Favorable GU, GI toxicity after prostate radiotherapy plus seed implants
MedWire News: Men can expect favorable rates of early genitourinary (GU) and gastrointestinal (GI) toxicity after combined prostate cancer treatment with intensity-modulated radiation therapy (IMRT) and radioactive seed implants, say researchers.
"This combined modality treatment offers several theoretical advantages," say Russell Fuhrer (Allegheny General Hospital, Pittsburgh, Philadelphia, USA) and colleagues.
These advantages include the ability to overcome intrafractional prostate motion with the use of implanted seeds, and a reduction in the time of standard IMRT treatment from 9 to 5 weeks, they add.
However, existing studies show mixed toxicity effects of this treatment combination. Thus, Fuhrer et al assessed the toxicity profiles of 67 patients treated with image-guided- (IG) IMRT plus prostate seed implant boost (brachytherapy) at their institution.
Treatment consisted of 4500 cGy (n=65) or 5040 cGy (n=2) daily external beam radiation to the prostate followed by permanent radioactive seed implantation after a median interval of 22 days.
GU, GI, and sexual function were assessed using validated tools, and acute (early) and late toxicities were defined as those occurring within, and 12 months after the date of brachytherapy.
After a median 28.2-month follow-up, no patients had developed Grade 4 or 5 toxicities indicating life-threatening consequences or death, respectively.
The combined incidence of early and late Grade 3 GU toxicity was 6%, manifesting as one case of urinary frequency, and three cases of late urinary obstruction. No patient required transurethral resection of the prostate, report the researchers.
A total of 3% of men experienced Grade 3 acute and late GI toxicity including one case of late diarrhea and one case of rectal bleeding. However, among the 18 cases who reported at least one episode of (any Grade) rectal bleeding, only 10 could be attributed to the radiotherapy.
Incidence of Grade 2 toxicity was low, with six GU (urinary obstruction and gross hematuria) and five GI (bleeding) cases, all of which were treated without surgical intervention.
Before treatment, 54 of the 67 patients had erectile function, 30 of whom were classified as potent (a Sexual Health Inventory for Men score of 13 or above). For the 25 patients with available follow-up information on sexual function, estimated 3-year potency preservation was 66.5%.
This "common" treatment technique for intermediate-risk prostate cancer "seems to be favorable," conclude Fuhrer and team.
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By Sarah Guy