Similar outcomes with neoadjuvant and concurrent sequencing of ADT, prostate RT
medwireNews: Biochemical relapse-free survival (bRFS) and overall survival (OS) rates are comparable in men with localized prostate cancer (LPCa) who start androgen-deprivation therapy (ADT) before or at the same time as dose-escalated prostate radiotherapy (RT), phase 3 study data show.
“On the basis of these results, both neoadjuvant and concurrent initiations of short-term ADT with dose-escalated [prostate] RT are reasonable standards of care for LPCa,” write Shawn Malone (The Ottawa Hospital Regional Cancer Center, Ontario, Canada) and co-authors in the Journal of Clinical Oncology.
The trial included 215 patients with newly diagnosed LPCa with a Gleason score of 7 or lower, clinical stage T1b to T3a, and a prostate-specific antigen level below 30 ng/mL who were randomly assigned to 6 months of treatment with neoadjuvant and concurrent ADT starting 4 months before dose-escalated prostate RT (neoadjuvant group).
The outcomes of this group were compared with those of 217 patients who were randomly assigned to received 6 months of concurrent and adjuvant ADT starting at the same time as prostate RT (concurrent group).
At 10 years, the researchers found that there was no significant difference between the two groups in either bRFS, OS, or cancer-specific survival.
Specifically, the 10-year bRFS rates were 80.5% and 87.4% in the neoadjuvant and concurrent groups, respectively, while the corresponding 10-year OS rates were 76.4% and 73.7% and the 10-year cancer-specific mortality rates were 2.0% and 1.9%.
There was also no significant difference between the neoadjuvant and concurrent regimens in the incidence of late RT-related grade 3 of higher gastrointestinal toxicity (2.5 vs 3.9%) or genitourinary toxicity (2.9% in both groups).
Malone et al note that the relapse rates they observed were “much lower than anticipated because of limited information on the long-term efficacy of dose-escalated RT at the time of study design.”
“Consequently, our study lacked sufficient power to achieve conventional levels of statistical significance, despite showing some evidence of improved bRFS with use of concomitant and [adjuvant ADT],” they say.
The team concludes: “Irrespective of the sequencing strategy chosen, these results demonstrate encouraging long-term oncologic outcomes with the combination of short-term ADT and dose-escalated RT in intermediate-risk PCa.”
They add that their findings “support flexibility in tailoring the sequence of ADT and RT to optimize treatment adherence and convenience for patients with LPCa.”
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