State Key Laboratory of Agricultural Microbiology & Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
Department of Radiation Oncology, Hubei Cancer Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430071, People's Republic of China.
J Cancer Res Clin Oncol. 2023 Aug;149(9):6085-6096. doi: 10.1007/s00432-022-04553-6. Epub 2023 Jan 19.
Neo-adjuvant radiotherapy (NART) is a widely used pre-surgery radiotherapy for rectal cancer patients. Although NART is effective in reducing tumor burden before surgery, it may cause dysbiosis of intestinal microbiota. The intestinal microbiota shapes tumor inflammatory environment and influences cancer progression. However, how NART remodels the microbiota and how the microbiota affects therapeutic efficacy has been largely elusive. This study aimed to reveal the details of how NART affects the intestinal microbiota in patients with rectal cancer.
Rectal cancer patients who received NART were recruited into the study, and their healthy family members on the same diet served as controls. Stool samples from five rectal cancer patients (28 in total) and five healthy individuals (16 in total) were collected for intestinal microbiota analysis by 16S rRNA gene amplicon sequencing. Samples from patients were divided into earlier- and later-NART according to the number of NART.
NART did not significantly affect the α diversity of intestinal microbiota. However, the abundance of bacterial genera associated with cancer progression tended to decrease in later-NART patients. More importantly, a variety of oral pathogenic bacteria were enriched in the intestine of later-NART patients. NART also affected functional pathways associated with the microbiota in DNA repair, metabolism, and bacterial infection.
NART significantly altered the microbiota composition and function in rectal cancer patients, and some oral pathogens were found to translocate to the intestine. This is the first report to study the effect of NART on intestinal microbiota in patients with rectal cancer, exploring the importance of intestinal microbiota during the process of NART.
新辅助放疗（NART）是一种广泛应用于直肠癌患者术前的放疗方法。尽管 NART 在术前降低肿瘤负担方面非常有效，但它可能会导致肠道微生物群落失调。肠道微生物群落塑造肿瘤炎症环境并影响癌症进展。然而，NART 如何重塑微生物群，以及微生物群如何影响治疗效果，在很大程度上仍不清楚。本研究旨在揭示 NART 如何影响直肠癌患者肠道微生物群的细节。
招募接受 NART 的直肠癌患者，并招募与其同饮食的健康家庭成员作为对照。从五名直肠癌患者（共 28 名）和五名健康个体（共 16 名）中收集粪便样本，通过 16S rRNA 基因扩增子测序进行肠道微生物组分析。根据 NART 的次数，将患者样本分为早期和晚期 NART。
NART 对肠道微生物群的α多样性没有显著影响。然而，与癌症进展相关的细菌属的丰度在晚期 NART 患者中趋于降低。更重要的是，各种口腔病原菌在晚期 NART 患者的肠道中被富集。NART 还影响与 DNA 修复、代谢和细菌感染相关的微生物功能途径。
NART 显著改变了直肠癌患者的微生物群落组成和功能，并且发现一些口腔病原体已转移到肠道。这是第一项研究 NART 对直肠癌患者肠道微生物群影响的报告，探讨了肠道微生物群在 NART 过程中的重要性。
