22 Penis cancer

Penis cancer

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THE GEC ESTROHANDBOOKOF BRACHYTHERAPY | Part II Clinical Practice Version 1 - 15/07/2022

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Figure 6: HDR brachytherapy a) Tumor at presentation

b) Implant in process: shows entrance and exit templates with fixation “nuts” on the entrance side to screw into the template and lock the needles in place c) Implant stabilized and ready for treatment. The urinary catheter is in place, and the needles locked into the template to prevent displacement. In the 4 corners of the template, needles that will not be used for treatment delivery have been positioned and locked into both templates to prevent the spacing of the templates from changing d) Dose distribution: 100% red, 125% blue, 150% orange. 5 mm of bolus wrapping penis, with 7 needles exterior to penis e) Appearance of penis 2 months after treatment f) Another patient 6 years post treatment

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Figure 5: HDR brachytherapy

urethral visualization for planning (Figure 5). a) tumor at presentation b) Implant in process: shows entrance and exit templates with fixatio “nuts” on the entrance side to screw into the template and lock the needles in place c) Implant stabilized and ready for treatment. The urinary catheter is in place, and the needles locked into the template to prevent displacement. In the 4 corners of the template, needles that will not be used for treatment delivery have been positioned and locked into both templates to prevent the spacing of the templates from changing d) Dose distribution: 100% red, 125% blue, 150% range. 5 mm of b lus wrapping penis, with 7 needles exterior to penis e) Appearance of penis 2 months after treatment f) Another pa ient 6 years post treat ent HDR template procedure This is very similar to the above described LDR procedure. The important difference is that the spacing of the needles and planes for HDR should generally be closer than for LDR, in the range of 9-12 mm. For both HDR and PDR, since dose optimization is readily accomplished by adjusting dwell times, the needles and planes do not necessarily need to be equidistant as in a manually- loaded LDR procedure. In our experience, one pair of 5cm x 5cm templates is sufficient, with holes drilled every 3-4mm. 17-gauge steel needles are employed with both entrance and exit template guidance. For HDR, the wider spacing (12 mm) would be chosen for needles that bracket the urethra. Needles are inserted as required to cover the tumour, again beginning with the one consideredmost critical with respect to the urethra. Exterior needles adjacent to the tumor but not penetrating penile tissue can also be used as described in the LDR scenario (Figure 6). Bolus such as superflab should be placed between these needles and penile tissue to ensure adequate dose build-up. For HDR brachytherapy planning, CT simulation is essential for dose calculation and can be performed immediately following the procedure. Slices should be nomore than 1.2mm thick and should be oriented perpendicular to the implant needles. We recommend urethral catheter contrast. HDR surface mold Surface mold treatment should be restricted to superficial tumours (Tis or T1a) not more than 3mm thick. Published experience with HDR surface mold treatment for penile cancer is very limited. Treatment can be delivered with either a custom-made