TheNew England Journal of Medicine 1997;337:295-300.
Encouraging news for patients with prostate cancer is reported in theJuly 31st issue of the NEJM. Bolla and colleagues show that the additionof Goserelin improves the efficacy of radiation therapy in treatingprostate cancer. Goserelin is a medication that prevents the proliferation of prostate cancer cells by depriving them of testosterone, a hormonewhich stimulates their growth. Because Goserelin blocks the effects of ahormone, its use is often referred to as "hormonal therapy" of prostate cancer.
The study randomized 415 patients to radiation alone or radiation andthree years of Goserelin beginning with the first day of radiation. Thepatients who received Goserelin had significantly longer overall survival anddisease free survival: At five years 79% of the patients treated withGoserelin and radiation were alive compared with 62% in the radiation alone arm. Additionally, of those patients who received Goserelin and were livingat five years, 85% had no evidence of cancer compared with 48% in theradiation only arm.
This trial is encouraging and supports the use of Goserelin onselected patients with prostate cancer However, some caution should be used in interpreting these results in light of numerous previous trials using anti-testosterone therapy in addition to radiation, few of which haveshown a survival advantage to combining the two treatments. The RadiationTherapy Oncology Group (RTOG) sponsored a trial in which nearly 500 menreceived radiation or radiation and 8 weeks of hormonal therapy. This trialfound a benefit to combined therapy in terms of improved local control anddisease free survival but no difference between the two arms with respect tooverall survival. However, the RTOG differed in several respects from theBolla study, including the entry criteria, dosage, duration and type ofhormone therapy.
The challenge for physicians will be to determine exactly whichpatients will benefit from the hormonal agents (the Bolla trial looked atpatients with locally advanced disease, ie, disease that has spread through theprostate capsule but not into other areas of the body such as thebone or liver), when to begin hormonal therapy relative to radiation, and forhow long to continue the hormonal therapy.
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