Myths and fallacies in permanent prostate brachytherapy.
Because there are competing modalities to treat early-stage prostate cancer, the constraints or deficiencies of one modality may be erroneously applied to others. Some valid concerns arising from surgery and external beam therapy, which have been falsely transferred to brachytherapy, are constraints based on patient age, clinical and pathological parameters, patient weight, and size of prostate. Although the constraints have a valid basis in one modality, knowledge of the origin and mechanism of the constraint has provided a means to circumvent or overcome it in brachytherapy. Failures as measured by biochemical no-evidence of disease (bNED) survival may be attributed to extracapsular disease extension. Such extension often expresses itself in surrogate parameters such as a high percentage of positive biopsies, perineural invasion, or the dominant pattern in Gleason score histology. Failures due to such factors may be prevented by implanting with consistent extracapsular dosimetric margins. Some presumed limitations on prostate brachytherapy originated from data on patients implanted in the first few years the procedure was being developed. Most of the urinary morbidity and a significant part of the decrease in sexual function observed may be avoided by controlling the dosimetry along the prostatic and membranous urethra and at the penile bulb.
Butler
Wayne M
WM
Schiffler Cancer Center, Wheeling Hospital, Wheeling, WV 26003-6300, USA. wbutler@wheelinghospital.com
Merrick
Gregory S
GS
D000367:Age Factors; D000368:Aged; D001918:Brachytherapy; D007172:Erectile Dysfunction / Q000517:prevention & control; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D011879:Radiotherapy Dosage