VIENNA, Austria-Brachytherapy by catheter-delivered iridium-192 gave equivalent disease-free and overall survival to surgery in a large study of penile cancer reported at the 2017 European Society for Radiotherapy and Oncology (ESTRO) Congress. Unlike glansectomy, however, brachytherapy preserved both structure and function of the penis in most patients.
Alexandre Escande, MD, a radiation oncology resident at the Gustave Roussy Cancer Campus (Villejuif) in France, described his group's single institution study of 201 patients over 45 with histologically confirmed invasive squamous cell carcinoma of the penile glans with follow-up for a median of 10.7 years. All patients were circumcised before brachytherapy using doses between 36.5 and 76 Gy.
"We found excellent results for both overall survival-more than 50 percent at 15 years-and for progression-free or disease-free survival more than 70 percent at 10 years," said Escande, who wrote that overall survival at 5, 10, and 15 years were 79.3 percent, 67 percent, and more than 50 percent, while for disease-free survival the findings were 64.1 percent, 53 percent, and more than one-third.
Local control rates at 5 and 10 years were 82 percent and 75.4 percent, and the rates of penile preservation were 85 percent and 74 percent at these time intervals after treatment. Eighteen patients (12.9%) needed partial surgery and eight (4%) had total penectomies for relapse. Fifty patients (25%) had urethral stenosis needing at least one dilatation and 13 (6%) had "limited surgeries for toxicities."
Escande noted that overall the survival among patients treated with brachytherapy was equivalent to other men of this age group. "This is excellent because it's a cancer of old people and the median age of our population was 62. So, an overall survival of more than 50 percent at 15 years is nearly like the general population.
"For local control rates and penile preservation, we also found an excellent result because nearly all our patients keep their penis at the end of the follow-up with more than three patients out of four with penile preservation."
Brachytherapy vs. Surgery
A small quality-of-life survey among a sample of patients found "good" results with scores between 75 and 80 percent. "Also, nearly all our patients who had sexual activity before keep it after the treatment. So they are very satisfied about that-because when you have total glansectomy, it's very difficult keep sexual activity. Some authors describe psychological effects after total glansectomy," Escande said.
Fewer patients treated with glansectomy had less local relapse, he stated, but it was a big advantage for any patient to keep his penis intact. "It's important for functional and psychological reasons."
He said the findings were welcome and that historic data were incomplete. "No randomized study has been published because it's such a rare disease that it's impossible to do this in a national study or a single center."
Escande suggested the study findings give strong support for the use of brachytherapy rather than surgery for many patients. However, he acknowledged there were still question marks over patient selection.
"From this largest series with a long-term follow-up, we can see that brachytherapy shows a higher local control rate and a high penile preservation rate. However, we have to look at the management of node status-because this is the main prognostic factor for disease-free survival," he explained. The study found lymph node metastasis correlated with poorer overall survival. Also neutrophilia at diagnosis correlated with a higher probability of distant relapse.
Changes to Treatment
When Escande was asked whether his study findings were practice-changing, he said that apart from the lack of randomized trial data there was also a learning curve for practitioners wanting to use brachytherapy for penile cancer.
"Brachytherapy needs anesthesia and needs practitioner experience. So my colleagues have to train before practicing brachytherapy. But I hope my results will help my colleagues find the motivation for doing that in the future. Other preservation treatments are being developed-such as laser therapy-and surgeons are also looking at how to adjust the size of surgery."
His team wrote that the study confirmed the high local control achieved with brachytherapy and the advantage of organ preservation in selected patients-with most local relapses salvaged by "second intent" surgery.
"These results show that brachytherapy is the treatment of choice for selected patients whose cancer has not spread into the corpus cavernosum. It is effective at controlling and eradicating the cancer and allows a high number of men to preserve their penises," Escande noted.
"Another important finding was that if cancer did return, then this could often be dealt with successfully by a second round of brachytherapy or by surgery without men being at higher risk of death from the disease. This suggests that brachytherapy is an adequate upfront, organ-sparing strategy, which is usually associated with only mild to moderate toxicities. Men still have a good body image, and the majority also [had] sexual and urinary function.
"So brachytherapy for penile cancer seems to be a real way of treatment, and I hope it will be the standard of care for the future."
The President of ESTRO, Yolande Lievens MD, PhD, Head of the Department of Radiation Oncology at Ghent University Hospital, Belgium, said: "These are very encouraging results from an excellent study of a large group of men with a rare cancer who were followed up for a long period of time. These findings further endorse the important role of radiotherapy-brachytherapy in this particular situation-in organ-sparing curative approaches to cancer. The use of brachytherapy in this very rare cancer type not only translated into high survival rates of men with this disease, but also ensured that the impact on their quality of life was kept to a minimum."
Peter M. Goodwin is a contributing writer.