VOL.5
長期内分泌療法は予後がよい  
Duration of androgen suppression in the treatment of prostate cancer.
Author: Bolla M, et al.; EORTC Radiation Oncology Group and Genito-Urinary Tract Cancer Group.
Journal: N Engl J Med. 2009 Jun 11;360(24):2516-27.
Abstract:
BACKGROUND: The combination of radiotherapy plus long-term medical suppression of androgens (> or = 2 years) improves overall survival in patients with locally advanced prostate cancer. We compared the use of radiotherapy plus short-term androgen suppression with the use of radiotherapy plus long-term androgen suppression in the treatment of locally advanced prostate cancer.

METHODS: We randomly assigned patients with locally advanced prostate cancer who had received external-beam radiotherapy plus 6 months of androgen suppression to two groups, one to receive no further treatment (short-term suppression) and the other to receive 2.5 years of further treatment with a luteinizing hormone-releasing hormone agonist (long-term suppression). An outcome of noninferiority of short-term androgen suppression as compared with long-term suppression required a hazard ratio of more than 1.35 for overall survival, with a one-sided alpha level of 0.05. An interim analysis showed futility, and the results are presented with an adjusted one-sided alpha level of 0.0429.

RESULTS: A total of 1113 men were registered, of whom 970 were randomly assigned, 483 to short-term suppression and 487 to long-term suppression. After a median follow-up of 6.4 years, 132 patients in the short-term group and 98 in the long-term group had died; the number of deaths due to prostate cancer was 47 in the short-term group and 29 in the long-term group. The 5-year overall mortality for short-term and long-term suppression was 19.0% and 15.2%, respectively; the observed hazard ratio was 1.42 (upper 95.71% confidence limit, 1.79; P=0.65 for noninferiority). Adverse events in both groups included fatigue, diminished sexual function, and hot flushes.

CONCLUSIONS: The combination of radiotherapy plus 6 months of androgen suppression provides inferior survival as compared with radiotherapy plus 3 years of androgen suppression in the treatment of locally advanced prostate cancer.
(Sanda MG, et al. Quality of Life and Satisfaction with Outcome among Prostate-Cancer Survivors New Engl J Med 2008; 358:1250-1261)
コメント:
前立腺癌の放射線治療には、内分泌療法を併用したほうがよいことがレベルIのエビデンスであるが、では短期{6ヶ月}と長期{3年}では予後に差があるのか、大規模無作為割付試験がEORTCで行われた。この背景には、内分泌療法には合併症が多いことが知られてきたことがある。

対象は、T3癌でPSA18 しかしGleason7が中心であり、日本の放射線治療の対象者とあまりかわらないだろう。

結果は驚くべきことに、内分泌療法を6ヶ月で打ち切ると、有意に生存期間が短かった。すなわち短期治療群ITT 483人のうち観察期間約5年で前立腺癌死が47人、clinical progressionが191人、長期治療群ITT487人のうち前立腺癌死が28人、clinical progressionは122人であった。

放射線治療に内分泌治療を加えると生活の質(QOL)はきわめてよくないことが知られている。(Sanda MG, et al. Quality of Life and Satisfaction with Outcome among Prostate-Cancer Survivors New Engl J Med 2008; 358:1250-1261)
しかし今回の結果からは、lethal phenotypeの前立腺癌ではQOLはよくなくても、放射線治療に加えて、内分泌療法を長期に行ったほうが予後はよいという決定的な結果 が得られたといえよう。
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