*Department of Radiation Oncology, †Department of Radiology, and ‡Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
J Thorac Oncol. 2015 Nov;10(11):1601-7. doi: 10.1097/JTO.0000000000000648.
The role of stereotactic body radiation therapy (SBRT) in patients with metastatic lung cancer harboring epidermal growth factor receptor (EGFR) mutations is not defined. We evaluated the pattern of failure in patients receiving tyrosine kinase inhibitor (TKI) therapy to identify candidates for consolidation SBRT.
Computed tomography scans were reviewed in a cohort of EGFR-mutant patients enrolled on prospective TKI trials. Initial progression in sites of original disease (primary/metastatic) or new sites was classified as original site failure (OF) or distant site failure (DF), respectively. Simultaneous OF/DF was labeled ODF. Disease characteristics were analyzed for associations with patterns of failure using actuarial competing risks methodology.
Complete serial imaging was available in 49 patients with measurable disease. Median time to any progression was 8.3 months. The majority failed initially in original disease sites with OF, ODF, and DF frequencies being 47.0%, 32.6%, and 20.4%, respectively. Primary tumor size was the most significant predictor of OF in univariate and multivariate analysis (p = 0.004). Median time to progression was 3 months shorter in patients with OF compared with DF. Ten patients (20%) were retroactively classified as consolidation SBRT candidates based on the extent of disease at time of best response to TKI therapy, and in seven of these, initial progression occurred in original tumor sites.
Initial progression of TKI-treated cancers occurred predominantly in original disease sites. Consolidation SBRT was judged feasible in a subset of patients following maximum TKI response and may have prevented oligoprogression in most of these. In addition, we hypothesize that consolidation SBRT for residual disease could delay subsequent metastatic reseeding.
立体定向体部放射治疗（SBRT）在携带表皮生长因子受体（EGFR）突变的转移性肺癌患者中的作用尚未明确。我们评估了接受酪氨酸激酶抑制剂（TKI）治疗的患者的失败模式，以确定巩固性 SBRT 的候选者。
对前瞻性 TKI 试验中入组的一组 EGFR 突变患者的计算机断层扫描进行了回顾性分析。初始时，原始疾病（原发性/转移性）部位或新部位的进展分别被归类为原始部位失败（OF）或远处部位失败（DF）。同时发生 OF/DF 被标记为 ODF。使用生存竞争风险方法分析疾病特征与失败模式之间的关系。
49 例有可测量疾病的患者提供了完整的连续影像学资料。任何进展的中位时间为 8.3 个月。大多数患者最初在原始疾病部位失败，OF、ODF 和 DF 的发生率分别为 47.0%、32.6%和 20.4%。在单因素和多因素分析中，原发肿瘤大小是 OF 的最显著预测因素（p=0.004）。与 DF 相比，OF 患者的中位进展时间缩短了 3 个月。根据 TKI 治疗最佳反应时的疾病程度，10 例患者（20%）被追溯性地归类为巩固性 SBRT 候选者，其中 7 例患者的初始进展发生在原始肿瘤部位。
TKI 治疗的癌症最初进展主要发生在原始疾病部位。在大多数患者中，最大 TKI 反应后，对巩固性 SBRT 的评估是可行的，并且在这些患者中，大多数可能已经预防了寡进展。此外，我们假设对残留疾病进行巩固性 SBRT 可能会延迟随后的转移性再播种。
