodes, sensitivity was 85% (specificity 75%, negative predictive value [NPV] 90%, and positive predictive value [PPV] 65%). For the detection of distant metastases, FDG-PET/CT had a PPV of 93%. Results are limited by the retrospective design and the lack of direct comparison with CT scanning alone. ConclusionsFDG-PET/CT has high sensitivity and a high NPV for staging of pelvic lymph nodes in high-risk penile cancer. It also has a high PPV for the detection of distant metastases, which were found in 23% of patients. Therefore, FDG-PET/CT enables early selection for multimodal treatment of patients with pelvic metastases and may help avoid futile treatment of patients with distant metastases. Patient summaryWe studied whether positron emission tomography with computed tomography (PET/CT) scans in patients with advanced penile cancer can detect metastases before lymph node surgery is done. PET/CT scans can detect or rule out pelvic lymph node metastases, and can detect distant metastases. This helps in making timely treatment decisions (before surgery).