Researchers at Fukuoka University Hospital analyzed data from 320 patients who underwent low anterior resection for rectal tumors between 2016 and 2025. Their findings, published in Annals of Gastroenterological Surgery, used a statistical technique called exploratory factor analysis to dissect the two most widely used patient-reported measures of postoperative bowel function: the LARS score and the Cleveland Clinic Florida Fecal Incontinence Score, better known as the Wexner score. What emerged was a three-part structure that the authors say should change how clinicians think about, measure and treat bowel dysfunction after rectal surgery.

The logic behind the study is straightforward but powerful. The LARS score bundles five symptoms into a single number, while the Wexner score focuses mainly on incontinence. Clinicians have long noticed that the two instruments sometimes disagree, giving conflicting impressions of the same patient. The Japanese team suspected that this discordance arises because the scores are actually measuring different underlying dimensions of bowel dysfunction, dimensions that a composite total quietly blends together. To test that idea, they went beneath the total scores and examined the individual symptom items themselves.

First, the researchers mapped how the symptoms correlated with one another. Some pairs were tightly linked: Wexner liquid incontinence and LARS liquid stool incontinence correlated strongly, with a Spearman coefficient of 0.71, and urgency tracked closely with clustering at 0.59. Other symptoms, notably bowel frequency, floated loosely, correlating weakly with nearly everything else. When the team reorganized the correlation matrix using hierarchical clustering, related symptoms visibly grouped together, hinting that the syndrome had natural fault lines running through it.

Formal factor analysis confirmed the hunch. Using maximum likelihood extraction with Quartimin rotation on pooled observations from 6, 12 and 24 months after surgery, the analysis retained three factors that together explained 64.7 percent of the total variance. The first factor gathered the incontinence-related items, including liquid and solid stool incontinence, pad use and lifestyle alteration. The second was defined almost entirely by urgency and clustering, with a smaller contribution from bowel frequency. The third captured gas incontinence from both instruments, pointing to a separate domain of impaired gas control that neither score was designed to isolate on its own.

The real payoff came when the team asked which clinical factors drove each domain. Using multivariable mixed-effects models that accounted for repeated measurements in the same patients over time, they found that the same risk factors did not affect all domains equally. Very low anterior resection, in which the stapled anastomosis is created inside the anal canal itself, and a transanal surgical approach strongly worsened the incontinence domain, with beta coefficients of 0.437 and 0.860 respectively, but had much weaker effects on urgency and clustering. This pattern fits the anatomy: an ultra-low anastomosis and transanal dissection can directly injure the sphincter complex, undermining the mechanical barrier against leakage rather than the reflexes governing urgency.

Radiotherapy told a different story. Preoperative radiation worsened all three domains, suggesting it damages pelvic tissue in a broader, less selective way. Preoperative chemotherapy raised incontinence severity as well. Meanwhile, the age findings were the most striking and perhaps the most surprising. Compared with patients under 50, those aged 50 to 70 had greater incontinence-domain severity, consistent with an age-related decline in pelvic floor reserve. Yet patients aged 70 and older actually reported less urgency and clustering than the youngest group, with a negative beta coefficient of -0.257. The authors interpret this inversion as evidence that the two domains arise from different biology: incontinence from structural, anatomical vulnerability, and urgency with clustering from functional abnormalities, such as heightened visceral sensitivity and colonic hypermotility, that resemble diarrhea-predominant irritable bowel syndrome and tend to fade with age.

That distinction has immediate therapeutic implications. Patients whose suffering is dominated by urgency and clustering, often younger people, may respond to drugs that calm colonic hypermotility; the authors point to emerging evidence that 5-HT3 receptor antagonists such as ramosetron can relieve urgency and frequent stools in selected LARS patients. Patients with incontinence-dominant symptoms, by contrast, are more likely to benefit from physical rehabilitation of the pelvic floor and sphincter, including biofeedback and pelvic floor muscle training. A single composite score, the study argues, cannot tell these patients apart, because two people with identical LARS totals may occupy entirely different symptom worlds.

