Predicting regional lymph node metastasis in carcinoma of the penis: a comparison between fine-needle aspiration cytology, sentinel lymph node biopsy and medial inguinal lymph node biopsy.

Abstract

To evaluate the accuracy of clinical examination and fine-needle aspiration cytology (FNAC) in detecting groin metastases in patients with carcinoma of the penis, and to assess the positive and negative predictive value (PPV, NPV) of a preliminary sentinel lymph-node biopsy (SNB) and biopsy of the most medial of the horizontal group of inguinal lymph nodes (MIN) in selecting patients for an ilio-inguinal block dissection. The study comprised 28 patients (56 groins) with Stage I (one), Stage II (11) and Stage III (16) carcinoma of the penis. All patients underwent a detailed clinical examination followed by FNAC of the palpable inguinal nodes, and were subsequently submitted for block dissection. The MIN, the SN and the rest of the inguinal and iliac nodes were histologically examined separately for metastases. The clinical evaluation had a sensitivity of 74%, a specificity of 61%, a PPV of 57% and a NPV of 77%. The corresponding values for FNAC were all 100%, and the specificity and PPV for both MIN and SN were 100%. The sensitivity and NPV of MIN were higher than for SN, although not significantly so. Clinical examination alone is inaccurate in selecting patients with carcinoma of the penis for block dissection. FNAC is accurate and specific when nodes are palpable; in those with impalpable nodes a preliminary MIN biopsy followed by SNB if the MIN biopsy is negative will accurately select all patients with metastases in the groin nodes. This can be performed by examining frozen sections of the lymph nodes; if positive, block dissection can be carried out at the same time.