Perineal recurrence of prostate cancer along a brachytherapy needle track: A case report

Metastatic recurrence in an atypical site, such as the perineum, can occur after prostatectomy, cryotherapy, or brachytherapy, but is uncommon. To our knowledge, this is only the third case of perineal recurrence of prostatic cancer along a low dose rate brachytherapy needle track. A 64-year-old man was referred to an urologist with an increased PSA of 6.9ng/mL in December 2008. There were no urinary symptoms. Prostatic biopsies revealed a Gleason 6 adenocarcinoma (3+3), and he was treated with low dose rate brachytherapy in May 2009. Sixty-seven seeds of iodine 125 were loaded under ultrasound control, and the PSA subsequently fell to a nadir of 1.19ng/mL in November 2015. Eight years (May 2017) after the initial treatment, the PSA rose to 5.2ng/mL. Pelvic MRI and choline PET revealed a nodule in the region of the left internal obturator muscle. Nodule biopsies confirmed prostatic origin. This perineal recurrence is thus most likely related to seeding of tumour cells along the track of a brachytherapy needle. To our knowledge, this is only the fourth case of perineal recurrence of prostatic cancer along a low-dose rate brachytherapy needle track. Perineal recurrence of prostatic cancer along a LDR brachytherapy needle track can occur. Improved imaging techniques may help to identify this type of recurrence earlier and optimise treatment.