Background: Radiation dose escalation for locally advanced pancreatic cancer (LAPC) using stereotactic magnetic resonance (MR)-guided online adaptive radiation therapy (SMART) or computed tomography (CT)-guided moderately hypofractionated ablative radiation therapy (HART) can achieve favorable outcomes although have not previously been compared. Methods: We performed a multi-center retrospective analysis of SMART (50 Gy/5 fractions) vs. HART (75 Gy/25 fractions or 67.5 Gy/15 fractions with concurrent capecitabine) for LAPC. Gray’s test and Cox proportional regression analyses were performed to identify factors associated with local failure (LF) and overall survival (OS). Results: A total of 211 patients (SMART,n= 91; HART,n= 120) were evaluated, and none had surgery. Median follow-up after SMART and HART was 27.0 and 40.0 months, respectively (p< 0.0002). SMART achieved higher gross tumor volume (GTV) coverage and greater hotspots. Two-year LF after SMART and HART was 6.5% and 32.9% (p< 0.001), while two-year OS was 31.0% vs. 35.3% (p= 0.056), respectively. LF was associated with SMART vs. HART (HR 5.389, 95% CI: 1.298–21.975;p= 0.021) and induction mFOLFIRINOX vs. non-mFOLFIRINOX (HR 2.067, 95% CI 1.038–4.052;p= 0.047), while OS was associated with CA19-9 decrease > 40% (HR 0.725, 95% CI 0.515–0.996;p= 0.046) and GTV V120% (HR 1.022, 95% CI 1.006–1.037;p= 0.015). Acute grade > 3 toxicity was similar (3.3% vs. 5.8%;p= 0.390), while late grade > 3 toxicity was less common after SMART (2.2% vs. 9.2%;p= 0.037). Conclusions: Ablative SMART and HART both achieve favorable oncologic outcomes for LAPC with minimal toxicity. We did not observe an OS difference, although technical advantages of SMART might improve target coverage and reduce LF.
背景：对于局部晚期胰腺癌（LAPC），采用立体定向磁共振（MR）引导在线自适应放射治疗（SMART）或计算机断层扫描（CT）引导的中度大分割消融放射治疗（HART）进行剂量递增可获得良好疗效，但此前尚未对这两种方法进行过比较。方法：我们对SMART（50 Gy/5次分割）与HART（75 Gy/25次分割或67.5 Gy/15次分割联合卡培他滨同步治疗）用于LAPC进行了多中心回顾性分析。采用Gray检验和Cox比例风险回归分析来确定与局部失败（LF）和总生存期（OS）相关的因素。结果：共评估了211例患者（SMART组91例；HART组120例），均未接受手术。SMART组和HART组的中位随访时间分别为27.0个月和40.0个月（p < 0.0002）。SMART实现了更高的肿瘤大体体积（GTV）覆盖率和更大的热点区域。SMART组和HART组的两年LF率分别为6.5%和32.9%（p < 0.001），而两年OS率分别为31.0%和35.3%（p = 0.056）。LF与SMART vs. HART（HR 5.389，95% CI：1.298–21.975；p = 0.021）以及诱导mFOLFIRINOX vs. 非mFOLFIRINOX（HR 2.067，95% CI 1.038–4.052；p = 0.047）相关，而OS与CA19-9下降 > 40%（HR 0.725，95% CI 0.515–0.996；p = 0.046）和GTV V120%（HR 1.022，95% CI 1.006–1.037；p = 0.015）相关。急性≥3级毒性反应发生率相似（3.3% vs. 5.8%；p = 0.390），而SMART组晚期≥3级毒性反应较少见（2.2% vs. 9.2%；p = 0.037）。结论：消融性SMART和HART均能为LAPC带来良好的肿瘤学结局且毒性反应轻微。我们未观察到OS差异，但SMART的技术优势可能改善靶区覆盖并降低LF率。
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