The study has important caveats, which the authors lay out candidly. It was conducted at a single center, and the three-factor structure was derived exploratively without confirmation in an independent cohort, so the domains remain hypothesis-generating rather than established. The LARS items were reweighted onto an ordinal severity scale before analysis, since the original score’s non-linear item weights were built for classification, not structural modeling. Questionnaire response fell to 66.9 percent at 24 months, and missing data were handled under a missing-at-random assumption without formal sensitivity analysis, meaning late symptom severity may have been underestimated. The analysis also excluded obstructed defecation and quality-of-life measures, which international consensus definitions consider integral to the full LARS construct, and the classification of very low anterior resection relied on the operating surgeon’s intraoperative judgment rather than a standardized anatomical measurement.

Even with those limitations, the message is hard to ignore. Postoperative bowel dysfunction, long summarized by a single number on a questionnaire, appears to be a family of related but separable conditions, each with its own anatomy, epidemiology and treatment logic. A domain-based approach, the authors conclude, offers a more precise framework for individualized functional assessment and could guide the design of future intervention trials, whether testing antihypertensive-style motility drugs for young patients with urgency-dominant disease or targeted pelvic floor rehabilitation for those with structural incontinence. For rectal cancer survivors, the difference between one blurred score and three clear domains may ultimately be the difference between generic reassurance and treatment that actually fits the problem.

Subject of Research: Symptom domain structure of postoperative bowel dysfunction after sphincter-preserving rectal cancer surgery

Article Title: Exploring Symptom Domains of Postoperative Bowel Dysfunction by Integrating LARS and Wexner Scores: A Longitudinal Factor‐Analytic Study

Article References: Matsumoto, Y., Takeshita, I., Shiokawa, K., Sahara, K., Munechika, T., Nagata, K., Nagano, H., Takahashi, H., & Hasegawa, S. (2026). Exploring Symptom Domains of Postoperative Bowel Dysfunction by Integrating LARS and Wexner Scores: A Longitudinal Factor‐Analytic Study. Annals of Gastroenterological Surgery, Article ags3.70289. https://doi.org/10.1002/ags3.70289

Image Credits: AI Generated

DOI: 10.1002/ags3.70289

Keywords: low anterior resection syndrome, LARS score, Wexner score, rectal cancer surgery, fecal incontinence, factor analysis, bowel dysfunction, urgency, pelvic floor, radiotherapy, patient-reported outcomes, mixed-effects models

The retrospective cohort study was conducted at the Cancer Institute Hospital of the Japanese Foundation for Cancer Research in Tokyo, one of Japan’s leading oncology centers. The investigators reviewed consecutive patients who underwent definitive rectal cancer surgery between January 2011 and December 2024. To keep the population homogeneous, they included only patients who had sphincter-preserving rectal resection with double-stapling technique reconstruction and a diverting stoma, all following radiation-based neoadjuvant treatment. Patients with Stage IV disease at surgery, those undergoing additional major procedures, and those with other reconstructive methods were excluded. Treatment strategy for each patient was determined at a multidisciplinary team conference, reflecting real-world institutional practice rather than trial protocol conditions.

The cohort was divided into two treatment eras of evolving intensity. A total of 168 patients received radiotherapy without additional preoperative systemic chemotherapy — the non-TNT group — comprising 135 patients treated with long-course chemoradiotherapy and 33 with short-course radiotherapy alone. Another 128 patients received total neoadjuvant therapy, or TNT, in which systemic chemotherapy is delivered before surgery, either before or after radiotherapy: 94 with a long-course chemoradiotherapy-based regimen and 34 with a short-course radiotherapy-based approach. TNT has become increasingly standard for locally advanced rectal cancer because Phase III trials have shown higher pathological complete response rates and, in selected patients, the possibility of organ preservation. The median patient age was 61 years, about 70 percent were men, and 71 percent had clinical Stage III disease.

