服用抗凝血劑組的4年時遠端轉移比率低於未服用抗凝血劑組(1% vs 5%；P= .0248)。Choe博士表示，抗凝血劑可能會抑制腫瘤的擴散能力，這些結果可能為此假設提供臨床前證據。
Choe博士與 Zacharski醫師皆宣告沒有相關財務關係。
美國放射腫瘤協會(ASTRO)第51屆年會：摘要2269。發表於2009年11月2日。
Anticoagulants May Aid Biochemical Control in Prostate Cancer
By Nick Mulcahy
Medscape Medical News
November 5, 2009 (Chicago, Illinois) — Anticoagulants are indicated for the treatment of cardiovascular disease but might have a role to play in prostate cancer.
Anticoagulants, including aspirin, warfarin, and clopidogrel, were associated with improved biochemical control of localized prostate cancer in men treated with radiation therapy, according to a new retrospective study of 662 men.
The potential benefit is most pronounced in patients with high-risk localized disease, according to the study's lead author, who presented a poster here at the American Society for Radiation Oncology 51st Annual Meeting.
The current study looked only at men with prostate cancer treated with radiation, not with surgery, explained Kevin S. Choe, MD, PhD, from the University of Chicago Pritzker School of Medicine in Illinois.
The benefit seen in men who undergo radiotherapy while taking anticoagulants likely stems from an "interaction" between the radiation and the drugs, reported Dr. Choe.
At 4 years, biochemical control, or the absence of biochemical relapse as measured by prostate-specific antigen testing, was statistically significantly better in the group of prostate cancer radiotherapy patients receiving anticoagulants than in the group not receiving the blood-thinning therapy (91% vs 78%; P?= .0002).
"We need more data before recommending that men undergoing radiotherapy consider taking anticoagulants," said Dr. Choe. However, the young investigator, who is a resident in radiation oncology at the University of Chicago, also put a positive spin on the results. "Those men with localized prostate cancer who already are on anticoagulants for cardiovascular disease may receive additional benefit when they undergo radiotherapy."
It would need to be planned out very carefully.
The current study was an outgrowth of another study in these same patients, in which Dr. Choe and colleagues investigated rectal bleeding. Prostate cancer patients treated with radiotherapy while taking anticoagulants had a significantly higher risk for this bleeding than patients not taking anticoagulants, he said.
Given this complication, if anticoagulants were ever to be recommended for use in these men, "it would need to be planned out very carefully," said Dr. Choe
Subgroup Analysis: Benefit Only Significant in High-Risk Men
Preclinical studies have indicated that anticoagulants have antineoplastic properties, said Dr. Choe. However, numerous phase?3 randomized studies in a variety of cancer patients, including those with prostate cancer, have failed to show that anticoagulants, as a group, provide therapeutic benefit. Those studies were in patients with advanced disease, said Dr. Choe; the new study is the first in men with localized prostate cancer.
The study cohort consisted of 662 patients with prostate cancer who were treated with radiotherapy at the University of Chicago from 1988 to 2005. Of these men, 243 were receiving warfarin, clopidogrel, and/or aspirin. Most of the men were receiving aspirin alone (n?= 161) or warfarin alone (n?= 42).
The men were treated with seed implants and/or external-beam radiation. The type of radiation received did not influence biochemical control outcomes, said Dr. Choe. About half the men also received short-term androgen-deprivation therapy.
Among the 243 patients, risk was low in 38%, intermediate in 38%, and high in 25%, according to National Comprehensive Cancer Network criteria.
In a subgroup analysis, the improvement in biochemical control was apparent among low- and intermediate-risk men taking anticoagulants, compared with the respective risk groups of men not taking the drugs.
However, biochemical control was only statistically significant in the high-risk men (n?= 165). In that subgroup, the men taking anticoagulants (n?= 52) had a 4-year rate of freedom from biochemical recurrence (i.e., biochemical control) of 82.4%, compared with 57.6% of those not taking anticoagulants (n?= 113; P?= .0007).
The benefit of biochemical control appears to be most pronounced in men with localized high-risk disease.
"The benefit of biochemical control appears to be most pronounced in men with localized high-risk disease," said Dr. Choe.
Anticoagulants had another benefit in the study: the drugs were associated with a reduced rate of metastasis.
The distant metastasis rate at 4 years was lower in the group taking anticoagulants than in the group not taking anticoagulants (1% vs 5%; P?= .0248). "Anticoagulants may inhibit a tumor's ability to spread," said Dr. Choe, adding that "mounting preclinical evidence" supports this hypothesis.
Dr. Choe has disclosed no relevant financial relationships.
American Society for Radiation Oncology (ASTRO) 51st Annual Meeting: Abstract 2269. Presented November 2, 2009.
