Prognostic factors in Taiwanese patients with penile-invasive squamous cell carcinoma

A modified clinicopathological tumor staging system for survival prediction of patients with penile cancer

BACKGROUND

The 8th American Joint Committee on Cancer tumor-node-metastasis (AJCC-TNM) staging system is based on a few retrospective single-center studies. We aimed to test the prognostic validity of the staging system and to determine whether a modified clinicopathological tumor staging system that includes lymphovascular embolization could increase the accuracy of prognostic prediction for patients with stage T2-3 penile cancer.

METHODS

A training cohort of 411 patients who were treated at 2 centers in China and Brazil between 2000 and 2015 were staged according to the 8th AJCC-TNM staging system. The internal validation was analyzed by bootstrap-corrected C-indexes (resampled 1000 times). Data from 436 patients who were treated at 15 centers over four continents were used for external validation.

RESULTS

A survivorship overlap was observed between T2 and T3 patients (P = 0.587) classified according to the 8th AJCC-TNM staging system. Lymphovascular embolization was a significant prognostic factor for metastasis and survival (all P < 0.001). Based on the multivariate analysis, only lymphovascular embolization showed a significant influence on cancer-specific survival (CSS) (hazard ratio = 1.587, 95% confidence interval = 1.253-2.011; P = 0.001). T2 and T3 patients with lymphovascular embolization showed significantly shorter CSS than did those without lymphovascular embolization (P < 0.001). Therefore, a modified clinicopathological staging system was proposed, with the T2 and T3 categories of the 8th AJCC-TNM staging system being subdivided into two new categories as follows: t2 tumors invade the corpus spongiosum and/or corpora cavernosa and/or urethra without lymphovascular invasion, and t3 tumors invade the corpus spongiosum and/or corpora cavernosa and/or urethra with lymphovascular invasion. The modified staging system involving lymphovascular embolization showed improved prognostic stratification with significant differences in CSS among all categories (all P < 0.005) and exhibited higher accuracy in predicting patient prognoses than did the 8th AJCC-TNM staging system (C-index, 0.739 vs. 0.696). These results were confirmed in the external validation cohort.

CONCLUSIONS

T2-3 penile cancers are heterogeneous, and a modified clinicopathological staging system that incorporates lymphovascular embolization may better predict the prognosis of patients with penile cancer than does the 8th AJCC-TNM staging system. Trial registration This study was retrospectively registered on Chinese Clinical Trail Registry: ChiCTR16008041 (2016-03-02). http://www.chictr.org.cn.

The role of perineural invasion in penile cancer: a meta-analysis and systematic review

The significance of perineural invasion (PNI) present in penile cancer (PC) is controversial. In order to clarify the predictive role of PNI in the inguinal lymph node (ILN) metastases (ILNM) and oncologic outcome of patients, we performed this meta-analysis and systematic review. The search of PubMed, Embase, and Web of Science was conducted for appropriate studies, up to 20 January 2018. The pooled odds ratio (OR) and hazard ratio (HR) with their 95% confidence interval (CI) were applied to evaluate the difference in ILNM and oncologic outcome between patients present with PNI and those who were absent. A total of 298 in 1001 patients present with PNI were identified in current meta-analysis and systematic review. Significant difference was observed in ILNM between PNI present and absent from patients with PC (OR = 2.98, 95% CI = 2.00-4.45). Patients present with PNI had a worse cancer-specific survival (CSS) (HR = 3.58, 95% CI = 1.70-7.55) and a higher cancer-specific mortality (CSM) (HR = 2.20, 95% CI = 1.06-3.82) than those cases without PNI. This meta-analysis and systematic review demonstrated the predictive role of PNI in ILNM, CSS, and CSM for PC patients.