To Örebro University

PURPOSE: The aim of this study was to examine the risk of HPV-associated oral cavity, oropharyngeal or anal cancer in men with penile cancer to test the hypothesis of an increased risk to develop a second HPV-associated cancer later in life.

MATERIAL AND METHODS: We conducted a population-based register study including all men in Sweden diagnosed with penile cancer between 2000 and 2012. For each patient, six men without penile cancer were matched based on age and county of residence. Data were retrieved from Swedish cancer and population registers, to assess the risk of oral cavity, oropharyngeal or anal cancer in patients with penile cancer. Cox proportional hazard models were used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs). Risks in men with penile cancer were also compared with the background Swedish male population by use of standardized incidence ratios.

RESULTS: In total, 1634 men with and 9804 without penile cancer were included in the study. Among men with penile cancer, four men were subsequently diagnosed with oral cavity cancer, one with oropharyngeal cancer and one with anal cancer. Corresponding numbers among the penile cancer-free men were ten, two and three, respectively. There was evidence of an increased risks of all three cancers under study with an HR of 2.84 (95% CI 0.89-9.06) for oral cavity cancer, 3.66 (95% CI 0.33-40.39) for oropharyngeal cancer and 2.34 (95% CI 0.24-22.47) for anal cancer. When comparing the incidence of these malignancies between penile cancer patients and the background population, the patterns of association were similar.

CONCLUSIONS: Our findings indicate that men with penile cancer are at an increased risk of a second HPV-associated cancer of the oral cavity, oropharynx and anal canal. Considering that our study was based on small numbers reflecting the rarity of these cancers, larger studies are needed to confirm our findings.

PURPOSE: To assess the long-term risks of infectious and thromboembolic events following inguinal (ILND) and pelvic (PLND) lymph node dissection in men with penile cancer.

MATERIAL AND METHODS: A total of 364 men subjected to ILND with or without PLND for penile cancer between 2000 and 2012 were identified in the Swedish National Penile Cancer Register. Each patient was matched based on age and county of residence with six penile cancer-free men. The Swedish Cancer Register and other population-based registers were used to retrieve information on treatment and hospitalisation for selected infectious and thromboembolic events. Hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated using Cox proportional hazard models with multiple imputation.

RESULTS: The risk of infectious events remained increased for more than five years postoperatively in men with penile cancer compared with matched controls. The palpable nodal disease was the only predictor of these events, with risk increasing with the cN stage. The HR at one, three and five years and six months postoperatively was 8.60 (95% CI 5.16-14.34), 4.02 (95% CI 2.65-6.09) and 1.93 (95% CI 1.11-3.38), respectively. An increased risk of thromboembolic events persisted for three years postoperatively. The HR at one and three years postoperatively was 13.51 (95% CI 6.53-27.93) and 2.12 (95% CI 1.07-4.20). The results correspond well with the over-prescription of anticoagulants observed during this period. An association with bulky disease (cN3) was observed.

CONCLUSIONS: Lymph node dissection for penile cancer is associated with an increased risk of infectious and thromboembolic events. The findings of this population-based study show that the risks of these events remain increased more than five years for infectious and three years for thromboembolic events. Improved awareness of long-term complications following ILND is of importance both among patients and care givers to ensure early detection and treatment.

BACKGROUND: Penile cancer (PeCa) is a rare but aggressive disease where lymph node metastases (LNM) represent the most significant prognostic factor. Accurate identification of LNM remains a clinical priority, but traditional imaging and clinical parameters often fail to detect occult LNM. Soluble immune checkpoint proteins (sICs) have recently emerged as potential non-invasive biomarkers in various malignancies, although unexplored in PeCa. The primary aim of this study was to explore the value of a panel of 14 sICs for predicting LNM in PeCa. The secondary aim was to compare plasma sIC levels between PeCa patients and cancer-free controls.

METHODS: Using ProcartaPlex immunoassays, BTLA, IDO, LAG-3, HVEM, PD-1, PD-L1, PD-L2, TIM-3, CD80, CTLA-4, GITR, CD27, CD28, and CD137 were measured in plasma from 284 PeCa patients and 45 cancer-free controls. PeCa patients were divided into a training set (n=202) and a test set (n=82). A prediction model for LNM was created using logistic regression.

RESULTS: Overall accuracy of the prediction model reached 77.5% (95% CI: 70.9 - 83.3) for the training set, yielding 8.9% sensitivity and 99.3% specificity in predicting LNM. Upon validation using the test set, the accuracy decreased to 62.2% (95% CI: 50.8-72.7) with 17.9% sensitivity and 85.2% specificity. When comparing PeCa patients and cancer-free controls, four inhibitory sICs (IDO, TIM-3, CD80, and CTLA-4) were found at significantly higher levels in the PeCa group. Due to the rarity of the disease, the main limitation of the study is the small number of patients with LNM.

CONCLUSION: Our study provides no evidence that sICs can predict LNM in PeCa, although four inhibitory sICs were significantly elevated in PeCa patients compared to cancer-free controls, suggesting systemic immunosuppression associated with tumor presence, consistent with findings in other malignancies. Studies with larger cohorts are warranted to clarify the prognostic significance of sICs in PeCa.