Sixty-four patients with carcinoma of the penis and clinically negative nodes (N0, N1-2a) had either bilateral groin node dissection (BGND), radiotherapy (RT) to the groin or surveillance in a prospective nonrandomized study on a sequential basis. The tumors were classified according to TNM staging and showed T1, T2 and T3 lesions in 24, 20, 20 patients, respectively, while their node status was N0 in 37 and N1-2A in 27 patients. The tumor grade was G1, G2 and G3 in 10, 30 and 24 patients, respectively. Of these patients 27 had BGND, 18 RT and 19 surveillance. The BGND group showed positive nodes in 4 (14%) patients: 1 with T2 and 3 with T3, and 2 each with N0 and N1-2A status. The 5-year survival was analyzed in terms of primary (T), node status (N), and grade (G) of the tumor and showed 79, 75 and 50% in G1, G2 and G3 tumors, respectively. The overall 5-year survival rate was 74, 66 and 63%, in the BGND, RT and surveillance groups, respectively. Furthermore, analysis of the survival rates in relation to the T and N status in the 3 treatment groups showed identical survival rates for the T category, but for the N category N0 patients had a significantly higher survival rate in the BGND group when compared with the others. In the follow-up relapses occurred in 10 (15%) patients: 7, 2 and 1 in the surveillance, RT and BGND groups, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)