Corpora Cavernos invasion vs. Corpus Spongiosum invasion in Penile Cancer: A systematic review and meta-analysis

Objective: Changes were made in the 8^th edition of the American Joint Committee on Cancer (AJCC) staging system according to cavernosum invasion for penile squamous cell carcinoma. This study aimed to determine the difference of prognostic validity between corpora cavernosa (CC) invasion and corpus spongiosum (CS) invasion. Methods: In this study, we searched PubMed, Cochrane CENTRAL, and Embase to select English-language articles until July 15, 2020. Pooled analyses of hazard ratios (HRs) and odds ratios (ORs) were performed. Results: Eleven studies including 3692 cases were included in the final ananlysis (1431 cases with CC and 1360 cases with CS). According to the anatomical structure, the pooled results demonstrated that patients with CC invasion had a similar rate of LNM to those with CS invasion (OR 1.34, 95% confidence interval (CI) 0.97-1.86; P=0.076). However, patients with CC invasion had a higher rate of lymph node metastasis (LNM) than those with CS invasion according to the 8^th edition tumor stage (OR 1.58, 95% CI 1.14-2.21; P<0.001). Regarding survival, patients with CS invasion obtained a significantly better cancer-specific survival (CSS) (HR, 0.67; 95% CI, 0.46-0.96; P=0.030), but not in overall survival (OS) (HR: 1.30; 95% CI, 0.52-3.20; P=0.585) than those with CC invasion. No a significant publication bias was observed by Begg's and Egger's tests. Conclusions: The systematic comparison suggests that patients with CS invasion had better CSS than those with CC invasion. CC invasion was associated with a high risk of LNM. The conclusions should be validated by large-scale studies.