Sphincter preservation, crucial for patients traditionally facing abdominoperineal resection, was advanced by neoadjuvant chemoradiotherapy and intersphincteric resection. T4 lower rectal cancer with levator ani muscle infiltration was a contraindication for intersphincteric resection, with most debates on intersphincteric resection indications focusing on the T3 stage.To evaluate oncological outcomes in patients with locally advanced distal rectal cancer, located within 5 cm from the anal verge, who underwent preoperative chemoradiotherapy followed by intersphincteric resection or abdominoperineal resection, with a focus on ypT3 very low rectal cancers that were technically feasible for intersphincteric resection without evidence of levator ani or external sphincter muscle invasion intraoperatively.A retrospective analysis of prospectively collected data.Conducted at 2 colorectal surgery referral centers.The study included 381 patients with ypT3 low rectal cancer who underwent chemoradiotherapy between 2010 and 2021.The main outcome measures were 5-year disease-free survival, 5-year overall survival, circumferential resection margin status, and complications.The 5-year disease-free survival rates were 63.4% for intersphincteric resection and 63.8% for abdominoperineal resection ( p = 0.806), with 5-year overall survival rates at 78.8% for intersphincteric resection and 67.5% for abdominoperineal resection ( p = 0.103). There were no significant differences in 5-year local recurrence or metastasis rates. Circumferential resection margin involvement was low in both groups: 1.9% (5/258) for intersphincteric resection and 4.9% (6/123) for abdominoperineal resection ( p = 0.202). Distal margin involvement was minimal in intersphincteric resection at 0.8% (2/258). Abdominoperineal resection had higher wound infection rates at 15.4% compared to 0.7% in intersphincteric resection ( p < 0.001) and a longer median postoperative hospital stay (10.0 vs 7.0 days for intersphincteric resection, p < 0.001). In abdominoperineal resection cases, primary closure was used for reconstruction, with pelvic peritoneum closure in 4 instances. No significant difference in perineal wound infection rates was observed between those with and without pelvic peritoneum closure ( p = 0.495). Subgroup analysis of intersphincteric resection with handsewn anastomoses showed no significant differences in 5-year disease-free survival (53.8% vs 63.8%, p = 0.068), overall survival (74.5% vs 67.5%, p = 0.313), or local recurrence rates (20.2% vs 21.7%, p = 0.877) compared to abdominoperineal resection.The retrospective design introduced potential selection bias. Procedures were conducted by highly skilled surgeons, which may limit the generalizability of the findings. The study lacked assessment of certain oncological surgical quality control indicators and long-term functional outcomes.For patients with ypT3 low rectal cancer after chemoradiotherapy, intersphincteric resection is safe and oncologically comparable to abdominoperineal resection when negative margins can be achieved. See Video Abstract.ANTECEDENTES:La preservación del esfínter, crucial para los pacientes que tradicionalmente se enfrentan a una resección abdominoperineal, ha sido impulsado gracias a la quimiorradioterapia neoadyuvante y la resección intersfinteriana. El cáncer rectal inferior T4 con infiltración del músculo elevador del ano ha sido una contraindicación para la resección intersfinteriana, y la mayoría de los debates se centran sobre las indicaciones de la resección intersfinteriana en el estadio T3.OBJETIVO:Evaluar los resultados oncológicos en pacientes con cáncer rectal distal localmente avanzado, localizados a menos de 5 cm del borde anal, que se sometidos a quimiorradioterapia preoperatoria seguida de resección intersfinteriana o resección abdominoperineal, centrándose en los cánceres rectales muy bajos ypT3 que eran técnicamente viables para la resección intersfinteriana sin evidencia de invasión del músculo elevador del ano o del esfínter externo durante la intervención quirúrgica.DISEÑO:Análisis retrospectivo de datos recogidos prospectivamente.ENTORNO:Realizado en dos centros de referencia en cirugía colorrectal.PACIENTES:El estudio incluyó a 381 pacientes con cáncer rectal bajo ypT3 tras quimiorradioterapia, entre los años 2010 y 2021.PRINCIPALES MEDIDAS DE RESULTADO:Supervivencia libre de enfermedad a cinco años, supervivencia global a cinco años, estado del margen de resección circunferencial y complicaciones.RESULTADOS:Las tasas de supervivencia libre de enfermedad a 5 años fueron del 63,4 % para la resección intersfinteriana y del 63,8 % para la resección abdominoperineal ( p = 0,806), con tasas de supervivencia global a 5 años del 78,8 % para la resección intersfinteriana y del 67,5 % para la resección abdominoperineal ( p = 0,103). No hubo