Treatment results and prognostic factors in 101 men treated for squamous carcinoma of the penis.

PURPOSE: This retrospective study was performed to assess the treatment outcome and prognostic factors in 101 men with invasive squamous carcinoma of the penis treated at the Royal Marsden Hospital between 1960-1990.

METHODS AND MATERIALS: The tumor was confined to the glans penis (T1) in 79 patients, 82 were node negative (N0), and two patients had distant metastases at presentation. The histology was Grade 1 (G1) in 36, Grade 2 (G2) in 18, Grade 3 (G3) in 28, and unknown in 19 patients. Node-positive disease was commoner in patients with G3 (p = 0.02) or T2/3/4 tumors (p = 0.007). Treatment for the primary tumor was external beam radiotherapy (EBRT) in 59, interstitial brachytherapy in 13, and partial or total penectomy in 29 patients. The median dose, dose/fraction, and treatment time for EBRT was 60 Gy, 2 Gy/fraction, and 46 days, respectively. Eighty patients received no inguinal node treatment, 13 had EBRT (4 with chemotherapy), and 8 underwent groin dissection at presentation.

RESULTS: During a median follow-up of 5.2 years (2 months-22 years), 56 patients died (penile cancer 31, intercurrent illness 23 and unknown cause 2), giving 10 year overall and cause-specific survival (CSS) of 39 and 57%, respectively. Adverse prognostic factors for CSS on univariate analysis were G3, ulcerative/fungating or T2/3/ 4 tumors, node positive, Jackson's Stage 2/3/4, and surgical treatment for the primary. All but the last two were significant independent prognostic factors for CSS on multivariate analysis. Penile or perineal recurrence or residual disease after initial treatment was seen in 36 out of 98 evaluable patients, giving a 10-year local failure rate (LFR) of 45%. Local failure after initial treatment was successfully salvaged in the majority (26 out of 36) of patients with further surgery or radiotherapy, and local control was achieved ultimately in 74 out of 77 T1, 7 out of 12 T2; 3 out of 3 T3, and 3 out of 5 T4 tumors. In the 44 evaluable patients with T1 tumors treated by EBRT the only adverse RT parameter approaching prognostic significance (p = 0.052) was a BED value corrected for recovery of <60 Gy (alpha/beta 10, K = 0.5 Gy/day, mean = 21 days).

CONCLUSION: Invasive squamous carcinomas of the penis carry a significant risk of loco-regional recurrence after initial radiotherapy and this can be successfully salvaged in most patients with further treatment. This mandates close follow-up to detect loco regional recurrence early.