Metastatic involvement of the inguinal lymph nodes is associated with decreased survival and is a strong prognostic factor in penile squamous cell carcinoma. The aim of the current systematic review was to evaluate the accuracy of (18)F-FDG PET/CT for inguinal lymph node staging in penile squamous cell carcinoma and possible influential factors.

Medline, SCOPUS, Springer, Science Direct, and Google Scholar were searched using the key words "(penile or penis) and PET," with no date or language limitation. The meeting abstracts were not excluded either. Statistical pooling was performed using the random-effects model.

Seven studies were included in the meta-analysis. One article had 2 different subgroups of patients, and each subgroup was considered as a separate study. Pooled sensitivity and specificity were 80.9% (95% confidence interval [CI]: 69.5%-89.4%) and 92.4% (95% CI: 86.8%-96.2%), respectively. Pooled sensitivity was 96.4% (95% CI: 81.7%-99.9%) for cN+ and 56.5% (95% CI: 34.5%-76.8%) for cN0 patients.

(18)F-FDG PET/CT imaging has relatively low sensitivity (especially in cN0 patients) for detection of inguinal lymph node involvement in penile cancer patients, which does not justify its routine use. However, patients with clinically palpable lymph nodes may benefit from (18)F-FDG PET/CT because the sensitivity in this subgroup of patients is high.