前立腺がんに対する初めての有効な術後補助化学療法 (Abstract LBA5002)

標準治療にドセタキセルを追加することにより高リスク局所前立腺がんの生存率が改善する

Adding docetaxel to standard care improves survival for men with high-risk, localized prostate cancer

標準的なホルモン療法および放射線療法にドセタキセルを追加することにより高リスク局所前立腺がん患者の死亡リスクが軽減する、と第51回American Society of Clinical Oncology年次集会で発表された。この第III相スタディにおいて、高リスク局所進行前立腺がん患者562人が標準治療（放射線療法と2年間のホルモン療法の併用）または標準治療後にドセタキセル化学療法を受ける群にランダムに割り付けられた。ドセタキセルは放射線療法終了後1か月から始まり、18週間投与された。平均追跡期間5.5年の後に標準治療群では52人が死亡し、ドセタキセル群では36人であった。4年全生存率は標準治療群で89%であり、ドセタキセル群では93%であった。ドセタキセルはまた、再発リスクも低下させた－5年無病生存率は標準治療群で66%であり、ドセタキセル群では73%であった。今回のスタディは局所前立腺がんの術後補助化学療法において化学療法が役目を果たすことを示した初めてのものであり、時間と共に多大な生存率への有益性を認めるであろう、と筆者らは述べている。

A phase III study found that adding docetaxel chemotherapy to standard hormone and radiation therapy reduces the risk of death for men with high-risk, localized prostate cancer according to researchers at the American Society of Clinical Oncology's 51st Annual Meeting. At an average follow-up of 5.5 years, four-year overall survival rates were 89% in the standard therapy group vs. 93% in the docetaxel group.

"This study is the first indication that chemotherapy has a role in the adjuvant treatment of localized prostate cancer, and we also expect to see an even bigger survival advantage over time," said lead study author Howard Sandler, M.D., a professor of radiation oncology at the Cedars-Sinai Medical Center in Los Angeles, CA. "This finding could improve outcomes for thousands of men. At the same time, chemotherapy carries a modest increase in side effects, so it is important that physicians discuss the balance of benefits and risks with their patients."

The goal of adjuvant therapy is to lower the risk of recurrence and improve overall survival. Among the most common cancers – lung, breast, colorectal, and prostate – prostate cancer is the only disease without an established adjuvant chemotherapy regimen.

In the study, 562 men with high-risk, locally advanced prostate cancer were randomly assigned to treatment with standard therapy (radiation therapy plus two years of hormone therapy) or standard therapy followed with docetaxel chemotherapy. Docetaxel was given for 18 weeks, starting a month after radiation therapy.

After an average follow-up period of 5.5 years, 52 deaths occurred in the standard therapy group compared to only 36 deaths in the docetaxel group. The four-year overall survival rates were 89% in the standard therapy group compared to 93% in the docetaxel group. Docetaxel also reduced the risk of relapse ─ the five-year disease-free survival rates were 66% in the standard therapy group vs. 73% in the docetaxel group.

Patient follow-up will continue to determine the long-term benefit of adjuvant chemotherapy in this setting, and an analysis of quality of life data will be performed at a later time.

"Adjuvant chemotherapy has delivered major survival gains to people with several of the most common types of cancer, and now we're finally seeing the same with prostate cancer," said ASCO Expert Charles J. Ryan, M.D.. "Here we have a powerful new use for a long-established therapy. It's an advance that would not have been possible without federally funded clinical trials."

This study received funding from The National Institutes of Health, Sanofi, and AstraZeneca.