A Modified Histopathologic Staging in Penile Squamous Cell Carcinoma Predicts Nodal Metastasis and Outcome Better Than the Current AJCC Staging

Factors predictive of recurrence, metastasis and death in node-negative penile squamous cell carcinoma: A retrospective multicentre cohort study

BACKGROUND

Penile squamous cell carcinoma (PSCC) carries significant morbidity and mortality. Literature is limited regarding prognostic factors, especially prognostic factors for development of metastasis.

OBJECTIVES

To identify independent prognostic factors associated with poor outcomes, defined as local recurrence (LR), metastasis and disease-specific death (DSD) in clinically node-negative PSCC undergoing local therapy.

METHODS

Thirty-two-year Retrospective Multicenter Cohort Study of 265 patients with histologically diagnosed PSCC at three tertiary care centres. Predictive models based on patient or tumour characteristics were developed.

RESULTS

Local recurrence occurred in 56 patients, metastasis in 52 patients and DSD in 40 patients. In multivariable models, the following five factors were independent prognostic factors based on subhazard ratio (SHR): history of balanitis (LR SHR: 2.3; 95% CI 1.2-4.2), poor differentiation (metastasis SHR 1.9; 95% CI 1.0-3.6), invasion into the corpora (metastasis SHR: 3.0; 95% CI 1.5-5.8 and DSD SHR: 4.5; 95% CI 1.7-12.1), perineural invasion (PNI) (metastasis SHR: 2.8; 95% CI 1.4-5.5 and DSD SHR: 3.5; 95% CI, 1.6-7.8) and a history of phimosis (DSD SHR: 2.5; 95% CI 1.2-5.3). The 5-year cumulative incidence of metastasis was higher for tumours with PNI [cumulative incidence function (CIF) = 55%, 95% CI 38-75 vs. CIF 15%, 95% CI 11-22], corporal invasion (CIF: 35%, 95% CI 26-47 vs. 12%, 95% CI 7-19) and poorly differentiated tumours (CIF = 46%, 95% CI 31-64 vs. CIF 15%, 95% CI 11-22).

CONCLUSIONS

History of balanitis, history of phimosis, PNI, corporal invasion and poor differentiation are independent risk factors associated with poor outcomes. Since poor differentiation and PNI currently constitute only T1b disease, prognostic staging can likely be improved.

Comparison of a modified staging system with 8th edition AJCC criteria in a North American cohort of pT2/pT3 HPV-negative penile squamous cell carcinoma

The staging for pT2/pT3 penile squamous cell carcinoma (pSCC) has undergone major changes. Some authors proposed criteria wherein the distinction between pT2/pT3 was made using the same histopathological variables that are currently utilized to differentiate pT1a/pT1b. In this single-institution, North American study, we focused on (HPV-negative) pT2/3 pSCCs (i.e., tumors invading corpus spongiosum/corpus cavernosum), and compared the prognostic ability of the following systems: (i) AJCC (8th edition) criteria; (ii) modified staging criteria proposed by Sali et al. (Am J Surg Pathol. 2020; 44:1112-7). In the proposed system, pT2 tumors were defined as those devoid of lymphovascular invasion (LVI) or perineural invasion (PNI), and were not poorly differentiated; whereas pT3 showed one or more of the following: LVI, PNI, and/or grade 3. 48 pT2/pT3 cases were included (AJCC, pT2: 27 and pT3: 21; Proposed, pT2: 22 and pT3: 26). The disease-free survival (DFS) and progression-free survival (PFS) did not differ between pT2 and pT3, following the current AJCC definitions (p = 0.19 and p = 0.10, respectively). When the pT2/3 stages were reconstructed using the modified criteria, however, a statistically significant difference was present in both DFS and PFS between pT2 and pT3 (p = 0.004 and p = 0.003, respectively). The proposed staging system has the potential to improve the prognostication of pT2/pT3 tumors in pSCC. Each of these histopathologic variables has been shown to have a significant association with outcomes in pSCC, which is an advantage. Further studies are needed to demonstrate the utility of this modified staging system in patient populations from other geographic regions.

Multiparametric Magnetic Resonance Imaging of Penile Cancer: A Pictorial Review

The role of multiparametric magnetic resonance imaging (mpMRI) in assessing penile cancer is not well defined. However, this modality may be successfully applied for preoperative staging and patient selection; postoperative local and regional surveillance; and assessments of treatment response after oncological therapies. Previous studies have been mostly limited to a few small series evaluating the accuracy of MRI for the preoperative staging of penile cancer. This review discusses the principles of non-erectile mpMRI, including functional techniques and their applications in evaluating the male genital region, along with clinical protocols and technical considerations. The latest clinical classifications and guidelines are reviewed, focusing on imaging recommendations and discussing potential gaps and disadvantages. The development of functional MRI techniques and the extraction of quantitative parameters from these sequences enables the noninvasive assessment of phenotypic and genotypic tumor characteristics. The applications of advanced techniques in penile MRI are yet to be defined. There is a need for prospective trials and feasible multicenter trials due to the rarity of the disease, highlighting the importance of minimum technical requirements for MRI protocols, particularly image resolution, and finally determining the role of mpMRI in the assessment of penile cancer.

