Background

Rectal cancer patients with microsatellite instability (MSI-H) are candidates for immunotherapy. However, there is little evidence on its effect on overall survival (OS).

Methods

Retrospective analysis of stage II–IV rectal adenocarcinoma patients in the National Cancer Database (NCDB) between 2010 and 2019. Propensity score matching was adjusted for baseline and treatment confounders. The cohort was divided into patients who received immunotherapy and matched controls. The primary outcome was OS.

Results

5175/206,615 (2.5%) patients with rectal adenocarcinoma underwent immunotherapy. These patients were younger (58 vs 62 years; p < 0.001), more often male (64.4% vs 61.7%; p < 0.001), were more likely to have private insurance (50.8% vs 43.4%; p < 0.001), more metastatic disease at presentation (clinical TNM stage IV–80.8% vs 23.3%; p < 0.001), presented with larger tumors (median: 5 cm vs. 4.2 cm; p < 0.001) and less often underwent surgery (33.7% vs. 69.9%; p < 0.001), radiation therapy (21.5% vs 57.4%; p < 0.001), and standard chemotherapy (38.1% vs 61%; p < 0.001) than controls. After matching, 488 patients were in each group. OS was significantly shorter in the immunotherapy group (mean survival: 56.4 months (95% CI: –53.03–59.86)) compared to controls (mean survival: 70.5 months (95% CI: –66.15–74.92) (p = 0.004)). Cox regression analysis of factors associated with OS demonstrated that immunotherapy was associated with increased mortality (HR 2.16; 95% CI: 2.09–2.24; p < 0.001). After clinical staging stratification, immunotherapy was associated with improved OS in stage IV (HR 0.91, 95% CI: 0.88–0.95; p < 0.001) but lower survival in stage II (HR 2.38; 95% CI: 2.05–2.77; p < 0.001) and stage III (HR 2.43; 95% CI: 2.18–2.7; p < 0.001) patients.

Conclusion

Immunotherapy showed modest increase in OS in stage IV metastatic rectal cancer. OS was significantly lower in stage II–III disease treated with immunotherapy.

中文翻译：

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直肠癌患者的免疫治疗——国家癌症数据库的倾向评分匹配分析

背景

具有微卫星不稳定性（MSI-H）的直肠癌患者是免疫治疗的候选者。然而，几乎没有证据表明其对总生存期 (OS) 的影响。

方法

对 2010 年至 2019 年国家癌症数据库 (NCDB) 中 II-IV 期直肠腺癌患者的回顾性分析。倾向评分匹配针对基线和治疗混杂因素进行了调整。该队列被分为接受免疫治疗的患者和匹配的对照组。主要结局是 OS。

结果

5175/206,615 (2.5%) 直肠腺癌患者接受了免疫治疗。这些患者更年轻（58 岁 vs 62 岁；p  < 0.001），男性较多（64.4% vs 61.7%；p  < 0.001），更有可能拥有私人保险（50.8% vs 43.4%；p  < 0.001），更多就诊时存在转移性疾病（临床 TNM IV 期–80.8% vs 23.3%；p  < 0.001），肿瘤较大（中位数：5 cm vs. 4.2 cm；p  < 0.001），且较少接受手术（33.7% vs. 69.9） %；p  < 0.001）、放射治疗（21.5% vs 57.4%；p  < 0.001）和标准化疗（38.1% vs 61%；p  < 0.001）优于对照组。匹配后，每组各有488名患者。与对照组相比，免疫治疗组的 OS 显着缩短（平均生存期：56.4 个月（95% CI：–53.03–59.86））（平均生存期：70.5 个月（95% CI：–66.15–74.92）（p  = 0.004）） 。与 OS 相关因素的 Cox 回归分析表明，免疫治疗与死亡率增加相关（HR 2.16；95% CI：2.09–2.24；p  < 0.001）。临床分期分层后，免疫治疗与 IV 期 OS 改善相关（HR 0.91，95% CI：0.88–0.95；p  < 0.001），但 II 期生存率较低（HR 2.38；95% CI：2.05–2.77；p  < 0.001）。 0.001）和 III 期（HR 2.43；95% CI：2.18–2.7；p  < 0.001）患者。

结论

免疫疗法显示 IV 期转移性直肠癌的 OS 略有增加。使用免疫疗法治疗的 II-III 期疾病的 OS 显着降低。