External validation of the proposed T and N categories of squamous cell carcinoma of the penis.

OBJECTIVES

The aim of this study was to validate recently proposed modifications to the current TNM classification of penile squamous cell carcinoma (PSCC) by using data from four German urological centers.

METHODS

We identified 89 patients treated for histologically confirmed PSCC between 1996 and 2008 and reclassified them according to the proposed TNM staging revisions. The proposed changes restricted T2 to tumoral invasion of the corpus spongiosum, whereas invasion of the corpus cavernosum was considered as T3. No changes were made to T1 and T4. Furthermore, N1 was limited to unilateral and N2 to bilateral inguinal lymph node involvement regardless of their number. Pelvic lymph node involvement and fixed lymph node were considered as N3 tumors. The range of follow up after initial treatment was 1-142 months (mean 38).

RESULTS

Node-negative cases following the current classification were 65.2% (30/46), 48.5% (16/33) and 87.5% (7/8) for T1, T2 and T3, respectively. According to the proposed classification, N0 cases were markedly reduced in the T3 group (55.5%, 10/18) and relatively changed in the T2 group (56.5%, 13/23). T4 patients had no negative disease status. The 3-year disease-specific survival (DSS) rates for the proposed categories were 85.4%, 71.6% and 62.4% for T1, T2 and T3, respectively. For the current categories, the 3-year DSS rates were 85.4%, 66.9% and 100% for T1, T2 and T3, respectively. The 3-year DSS of the current N categories was 78.7%, 51% and 13.3% for N1, N2 and N3, respectively. According to the newly proposed categories, the 3-year DSS was 70%, 50% and 13.3% for N1, N2 and N3, respectively.

CONCLUSION

Tumor and nodal staging of the newly proposed TNM classification show a more distinctive survival compared to the current one. However, a multi-institutional validation is still required to further corroborate the proposed modifications.