diferencias significativas en las tasas de recurrencia local o metástasis a los 5 años. La afectación del margen de resección circunferencial fue baja en ambos grupos: 1,9 % (5/258) para la resección intersfinteriana y 4,9 % (6/123) para la resección abdominoperineal ( p = 0,202). La afectación del margen distal fue mínima en la resección intersfinteriana, con un 0,8 % (2/258). La resección abdominoperineal presentó tasas más elevadas de infección de la herida con un 15,4 %, en comparación con el 0,7 % en la resección intersfinteriana ( p < 0,001), asi como una mediana de estancia hospitalaria postoperatoria más prolongada (10,0 días frente a 7,0 días para la resección intersfinteriana, p < 0,001). En los casos de resección abdominoperineal, se utilizó el cierre primario para la reconstrucción, con cierre del peritoneo pélvico en 4 casos. No se observaron diferencias significativas en las tasas de infección de la herida perineal entre los pacientes con y sin cierre del peritoneo pélvico ( p = 0,495). El análisis de subgrupos de la resección intersfinteriana con anastomosis hechas con suturas a mano no mostraron diferencias significativas en la supervivencia libre de enfermedad a 5 años (53,8 % frente a 63,8 %, p = 0,068), la supervivencia global (74,5 % frente a 67,5 %, p = 0,313) o las tasas de recidiva local (20,2 % frente a 21,7 %, p = 0,877) en comparación con la resección abdominoperineal.LIMITACIONES:El diseño retrospectivo introdujo un posible sesgo de selección. Las intervenciones fueron realizadas por cirujanos altamente cualificados, lo que puede limitar la generalización de los resultados. El estudio no evaluó determinados indicadores de control de calidad quirúrgica oncológica ni los resultados funcionales a largo plazo.CONCLUSIONES:En pacientes con cáncer rectal bajo ypT3 tras quimiorradioterapia, la ISR es segura y oncológicamente comparable a la resección abdominoperineal cuando se pueden lograr márgenes negativos. (Traducción-Dr Osvaldo Gauto).Copyright © The ASCRS 2025.

Intersphincteric resection has become a widely used treatment for patients with rectal cancer. However, the detailed anatomy of the anal canal related to this procedure has remained unclear.The purpose of this study was to clarify the detailed anatomy of the anal canal.This is a descriptive study.Histologic evaluations of paraffin-embedded tissue specimens were conducted at a tertiary referral hospital.Tissue specimens were obtained from cadavers of 5 adults and from 13 patients who underwent abdominoperineal resection for rectal cancer.Sagittal sections from 9 circumferential portions of the cadaveric anal canal (histologic staining) and 3 circumferential portions from patients were studied (immunohistochemistry for smooth and skeletal muscle fibers).Longitudinal fibers between the internal and external anal sphincters consisted primarily of smooth muscle fibers that continued from the longitudinal muscle of the rectum. The levator ani muscle attached directly to the lateral surface of the longitudinal smooth muscle of the rectum. The length of the attachment was longer in the anterolateral portion and shorter in the posterior portion of the anal canal. In the lateral and posterior portions, the levator ani muscle partially overlapped the external anal sphincter; however, there was less overlap in the anterolateral portion. In the posterior portion, thick smooth muscle was present on the surface of the levator ani muscle and it continued to the longitudinal muscle of the rectum.We observed only limited portions in some surgical specimens because of obstruction by tumors.The levator ani muscle attaches directly to the longitudinal muscle of the rectum. The spatial relationship between the smooth and skeletal muscles differed in different portions of the anal canal. For intersphincteric resection, dissection must be performed between the longitudinal muscle of the rectum and the levator ani muscle/external anal sphincter, and the appropriate surgical lines must be selected based on the specific structural characteristics of each portion.

Anastomotic leakage (AL) is a major complication of colorectal surgery that can lead to abdominal infection and systemic inflammatory response. Meanwhile, the microbiota and immune microenvironment at the anastomosis are closely related to the formation of AL. Presently, a considerable volume of research is directed toward investigating the colorectal microenvironment in AL. These studies offer a robust foundation for probing etiological factors contributing to the AL. This is the first review to comprehensively depict the bidirectional effects of intestinal immunity and microbiota on anastomotic healing. Furthermore, this study also elaborates on the association between the clinical risk factors and micro-mechanisms of AL, and provides a novel perspective for its early diagnosis.

