RESUMEN
BACKGROUND: Advanced penile carcinoma is characterized by poor prognosis. Most data on prognostic factors are based on small study cohorts, and even meta-analyses are limited in patient numbers. Therefore, there is still a lack of evidence for clinical decisions. In addition, the most recent TNM classification is questionable; in line with previous studies, we found that it has not improved prognosis estimation. METHODS: We evaluated 297 patients from Germany, Russia, and Portugal. Tissue samples from 233 patients were re-analyzed by two experienced pathologists. HPV status, p16, and histopathological parameters were evaluated for all patients. RESULTS: Advanced lymph node metastases (N2, N3) were highly significantly associated with reductions in metastasis-free (MFS), cancer-specific (CS), and overall survival (OS) rates (p = <0.001), while lymphovascular invasion was a significant parameter for reduced CS and OS (p = 0.005; p = 0.007). Concerning the primary tumor stage, a significant difference in MFS was found only between pT1b and pT1a (p = 0.017), whereas CS and OS did not significantly differ between T categories. In patients without lymph node metastasis at the time of primary diagnosis, lymphovascular invasion was a significant prognostic parameter for lower MFS (p = 0.032). Histological subtypes differed in prognosis, with the worst outcome in basaloid carcinomas, but without statistical significance. HPV status was not associated with prognosis, either in the total cohort or in the usual type alone. CONCLUSION: Lymphatic involvement has the highest impact on prognosis in penile cancer, whereas HPV status alone is not suitable as a prognostic parameter. The pT1b stage, which includes grading, as well as lymphovascular and perineural invasion in the T stage, seems questionable; a revision of the TNM classification is therefore required.
RESUMEN
BACKGROUND: Penile cancer is a rare but often lethal tumour disease, especially in the metastatic stage. Most data on prognostic factors for penile cancer are based on small patient cohorts, and even meta-analyses are mostly limited in terms of patient numbers. There is a lack of sufficient parameters to predict the metastatic risk of these tumours. Furthermore, the role of the HPV status for the prognosis, and, in this regard, of p16INK4a is still unclear. MATERIAL AND METHODS: In this study, 236 patients from an international multicentre cohort were analysed with regard to histological subtypes, HPV and p16 status, and other clinical parameters. The HPV status was only graded as HPV-positive if HPV was detected by PCR and the p16 status defined by immunochemistry was positive. The statistical analysis was carried out using the Kaplan-Meier method as well as the log-rank test and a univariable and multivariable analysis using the Cox regression model. RESULTS: A positive HPV status was not a significant parameter for either metastasis-free (MFS), tumour-specific (CSS) or overall survival (OS). p16-positive tumours showed a significantly better MFS (p=0.026), which was also confirmed in the subgroup analysis of HPV-negative tumours (p=0.037) without differences in CSS or OS. In the usual type, there was also a trend towards an improved MFS, but without statistical significance (p=0.070). p16-positive tumours were associated with a highly significantly better MFS (hazard ratio 0.3; p=0.004) in the multivariable Cox regression, while patients with a pT1b tumour stage or advanced lymph node metastasis showed a significantly worse survival. In the multivariable analysis of HPV-negative tumours, p16 status was also confirmed as an independent predictor of MFS (Hazard ratio 0.2; p=0.007). CONCLUSION: HPV status alone seems to be lacking prognostic relevance. In contrast, p16 status was confirmed as an independent prognostic factor. Thus, the expression of p16INK4a is associated with a significantly better MFS. Especially in HPV-negative tumours, the p16 status should be evaluated with regard to the prognostic value and thus also with a view to the treatment decision.