预防性脑照射不能改善NSCLC患者生存率

威斯康辛大学医学院放射肿瘤学教授Elizabeth Gore博士在芝加哥胸部肿瘤多学科研讨会上报告称，一项针对治疗后无疾病进展的340例局部晚期非小细胞肺癌(NSCLC)患者的随机对照试验表明，预防性脑照射(PCI)可减少5年脑转移率，但未能改善总生存率。

该试验证实了PCI减少脑转移率的有效性，但该试验因患者入组缓慢而提前结束，未能招募到足够的患者以回答有关PCI是否改善Ⅲ期NSCLC患者总生存率的主要问题。Gore博士说：“我需要强调的是参与临床试验的必要性，尤其对于肺癌患者。尽管肺癌是美国癌症死亡的首要原因，但研究并不充分。”

Elizabeth Gore博士

在该项研究中，所有患者的中位随访时间为24.2个月，生存患者为58.6个月。结果显示，随机接受15次30 Gy PCI患者的5年脑转移率为17.3%，而观察组患者为26.8%，两者差异显著(P=0.009)。但5年生存率(26.1% vs. 24.6%)或无病生存率(18.5% vs. 14.9%)均未见显著组间差异。在治疗失败的患者中，10%的PCI组患者和23%的观察组患者首次出现脑转移(BM)。PCI组和观察组BM是首次转移的唯一部位的患者比例分别为9.1%和21.5%。

多变量分析显示，PCI与BM减少显著相关，而非鳞癌组织学特征与BM风险增加相关。在该项试验中，根据组织学特征进行总脑转移率分组分析的可信度不够。

研究者指出，脑转移对肺癌患者生活质量影响较大，在PCI成为标准治疗之前，需要进一步确定哪些患者在生存率方面受益更大。

该研讨会由美国临床肿瘤学会(ASCO)、美国放射肿瘤学会(ASRO)、国际肺癌研究协会(IASLC)和芝加哥大学联合主办。Gore博士及其同事无利益冲突披露。

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By: MIRIAM E. TUCKER, Oncology Practice

Prophylactic cranial irradiation reduced the 5-year rate of brain metastases, but did not improve overall survival in a randomized trial that evaluated 340 patients without disease progression following potentially curative treatment for locally advanced non–small cell lung cancer.

The findings provide important confirmatory information regarding the effectiveness of prophylactic cranial irradiation (PCI) in decreasing the rate of brain failures, Dr. Elizabeth Gore said in a press briefing from the Chicago Multidisciplinary Symposium in Thoracic Oncology.

The trial closed early because of slow patient accrual, however, and did not enroll enough patients to answer the primary question: whether PCI improves overall survival in patients with stage III NSCLC.

"I’d like to emphasize the need for participation in clinical trials. This is particularly important in lung cancer, which is understudied" despite its being the leading cause of cancer death in the United States, said Dr. Gore, professor of radiation oncology at the Medical College of Wisconsin, Milwaukee.

Over a median follow-up of 24.2 months for all patients and 58.6 months for living patients, the 5-year rates of brain metastases were 17.3% for those randomized to receive PCI delivered to 30 Gy in 15 fractions, compared with 26.8% for patients randomized to observation. That difference was statistically significant (P = .009).

However, there were no significant differences in the 5-year rates of survival, (26.1% for PCI and 24.6% for observation), or disease-free survival (18.5% and 14.9%, respectively).

Of the patients with treatment failures, 10% of those receiving PCI and 23% in the observation group experienced failure in the brain initially. Brain metastases (BM) were the only component of first failure in 9.1% and 21.5% of patients with and without PCI, respectively.

On multivariate analysis, PCI was significantly associated with decreased BM, whereas nonsquamous histology was associated with an increased risk of BM. The overall rate of BM in this trial was insufficient for reliable subset analyses by histology, Dr. Gore noted.

"Brain metastasis has a profound impact on patients with lung cancer in terms of quality of life. We need more information to determine which patients are most likely to derive a survival benefit from prophylactic cranial irradiation before this can become a part of standard management," she said.

The Chicago Multidisciplinary Symposium in Thoracic Oncology is sponsored by the American Society of Clinical Oncology, the American Society for Radiation Oncology, the International Association for the Study of Lung Cancer, and the University of Chicago.

Dr. Gore and her associates reported no financial disclosures.

Prophylactic Cranial Irradiation Fails to Improve NSCLC Survival