Purpose

To evaluate the predictive implications and prognosis of mucinous adenocarcinoma (MAC) in locally advanced rectal cancer (LARC) with intensified neoadjuvant treatment.

Methods

Individual patient data of LARC patients from 3 prospective clinical trials was analyzed. Neoadjuvant treatment regimens comprised chemoradiotherapy (CRT) with fluorouracil (5-FU) or mFOLFOX6, neoadjuvant chemotherapy alone with mFOLFOX6 or mFOLFOXIRI. The postoperative pathological result, local recurrence and disease-free survival (DFS) were retrospectively analyzed in patients with MAC and adenocarcinoma (AC) with neoadjuvant treatment.

Results

Totally, 743 patients were recruited, with 620 patients eligible for analysis. Fifty-three (8.5%) patients were MAC. The pathological complete response (pCR) rate and tumor downstaging rate (ypStage 0-I) between MAC and AC patients was 7.5% vs. 22.0% (P = .01) and 20.8% vs. 48.7% (P < .001), respectively. Among patients receiving preoperative CRT with 5FU or mFOLFOX6, the pCR rate and tumor downstaging rate between MAC and AC patients was 11.1% vs. 27.3% (P = .03) and 23.7% vs. 52.6% (P = .001), respectively. Regarding neoadjuvant chemotherapy alone with mFOLFOX6 or mFOLFOXIRI, the pCR rate and tumor downstaging rate was 0 vs.13.2% (P = .11) and 11.8% vs. 42.5% (P = .03) between MAC and AC group, respectively. With the median follow-up time of 38.9 months, the 3-year DFS and 3-year locoregional recurrence rate was 58.4% vs. 77.6% (P = .02) and 26.0% vs. 5.7% (P = .001) in the MAC and AC group, respectively. MAC (hazard ratio [HR] 1.85, 95% confidence interval [CI], 1.15-2.98), PNI (HR 3.23, 95% CI, 1.85-5.72) and LVI (HR 2.04, 95% CI, 1.02-4.08) were independent prognosis factors and were associated with worse DFS.

Conclusions

Patients with MAC of the rectum are associated with a lower pCR rate and tumor downstaging rate, higher incidence of local recurrence, and poorer DFS with neoadjuvant treatment.

中文翻译：

---

粘液性腺癌预测局部晚期直肠癌患者的不良反应和预后：来自 3 项前瞻性研究的个体参与者数据的汇总分析

目的

评估黏液腺癌 (MAC) 在局部晚期直肠癌 (LARC) 中强化新辅助治疗的预测意义和预后。

方法

分析了来自 3 项前瞻性临床试验的 LARC 患者的个体患者数据。新辅助治疗方案包括使用氟尿嘧啶 (5-FU) 或 mFOLFOX6 的放化疗 (CRT)、使用 mFOLFOX6 或 mFOLFOXIRI 的单独新辅助化疗。回顾性分析新辅助治疗的MAC合并腺癌（AC）患者的术后病理结果、局部复发和无病生存期（DFS）。

结果

总共招募了 743 名患者，其中 620 名患者符合分析条件。53 名 (8.5%) 患者为 MAC。MAC 和 AC 患者的病理完全缓解 (pCR) 率和肿瘤降期率 (ypStage 0-I) 分别为 7.5% vs. 22.0% ( P  = .01) 和 20.8% vs. 48.7% ( P < .001)，分别。在接受术前 CRT 和 5FU 或 mFOLFOX6 的患者中，MAC 和 AC 患者的 pCR 率和肿瘤降期率分别为 11.1% 和 27.3% ( P  = .03) 和 23.7% 和 52.6% ( P  = .001) . 对于单独使用 mFOLFOX6 或 mFOLFOXIRI 的新辅助化疗，pCR 率和肿瘤降期率分别为 0 对 13.2% ( P  = .11) 和 11.8% 对 42.5% ( P = .03) 分别在 MAC 和 AC 组之间。中位随访时间为 38.9 个月，3 年 DFS 和 3 年局部复发率分别为 58.4% 和 77.6% ( P  = .02) 和 26.0% 和 5.7% ( P  = .001) MAC 组和 AC 组。MAC（风险比 [HR] 1.85, 95% CI, 1.15-2.98）、PNI（HR 3.23, 95% CI, 1.85-5.72）和 LVI（HR 2.04, 95% CI, 1.02-4.08）独立的预后因素，并与较差的 DFS 相关。

结论

直肠 MAC 患者的 pCR 率和肿瘤降期率较低，局部复发率较高，新辅助治疗的 DFS 较差。