ホルモン療法と放射線療法の併用により前立腺がんの生存率が改善する（Abstract #: CRA4504）

ホルモン療法に放射線療法を併用することにより局所進行前立腺がん患者の生存率が改善する
Adding radiation therapy to hormone therapy improves survival in men with locally advanced prostate cancer
アンドロゲン除去療法（ADT；ホルモン療法としても知られる）に放射線療法を併用することにより、局所進行または高リスクの前立腺がん患者の前立腺がん死のリスクがADT単独と比較し43%低下したとのphase IIIスタディの結果が第46回ASCO学会で発表された。局所進行または高リスクの前立腺がん患者をADT単独療法（602人）またはADTと放射線療法の併用（603人）を受ける群に無作為に割り付けた。7年後に生存していたのはADT単独群では66%であり、ADTと放射線療法の併用群におけるその割合は74%であった。ADT単独群では26%が前立腺がんにより死亡したのに対し、ADTと放射線療法の併用群においては10%であった。ADTと放射線療法の併用群患者はADT単独群患者よりも生存期間が平均6ヵ月延長した。有意な長期のGI毒性は両群間で差がなかった。研究者らは、10年間の前立腺がんによる死亡（10年間の疾患特異的累積死亡率）はADTと放射線療法併用群においてADT単独群よりも少ないであろうと推測している（それぞれ15%と23%）。
Full Text

A Phase III study presented at ASCO's 46th Annual Meeting reports that adding radiation therapy to androgen deprivation therapy (ADT; also known as hormone therapy) reduces the risk of dying from prostate cancer by 43 percent in men with locally advanced or high-risk prostate cancer compared to ADT alone.

"This study will challenge the prevailing dogma of only using hormone therapy for locally advanced prostate cancer," said Padraig Warde, MBChB, deputy head of the radiation medicine program at the University of Toronto's Princess Margaret Hospital. "We found that men who received the combination lived longer, and were less likely to die of their prostate cancer than those who had only hormone therapy. These results suggest that adding radiation therapy to the treatment plan for these patients could become part of standard therapy and should be considered."

Some physicians and clinical guidelines recommend radiation with ADT as a treatment option for locally advanced prostate cancer. But it has been unclear whether ADT alone was sufficient therapy for these patients, and whether the side effects of radiation could be avoided. ADT reduces the level of cancer-fueling male hormones in the body, and is standard therapy for men whose disease persists despite local treatment (radiation therapy or surgery).

In this study, men with locally advanced or high-risk prostate cancer were randomly assigned to receive ADT alone (602 men) or ADT plus radiation (603 men). After 7 years, 66 percent of men who had ADT alone were still alive, compared with 74 percent of those who had received ADT plus radiation. Among those in the ADT-only group, 26 percent died from their prostate cancer, versus 10 percent of those who received ADT plus radiation. Patients who received ADT plus radiation lived 6 months longer on average than those who received ADT alone. There was no increase in significant, long-term GI toxicity between treatment groups.

The researchers projected that fewer men (15 percent) who received ADT plus radiation would die from their prostate cancer over 10 years (10-year cumulative disease specific death rate) compared to 23 percent with ADT alone.