Purpose

We aimed to assess the prognostic value of restaging magnetic resonance imaging (MRI) in rectal cancer after neoadjuvant therapy and compare long-course chemoradiotherapy (LC-CRT) to short-course radiotherapy with delayed surgery (SCRT-delay).

Methods

This retrospective study included 267 patients with locally advanced rectal cancer (LARC) operated on between January 2016 and April 2019, all of whom received either LC-CRT or SCRT-delay in the neoadjuvant setting. The primary outcomes were overall survival (OS) and cancer-specific survival (CSS) based on radiological response assessed using the magnetic resonance tumor regression grade (mrTRG).

Results

In the LC-CRT group, cumulative 1-, 3-, and 5-year OS rates were 94.8%, 86.4%, and 79.0%, while in the SCRT-delay group, they were 83.3%, 68.9%, and 68.9% (P = 0.017). For CSS in the LC-CRT group, cumulative rates were 96.9%, 90.3%, and 85.0%, and in the SCRT-delay group, they were 88.6%, 81.4%, and 81.4% (P = 0.222). There were no significant differences in total histological response rates or local recurrence rates between the treatment groups. The good and moderate response group (mrTRG 1–3) had significantly better cumulative 1-, 3-, and 5-year OS and CSS compared to the poorer response group (mrTRG 4–5) (P = 0.023 for OS and P = 0.048 for CSS).

Conclusion

Unfavorable MRI response is a sign of poor prognosis in LARC. SCRT-delay is comparable to LC-CRT concerning the oncological outcome.

中文翻译：

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磁共振成像对局部晚期直肠癌重新分期的发现

目的

我们的目的是评估新辅助治疗后磁共振成像（MRI）再分期对直肠癌的预后价值，并将长程放化疗（LC-CRT）与短程放疗加延迟手术（SCRT-delay）进行比较。

方法

这项回顾性研究纳入了 2016 年 1 月至 2019 年 4 月期间接受手术的 267 名局部晚期直肠癌 (LARC) 患者，所有患者均在新辅助治疗中接受了 LC-CRT 或 SCRT 延迟治疗。主要结局是基于使用磁共振肿瘤回归等级（mrTRG）评估的放射学反应的总生存期（OS）和癌症特异性生存期（CSS）。

结果

LC-CRT 组的累积 1 年、3 年和 5 年 OS 率分别为 94.8%、86.4% 和 79.0%，而 SCRT 延迟组分别为 83.3%、68.9% 和 68.9% （P  = 0.017）。 LC-CRT 组的 CSS 累积发生率分别为 96.9%、90.3% 和 85.0%，SCRT 延迟组的累积发生率分别为 88.6%、81.4% 和 81.4%（P  = 0.222）。治疗组之间的总组织学缓解率或局部复发率没有显着差异。与较差反应组 (mrTRG 4-5) 相比，良好和中等反应组 (mrTRG 1-3) 的累积 1 年、3 年和 5 年 OS 和 CSS 明显更好（ OS 的P = 0.023， P  = CSS 为 0.048）。

结论

不良 MRI 反应是 LARC 预后不良的标志。就肿瘤学结果而言，SCRT 延迟与 LC-CRT 相当。