High dose rate prostate brachytherapy: the California Endocurietherapy (CET) method

To describe the rationale, protocol and procedure for the treatment of prostate cancer using high dose rate brachytherapy (HDR-BT) and a non-fixed template technique.

Between July 1991 and December 1998, 491 patients with carcinoma of the prostate were treated using HDR-BT and a non-fixed template technique. AJC stages T(1C)-T(3B), patients with prior transurethral resections of the prostate (TURP) and gland volumes >60 cm(3), were included. Flexible cystoscopy, fluoroscopy and transrectal ultrasound (TRUS) were used and 17 flexiguides were inserted through the perineum. Dosimetry was carried out using localization films. Treatment volume was defined at 4-6 mm outside the peripheral catheters. BT consisted of two implants, separated by 1 week, with two fractions given per implant for a total of four HDR fractions. Dose prescription to the treatment volume was 6 Gy (HDR) per fraction, with an additional dose of 0.5 to 0.75 Gy given where required.

Patients with glands >60 cm(3), narrow pubic arches and TURP defects were treated satisfactorily. Symptoms of urinary irritation occurred with variable intensity and abated rapidly 2 weeks after the procedures. There was no high-grade chronic rectal morbidity and most patients reported no rectal symptoms or treatment-related chronic urinary incontinence.

The non-fixed template technique allowed flexibility in flexiguide placement to encompass large glands (>60 cm(3)), extracapsular extension and seminal vesicle involvement without the need for additional flexiguides. Also, small pubic arches and TURP defects posed little problem in positioning the flexiguides. This versatility resulted in complete treatment volume coverage of the prostate.