&lt;b&gt;<i>Backgrounds/Aims:</i>&lt;/b&gt; On the basis of acceptable oncologic results, ultralow anterior resection (ULAR) and colo-anal anastomosis plus hand-sewn coloanal anastomosis have been performed for treating very low-lying rectal cancer. However, many patients experience bowel dysfunction after ULAR. Studies have provided inadequate data on bowel dysfunctions and only a few functional studies have focused on low rectal cancer. Therefore, we aimed to elucidate the severity of bowel dysfunction after ULAR in a single-surgeon cohort. &lt;b&gt;<i>Methods:</i>&lt;/b&gt; In this prospective observational study, we analyzed data of 203 patients who underwent sphincter-preserving surgery for low-lying rectal cancer (tumor located within 5 cm from the anus) between January 2011 and December 2014. During routine follow-up, examinations (3–6 months interval) after ileostomy closure, patients were asked about their bowel functions based on the Wexner incontinence and LAR syndrome (LARS) scores. Patients were divided into 2 groups: LAR group (LAR with double-stapled anastomosis) and ULAR group (ULAR with coloanal anastomosis), and functional scores were compared between 6 and 36 months. Seven risk factors for major LARS were analyzed. &lt;b&gt;<i>Results:</i>&lt;/b&gt; At 36 months after surgery, 94.2 and 70.6% of patients in the ULAR group still had moderate to severe incontinence and major LARS respectively. Fecal incontinence improved significantly over time (ULAR group, 14.4 vs. 7.2, <i>p</i> = 0.045; LAR group, 13.9 vs. 5.4, <i>p</i> &amp;#x3c; 0.05). However, improvement in LARS over time was observed in the LAR group only (26.5 vs. 19.7, <i>p</i> = 0.045). In the ULAR group, the difference did not reach a statistical significance (33.6 vs. 26.0, <i>p</i> = 0.10). Major LARS and moderate incontinence were significantly higher in the ULAR group than in the LAR group (70.6 vs. 47.6%, <i>p</i> = 0.001; 82.4 vs. 32.0%, <i>p</i> = 0.012 respectively). Among the 7 factors evaluated in multivariable analysis, old age (&amp;#x3e; 70), male sex, ULAR per se, and chemoradiation therapy were found to be meaningful risk factors for major LARS. &lt;b&gt;<i>Conclusion:</i>&lt;/b&gt; In patients with low rectal cancers undergoing ULAR plus coloanal anastomosis, bowel dysfunctions were severe. Bowel dysfunctions improved over time, but most patients still experienced major bowel dysfunctions even 36 months after surgery. Risk factors for bowel dysfunctions were old age, male sex, adjuvant chemoradiation therapy, and ULAR. Therefore, ULAR should be performed in carefully selected patients with low-lying rectal cancer.

According to international guidelines, the standard treatment for stage T2-T3ab, N0, M0 rectal cancer is total mesorectal excision (TME), but it is associated with high morbidity and quality of life disorders.To analyze locoregional recurrence (LR) after a follow-up of 2 years, applying a 1-sided noninferiority margin of 10%, and to assess distant recurrence (DR), overall survival (OS), and disease-free survival (DFS).This was a multicenter, prospective, open-label, noninferiority, phase 3 randomized clinical trial comparing TME (TME group) with chemoradiotherapy followed by local excision with transanal endoscopic microsurgery (CRT-TEM group). This study involved 17 hospitals in Spain. Eligibility criteria included patients with rectal adenocarcinoma located lower than 10 cm from the anal verge; stage T2-T3ab N0, M0; tumor size less than or equal to 4 cm in diameter; and American Society of Anesthesiologists stage III or less with no metastasis. Sample size was calculated with a 1-sided significance level of 2.5% and a power of 80%, assuming a nonrecurrence rate of 95% in each arm and a possible loss of 15%. Randomization was performed with a 1:1 allocation ratio. Data were analyzed from July 2010 to October 2021.The 2 treatment groups were CRT-TEM and TME.The main study outcome was LR.From July 2010 to October 2021, 173 patients (median [IQR] age, 67 [59-75] years; 116 male [67.1%]) were included (CRT-TEM, n = 86; TME, n = 87). In the 5-year modified intention-to-treat analysis, LR was 6.2% (5 of 81 patients) in the TME group and 7.4% (6 of 81 patients) in the CRT-TEM group (difference, -1.23%; 95% CI, 6.51% to -8.98%). DR was 17.3% (14 of 81 patients) in the TME group and 12.3% (10 of 81 patients) in the CRT-TEM group (difference, 4.94%; 95% CI, 15.85% to -5.98%). OS was 85.2% (69 of 81 patients) in the TME group and 82.7% (67 of 81 patients) in the CRT-TEM group (difference, 2.47%; 95% CI, 0.38%-1.78%). DFS in both groups was 88.9% (72 of 81), with a 95% CI of 9.68 to -9.68.Results of this randomized clinical trial reveal that CRT-TEM achieved noninferior results compared with standard TME treatment in terms of LR and similar results in terms of DR, OS, and DFS. CRT-TEM appears to be a suitable treatment option for patients with T2-T3ab, N0, M0 rectal cancer.ClinicalTrials.gov Identifier: NCT01308190.