Surgical management of the clinically negative contralateral groin when the ipsilateral groin is clinically and pathologically positive in squamous cell carcinoma of the penis
Diagnosis of pathologically positive inguinal nodal disease in squamous cell carcinoma of the penis is the single most important prognostic factor. There however remains variation in practice. This is especially pertinent in the management of the contralateral non-palpable inguinal basin (cN0) when the ipsilateral basin is clinically and pathologically positive (cN+/pN+). In this cohort, our practice is to perform an FNA on the cN+ groin for pathological diagnosis followed by ipsilateral radical inguinal node dissection (ILND) with synchronous dynamic sentinel node biopsy (DSNB) on the contralateral side. ILND is then only undertaken if the sentinel node is pathologically positive. The purpose of this study is to establish the probability of the contralateral inguinal basin being pathologically positive when the ipsilateral side is cN+/pN+.
A prospective DSNB cohort study has been on-going in our institution since 2003. All patients were reclassified according to TNM 7 classification. Management of patients was in a multidisciplinary team setting and the nodal treatment algorithm has not changed over the study. Patients with ipsilateral cN+/pN+ on initial presentation who had a contralateral DSNB were identified. The probability of the contralateral DSNB being positive was calculated. This was compared with the rate of the contralateral basin being pathologically positive when the ipsilateral basin is clinically negative but pathologically positive (i.e. bilateral positive DSNB). Chi squared test was used for statistical analysis.
A total of 614 patients underwent DSNB between 2003-2017. Overall 17.5% were positive. 42 patients were identified with unilateral cN+/pN+. Of this cohort, 16 patients (38%) had pathologically positive disease in the contralateral groin after DSNB. In patients with bilateral cN0 groins, 84 patients (14.6%) had a positive DSNB. Of these, 52 (9%) had a unilaterally positive DSNB and 32 were bilaterally positive (5.5%) (p < 0.01).
There is a statistically significant increased risk of the contralateral inguinal basin being involved if the ipsilateral basin is clinically and pathologically positive. However, the rate of 38% positivity would still support our practice of contralateral DSNB as it avoids the associated morbidity of radical groin dissection in the 62% of patients who would have had a negative result. We therefore continue to recommend using DSNB prior to groin dissection in all clinically negative groins.