Hollywood, Florida — The National Comprehensive Cancer Network (NCCN) has issued new treatment guidelines for penile cancer.
"The first thing people ask me is why develop guidelines for such a rare cancer," said Philippe E. Spiess, MD, genitourinary oncologist at the H. Lee Moffitt Cancer Center in Tampa, Florida.
In 2010, an estimated 1250 new cases of penile cancer were diagnosed in the United States and there were about 310 related deaths. Penile cancer accounts for 0.4% to 0.6% of all malignant neoplasms in the United States and Europe.
Dr. Spiess presented highlights of the guidelines here at the NCCN 18th Annual Conference.
There is a high degree of heterogeneity in the way penile cancer is treated in North America and globally, he explained. "The standard of care remains complete tumor excision and eradication of negative margins."
However, there has been increasing consideration of less or noninvasive management of primary penile tumors, based on stage and grade, he added.
Less and Noninvasive Therapy
For carcinoma in situ and superficial verrucous carcinoma, a British study showed that 5-fluorouracil or imiquimod produced response rates of 60% to 70% at 5 years (World J Urol. 2009;27:179-187). In this setting, CO2 and Nd:YAG laser ablation can also be used, although retreatment rates are quite high (about 20% to 30%), explained Dr. Spiess.
Total gland resurfacing and wide local excision with circumcision are also options.
There is some evidence for the use of topical therapies. In a recent retrospective review of all primary and recurrent cases of penile carcinoma in situ treated with topical 5-fluorouracil and imiquimod over a 10-year period (Eur Urol. 2012;62:923-928), "the response rates were excellent," said Dr. Spiess. "A complete response was seen in 57% of the patients, with a partial response in 14%."
No response was seen in the remaining 29.5% of patients, but none of the patients recurred or progressed. Toxicity was also low; 10% of patients reported local toxicity and 12% reported an adverse event.
Another study, looking at penile-preserving surgery for patients with penile Tis and PT1 tumors, found that there was a recurrence rate of 21.4% in both subgroups (J Urol. 2011;186:1303-1307). At 5 years, 13.8% of patients had a late recurrence, but none of the patients with pTis tumors had progressed to invasive or metastatic disease.
"These patients can recur fairly late, so it is important to follow them for at least 10 years," Dr. Spiess pointed out.
"As far as penile-preserving therapy, the take-home message is that clinical stage is everything," Dr. Spiess explained. However, he went on to emphasize that "it has to be a patient with a small superficial lesion, where you can obtain negative margins. If you can't, then you need to look at more radical options in surgery."
Another treatment option is brachytherapy. A recent French study found a 10-year penile recurrence rate of 20% and a 10-year inguinal recurrence rate of 11% (Int J Radiat Oncol Biol Phys. 2009;74:1150-1156). However, "centers of excellence that have experience with penile brachytherapy are few and far between," he cautioned. "That's why the guidelines...are somewhat cautious in making recommendations until we see a wider experience using penile brachytherapy."
He emphasized the importance of stringent surveillance after radiotherapy to the penis; up to 40% of patients who receive radical radiotherapy will eventually need surgery for disease recurrence. Surgery in this population can be challenging because irradiated tissues are brittle and poorly vascularized, making them less than ideal for grafting.
Sentinel Node Biopsy
Dr. Spiess discussed the concept of sentinel lymph node biopsy in penile cancer, which was proposed more than 30 years ago. One study reported a false-negative rate of 18% using a combined preoperative injection of technetium-99m labeled sulfur colloid and isosulfan blue dye (J Urol. 2002;168:76-80).
A more recent prospective study found a sensitivity of only 71%, with 2 false-negative results reported (J Urol. 2007;177:2157-2161). But a review found that false-positive results can be minimized with preoperative ultrasound and fine-needle aspiration cytology on suspicious nodes (World J Urol. 2009;27:197-203).
However, this technique has not yet been embraced in this setting. "We are somewhat cautious about promoting this technique, although clearly it is something very interesting and something that can be used at a center that has high expertise in sentinel lymph node biopsy," said Dr. Spiess. "At this point, it is not being widely used in North American centers."
National Comprehensive Cancer Network (NCCN) 18th Annual Conference.