Novel portable apparatus for outpatient high-dose-rate (HDR) brachytherapy in penile cancer

Abstract

Background: Penile squamous cell carcinoma (PSC) is traditionally treated with surgical resection with significant morbidity. Penile sparing approaches, such as brachytherapy, require expertise, prolonged inpatient stays, poor patient convenience, and heterogenous plans with variable long-term toxicity. In this study, we describe the protocol for novel portable apparatus created for PSC, allowing outpatient hybrid interstitial/surface brachytherapy, improving homogeneity and patient convenience.

Methods: A portable brachytherapy apparatus was developed utilizing a foley catheter, prostate template, 6F interstitial catheters, 5 mm bolus, and a jock strap. The apparatus allowed for internal and external catheter placement housed in a jock strap to allow mobility and defecation without affecting the implant. High-dose-rate brachytherapy was performed as an outpatient.

Results: The apparatus was then used on a 62-year-old male with cT2pN0M0 (stage IIA) PSC with bilateral glans and urethral meatus involvement, who elected for definitive brachytherapy (4000cGy in 10 fractions over 5-days). Given external dwell positions, heterogeneity correction of the template was calculated (AAPM TG186) with <2% variation. Patient had minimal impact on his active lifestyle during treatment and had complete clinical response at 3-months. Grade 2 skin desquamation resolved at 2-months, with no necrosis. At 6-months, he was able to resume sexual intercourse, and at 12-months, he remained disease-free with sexual and urinary function intact.

Conclusions: Novel portable implant allows for improved patient convenience, reduced inpatient stay, capable of optimizing dosimetry with hybrid brachytherapy. This outpatient treatment allows the opportunity to increase fractionation, offering high local-control and lower toxicity. Future studies utilizing this apparatus for more fractionated regimens with further lower dose-per-fraction (∼3 Gy/fraction) is recommended.

Keywords: Brachytherapy; High-dose-rate; Organ-sparing; Outpatient; Penile cancer; Sexual function.