Objective To explore risk factors for metachronous tumor lesions after radical resection of rectal cancer (RC). Methods A retrospective study was conducted on 757 RC patients who underwent RC radical surgery at the Sixth Affiliated Hospital, Sun Yat-sen University from October 2012 to June 2018. The patients were divided into early-onset RC group (EO-RC group, ＜50 years old, n=228) and average-onset RC group (AO-RC group, ≥ 50 years old, n=529) based on their age of diagnosis, and were followed up until March 2025. General information, initial colonoscopy, follow-up colonoscopy, and other relevant clinical information were collected from all patients. The risk of developing metachronous tumor lesions was compared between two groups using Kaplan Meier (K-M) risk function; univariate and multivariate Cox proportional hazards models were used to analyze the influencing factors of metachronous tumor lesions after RC radical surgery. Results The median follow-up time was 30 (15, 58) months. The K-M risk function showed that the risk of developing metachronous tumor lesions in the EO-RC group was significantly lower than that in the AO-RC group (P＜0.001). The results of the multivariate Cox proportional hazards model showed that the risk of metachronous tumor lesions after RC surgery in the EO-RC group was 50.8% of that in the AO-RC group (P＜0.001); PIK3CA mutation and synchronous advanced adenoma were independent risk factors for metachronous tumor lesions after RC surgery (HR=2.360, 2.094; P=0.003, P＜0.001). Conclusions RC patients with advanced age, PIK3CA mutations, and synchronous advanced adenomas are prone to developing metachronous tumor lesions after surgery. Patients with EO-RC may not require intensified colonoscopy surveillance postoperatively. However, intensified surveillance strategies should be considered for RC patients harboring PIK3CA mutations or presenting with synchronous advanced adenomas.

Objective:This report presents the initial outcomes of endoscopic intermuscular dissection (EID), a novel technique introduced by our team for the diagnostic resection of early rectal cancer, focusing on the postoperative status of the vertical margins.Methods:On January 26, 2024, a patient with early rectal cancer (cT1-2N0M0) underwent Endoscopic Intermuscular Dissection. The EID procedure consists of six steps: (1) mucosal incision; (2) submucosal dissection; (3) superficial muscular layer incision; (4) intermuscular dissection; (5) complete tumor removal; (6) wound management.Results:The patient was a 70-year-old male with rectal cancer (cT1-2N0M0). The tumor was located on the left anterior wall of the rectum, approximately 9 cm from the anal margin, and measured 20mm in size. The dissection rate was 2.68 mm2/minute, and the total duration of the surgery was 109 minutes. The patient was successfully discharged on the fifth day after surgery. Pathological examination of the post-endoscopic surgery specimen revealed pT1b, with negative vertical margins. Follow-up after more than one month showed good recovery with no complications such as bleeding, perforation, infection, or stricture occurring. Colonoscopy indicated the presence of a granulation tissue suggestive of inflammation.Conclusion:Endoscopic Intermuscular Dissection for the diagnostic resection of early rectal cancer is potentially safe and may achieve negative vertical margins.

Objective:This report presents the initial outcomes of endoscopic intermuscular dissection (EID), a novel technique introduced by our team for the diagnostic resection of early rectal cancer, focusing on the postoperative status of the vertical margins.Methods:On January 26, 2024, a patient with early rectal cancer (cT1-2N0M0) underwent Endoscopic Intermuscular Dissection. The EID procedure consists of six steps: (1) mucosal incision; (2) submucosal dissection; (3) superficial muscular layer incision; (4) intermuscular dissection; (5) complete tumor removal; (6) wound management.Results:The patient was a 70-year-old male with rectal cancer (cT1-2N0M0). The tumor was located on the left anterior wall of the rectum, approximately 9 cm from the anal margin, and measured 20mm in size. The dissection rate was 2.68 mm2/minute, and the total duration of the surgery was 109 minutes. The patient was successfully discharged on the fifth day after surgery. Pathological examination of the post-endoscopic surgery specimen revealed pT1b, with negative vertical margins. Follow-up after more than one month showed good recovery with no complications such as bleeding, perforation, infection, or stricture occurring. Colonoscopy indicated the presence of a granulation tissue suggestive of inflammation.Conclusion:Endoscopic Intermuscular Dissection for the diagnostic resection of early rectal cancer is potentially safe and may achieve negative vertical margins.

Ionizing radiation can induce the death of lymphatic endothelial cells, leading to structural damage, dysfunction, and reduction of lymphatic vessels, which poses a negative impact on radiotherapy. However, it can also induce tumor cells and tumor-infiltrated immune cells to secrete various cytokines and promote tumor-associated lymphangiogenesis, which favors anti-tumor therapy and improve anti-tumor immunity. Studying the changes in lymphatic vessels after ionizing radiation may be a way to explore the synergistic anti-tumor effects of radiotherapy and immunotherapy. This review summarized the morphological changes in lymphatics after ionizing radiation, the molecular mechanisms for the effects of ionizing radiation on lymphatic vessels, and the clinical value of lymphatic changes after ionizing radiation, aiming to provide ideas for the study of the effects of ionizing radiation on lymphatic vessels.