Brachytherapy offers superior cancer control for prostate patients
MedWire News: Brachytherapy (BT) achieves superior cancer control in prostate cancer patients with low- or intermediate-risk disease compared with external beam radiotherapy (EBRT), but at the cost of higher rates of urinary toxicity, report researchers.
In a study which directly matched BT-treated and EBRT-treated patients with the same clinical disease features, 5-year disease-free progression rates were higher in patients treated with BT than in those treated with EBRT, and remained higher after 10 years.
“BT for both low-risk and selected intermediate-risk cancers achieves exceptional cure rates,” say Tom Pickles and colleagues, from the BC Cancer Agency in Vancouver, Canada.
“Even with dose escalation, it will be difficult for EBRT to match the proven track record of BT seen over the past decade,” they write in the International Journal of Radiation Oncology Biology Physics.
However, the research team reports worse late urinary toxicity in patients treated with BT compared to those treated with EBRT, with acute grade 3 genitourinary toxicity seen in 2.9% and 0.7% of BT and EBRT patients, respectively.
The researchers matched 139 BT-treated patients with 139 EBRT-treated patients, by era of diagnosis (1998–2001), Gleason score, T stage, percentage of positive biopsy core samples, and use and duration of androgen deprivation therapy (ADT).
They assessed biochemical control (bNED) rates among the cohort, using the definition for biochemical failure of a prostate-specific antigen nadir plus 2 ng/ml.
After 5 years of follow-up, the bNED rates were 95.2% in the BT group and 84.7% in the EBRT group. These rates were similar when the researchers divided patients into low- and intermediate-risk groups, at 94% and 88% for low-risk patients receiving BT and EBRT, respectively, and 100% and 78% for intermediate-risk patients.
The researchers also found that use of ADT after relapse was higher in the EBRT group than the BT group, at 8% versus 5%. However, ADT was included in the protocol for BT-treated patients, but not EBRT patients, which may be limit these results, say Pickles et al.
The team concludes that, until randomized studies comparing BT with either EBRT or surgery are available, their nonrandomized matched-pair comparison study and others like it “can provide the yardstick by which patients and physicians can make informed decisions about which treatment is likely to best suit them.”
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By Sarah Guy