RAB20 Promotes Proliferation via G2/M Phase through the Chk1/cdc25c/cdc2-cyclinB1 Pathway in Penile Squamous Cell Carcinoma

RAB20, a member of the RAS GTPase oncogene family, is overexpressed in several cancers with poor outcomes, promoting tumorigenesis and inducing genomic instability. Here, we performed comprehensive genomic sequencing on eight penile squamous cell carcinoma (PSCC) and normal tissue pairs and found that RAB20 was upregulated in tumors, especially in metastatic lymph nodes. RAB20 overexpression in tumors was further verified by qPCR, Western blotting, and immunohistochemistry of our newly established PSCC cell lines and paired tissues. The clinical significance of RAB20 was validated in 259 PSCC patients, the largest cohort to date, and high RAB20 expression positively correlated with the T, N, M status, extranodal extension, and clinical stage (all p < 0.01). RAB20 was an unfavorable independent prognostic indicator in the survival analysis (p = 0.011, HR = 2.090; 95% Cl: 1.183−4.692), and PSCC patients with high RAB20 expression experienced shorter 5-year cancer-specific survival times (p < 0.001). Furthermore, tumorigenesis assays demonstrated that RAB20 knockdown inhibited cell proliferation, migration, and colony formation in vitro and tumor growth in vivo. RAB20 depletion also induced PSCC cell cycle arrest at G2/M by increasing Chk1 expression and promoting cdc25c phosphorylation to reduce cdc2-cyclinB1 complex formation. Our study revealed an oncogenic role for RAB20 in promoting PSCC cell proliferation at the G2/M phase via the Chk1/cdc25c/cdc2-cyclinB1 pathway. Thus, RAB20 could be a promising prognostic biomarker of advanced PSCC with poor patient survival outcomes and could be a potential therapeutic target.

A comparative study of AJCC and the modified staging system in pT2/pT3 penile squamous cell carcinoma- A validation on an external dataset

AIMS

The recent changes in the American Joint Commission on Cancer-8^th edition (AJCC-8E) pT2 and pT3 tumor definitions for penile cancer need robust validation studies. A recent study redefined and modified the pT2 and pT3 stages incorporating the histopathological variables (tumor grade, lymphovascular invasion, perineural invasion) similar to that used in the current AJCC-8E pT1 stage tumor subclassification. In this study, we validate and compare this proposed staging with the AJCC staging systems, on an external dataset.

METHODS AND RESULTS

The dataset from a previously published study was obtained. pT2 and pT3 stages were reconstructed as per AJCC 7^th edition (AJCC-7E), AJCC-8E, and the proposed staging. The staging systems were correlated with nodal metastasis, disease-free survival (DFS), cancer-specific survival (CSS), and overall survival (OS). All systems were compared using receiver operating characteristics (ROC) curves. A total of 281 cases formed the study cohort. AJCC-8E (p=0.031) and the proposed staging (p=0.003) correlated with nodal metastasis on adjusted analysis, the latter with a better strength of association (AJCC-8E, γ= -.471, proposed, γ= -.625). On adjusted analysis, all the staging systems had a significant correlation with DFS, while only AJCC-8E and the proposed staging correlated with CSS and OS. On ROC curve analysis, the proposed staging had the highest area under the curve and was the only staging system to statistically correlate with all the outcome variables.

CONCLUSIONS

The proposed staging for pT2/pT3 tumor stages in penile cancer may improve the prognostic and predictive ability.

The peri- and intratumoral immune cell infiltrate and PD-L1 status in invasive squamous cell carcinomas of the penis

INTRODUCTION

Penile carcinomas are rare tumors throughout Europe. Therefore, little attention is drawn to this disease. That makes it important to study tumor-associated key metrics and relate these to known data on penile neoplasias.

MATERIALS AND METHODS

A cohort of 60 well-defined penile invasive carcinomas with known human papillomavirus (HPV) infection status was investigated. Data on tumor type, grading and staging were recorded. Additionally, data on the peri- and intratumoral immune cell infiltrate in a semiquanititave manner applying an HE stain were assessed.

RESULTS

Our study showed a significant correlation of immune cell infiltrate and pT stage with overall survival. Therefore, in a subset of tumors, PD-L1 staining was applied. For tumor proportion score (TPS), 26 of 30 samples (87%) were scored >0%. For the immune cell score (IC), 28 of 30 samples (93%) were defined as >0% and for CPS, 29 of 30 samples (97%) scored >0. PD-L1 expression was not associated with overall survival.

CONCLUSION

PD-L1 is expressed in penile carcinomas, providing a rationale for targeted therapy with checkpoint inhibitors. We were able to show that immune reaction appears to be prognostically relevant. These data enhance the need for further studies on the immune cell infiltrate in penile neoplasias and show that PD-L1 expression is existent in our cohort, which may be a potential target for checkpoint inhibitor therapy.

What Is New in the Pathologic Staging of Penile Carcinoma in the 8th Edition of AJCC TNM Model: Rationale for Changes With Practical Stage-by-stage Category Diagnostic Considerations

For >50 years the tumor, node, metastasis (TNM) classification model of malignant tumors has been the main resource for clinicians, pathologists, radiologists and public health professionals ensuring a homogeneous classification and patients' management based on common staging and prognosis factors. Penile cancer was first included for staging in the third edition of the TNM classification with several changes in the last version, the 8th edition of the AJCC TNM Manual, in 2017. Some changes in the pT category were done due to recent knowledge regarding the prognostic importance of anatomical level of invasion, vascular and perineural invasion and tumor grading. These changes must be interpreted in the light of a required understanding of the complex anatomy of penile compartments especially their histological boundaries, the morphological differences of each level needed for the correct classification, the heterogeneity of penile squamous cell carcinomas and an adequate criticism of the current model used by the TNM system. We present here a series of stage-by-stage category diagnostic considerations based on the clinical experience acummulated over the years of applying the different TNM staging classifications in our large clinical practice. Some discrepancies will need well-designed prospective studies for im4proving the actual classification.

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.