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

Abstract

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. 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. 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). 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-.