Lymphovascular and perineural invasion are risk factors for inguinal lymph node metastases in men with T1G2 penile cancer

Abstract

Purpose: To analyse the risk of inguinal lymph node (ILN) metastases in T1G2 penile cancer stratified by lymphovascular invasion (LVI), perineural invasion (PNI) and tumour size. Methods: Retrospective study of men with localised T1G2 penile cancer with non-palpable lymph nodes and no local recurrence during follow-up at six European institutional high-volume centres was performed. ILN involvement was defined as cancer detected during ultrasound-guided fine-needle aspiration cytology, core needle biopsy, dynamic sentinel lymph node biopsy, ILN dissection or inguinal recurrence during follow-up. Uni- and multivariable logistic regression analyses were performed. Results: In the cohort of 554 men with T1G2 penile cancer, from 6 European institutions, ILN metastases were observed in 46/554 men (8%, 95% confidence interval (CI) 6-11%). Men with both, LVI- and PNI- primary cancers had the lowest risk of ILN involvement (6%) whereas men with LVI + or PNI + showed ILN metastases in 22% and 30%. In multivariable regression, men with LVI + or PNI + had higher odds for ILN metastases compared to men with LVI- and PNI- (OR 3.9, 95% CI 1.6-9.0, p value < 0.01) Tumour size was not associated with ILN risk (OR 1.01 95% CI 0.99-1.04, p = 0.17). Conclusion: Approximately, one out of ten men with T1G2 overall and one out of four men with either LVI + or PNI + still have ILN metastases despite being clinically node negative. Therefore, invasive ILN staging should strongly be recommended in T1G2 with LVI + or PNI + but importantly, must be discussed in patients with T1G2 with LVI- or PNI-.