Smith Benjamin D, Haffty Bruce G, Buchholz Thomas A, Smith Grace L, Galusha Deron H, Bekelman Justin E, Gross Cary P
Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, USA.
J Natl Cancer Inst. 2006 Sep 20;98(18):1302-10. doi: 10.1093/jnci/djj359.
For women with ductal carcinoma in situ (DCIS), radiation therapy after conservative surgery lowers the risk of recurrence. However, emerging evidence suggests that radiation therapy confers only a marginal absolute benefit for older women with DCIS. In a cohort of older women with DCIS, we sought to determine whether radiation therapy was associated with a clinically significant benefit.
Using the Surveillance, Epidemiology, and End Results (SEER)-Medicare database from January 1, 1992, through December 31, 1999, we identified 3409 women aged 66 years or older treated with conservative surgery for DCIS. A proportional hazards model tested whether radiation therapy was associated with a lower risk of a combined outcome, defined as a subsequent ipsilateral in situ or invasive breast cancer reported by SEER and/or a subsequent mastectomy reported by Medicare claims. The 5-year event risk was determined for patients without and with high-risk features, which were defined as at least one of the following: age 66-69 years, tumor larger than 2.5 cm, comedo histology, and/or high grade. All statistical tests were two-sided.
Radiation therapy was associated with a lower risk for each component of the combined outcome (hazard ratio = 0.32, 95% confidence interval [CI] = 0.24 to 0.44). For high-risk patients, the 5-year event risk was 13.6% without radiation therapy versus 3.8% with radiation therapy (difference = 9.8%, 95% CI = 6.5 to 13.2; P<.001). For low-risk patients, the 5-year event risk was 8.2% without radiation therapy versus 1.0% with radiation therapy (difference = 7.2%, 95% CI = 3.6 to 10.9; P<.001). Among healthy women aged 66-79 years, the number needed to treat with radiation therapy to prevent one event in 5 years was 11 for high-risk patients and 15-16 for low-risk patients.
For older women with DCIS, radiation therapy appears to confer a substantial benefit that remains meaningful even among low-risk patients.
对于导管原位癌（DCIS）女性患者，保乳手术后进行放射治疗可降低复发风险。然而，新出现的证据表明，放射治疗对老年DCIS女性患者仅带来边际绝对获益。在一组老年DCIS女性患者中，我们试图确定放射治疗是否具有临床显著获益。
利用1992年1月1日至1999年12月31日的监测、流行病学和最终结果（SEER）-医疗保险数据库，我们识别出3409名年龄在66岁及以上因DCIS接受保乳手术的女性。一个比例风险模型测试了放射治疗是否与较低的联合结局风险相关，联合结局定义为SEER报告的后续同侧原位或浸润性乳腺癌和/或医疗保险理赔报告的后续乳房切除术。确定了无高危特征和有高危特征患者的5年事件风险，高危特征定义为以下至少一项：年龄66 - 69岁、肿瘤大于2.5 cm、粉刺样组织学和/或高级别。所有统计检验均为双侧检验。
放射治疗与联合结局的各组成部分风险较低相关（风险比 = 0.32，95%置信区间[CI] = 0.24至0.44）。对于高危患者，未进行放射治疗的5年事件风险为13.6%，而进行放射治疗为3.8%（差异 = 9.8%，95%CI = 6.5至13.2；P <.001）。对于低危患者，未进行放射治疗的5年事件风险为8.2%，而进行放射治疗为1.0%（差异 = 7.2%，95%CI = 3.6至10.9；P <.001）。在66 - 79岁的健康女性中，高危患者5年内预防1例事件所需的放射治疗人数为11人，低危患者为15 - 16人。
对于老年DCIS女性患者，放射治疗似乎带来了显著获益，即使在低危患者中也仍然有意义。