The results on closure itself were encouraging. Stoma closure was achieved in 287 of 296 patients, a rate of 97 percent, and only five of those 287 patients — 1.7 percent — needed a stoma again within 30 days, a signal of an anastomotic problem missed during pre-closure assessment. That left 282 patients with what the researchers defined as initially successful closure. Before every closure, patients underwent contrast enema and endoscopic examination of the anastomosis, and surveillance computed tomography was added when more than six months had elapsed since the original operation. Closure proceeded only when no leakage, fistula, sinus, severe stenosis, or recurrence was evident. Even with this careful gating, the story did not end there.

During a median follow-up of 63 months after closure, 25 of the 282 patients — 8.9 percent — required delayed re-stoma creation more than 30 days after closure. The Kaplan-Meier estimates of delayed re-stoma-free survival were 93.3 percent at three years and 90.3 percent at five years. At the final follow-up, 258 of all 296 patients, or 87.2 percent, were stoma-free, while 12.8 percent lived with a permanent stoma. Strikingly, the timing and cause of re-stoma creation followed two distinct patterns that carry different clinical implications, the authors report.

Structural anastomotic complications were the leading cause, accounting for 14 of the 25 delayed events. These included delayed leakage, pelvic abscess, fistula, chronic sinus, and clinically significant stenosis — objectively confirmed anatomical failures severe enough to demand renewed fecal diversion. The median interval from closure to re-stoma in this group was 11 months. The researchers attribute these late failures to a convergence of mechanisms: persistent pelvic sepsis, impaired tissue healing, and progressive radiation-related tissue changes such as fibrosis and microvascular injury. Radiation, while essential for tumor control, leaves behind tissue that is fibrotic, poorly vascularized, and slow to repair itself — a hostile environment for an anastomosis that must remain intact for decades. A delayed leak may represent either an occult abnormality that became apparent only after bowel continuity was restored or a genuinely new failure of the irradiated tissue.

The second pathway was quieter and slower. Seven patients required re-stoma creation because of severe functional bowel dysfunction — defecatory impairment so disabling that patients elected fecal diversion despite having no structural abnormality on endoscopy or imaging. In these cases the median interval was 44 months, nearly four years after closure, and all seven stomas were permanent. This pattern echoes long-term randomized trial data showing that preoperative radiotherapy is associated with a higher prevalence of major low anterior resection syndrome even 14 years after surgery. Anatomical continuity, the study makes clear, does not guarantee functional success. One patient additionally developed dysmotility-related megacolon 46 months after closure, and three patients required re-stomas because of tumor recurrence at a median of 11 months.

Importantly, the intensification of treatment did not appear to worsen long-term stoma outcomes. Delayed re-stoma-free survival did not differ significantly between the non-TNT and TNT groups (log-rank p = 0.176), nor between long-course and short-course radiotherapy schedules within TNT. In an exploratory comparison, male sex was the only characteristic significantly associated with delayed re-stoma creation — 88 percent of re-stoma patients were men versus 67.7 percent of those who remained stoma-free (p = 0.040) — a finding the authors attribute cautiously to the narrower male pelvis and greater technical difficulty of deep pelvic reconstruction, while emphasizing it is hypothesis-generating given the small number of events. Age, diabetes, tumor height, anastomotic height, surgical approach, and lateral lymph node dissection showed no significant associations.

The study has limitations the authors acknowledge candidly. It was retrospective and conducted at a single high-volume center where treatment strategies evolved over 14 years. The number of delayed events was small, limiting statistical power, and the primary endpoint captured only clinically consequential deterioration requiring diversion — not the full spectrum of delayed anastomotic abnormalities or functional decline that patients may endure without a new stoma. Patient-reported bowel, urinary, and sexual function were not systematically collected, and the decision to create a re-stoma inevitably involves physician judgment and patient preference. Even so, the central message stands: approximately 90 percent of patients were ultimately stoma-free after radiation-based neoadjuvant treatment and sphincter-preserving surgery, and TNT was not associated with worse long-term stoma outcomes. The authors argue that sustained stoma-free status should be recognized as a clinically meaningful endpoint in its own right, tracked well beyond the day the diverting stoma is closed — with careful pre-closure imaging, continued vigilance for late anastomotic failure, and standardized assessment of bowel function in future studies.

Subject of Research: Long-term stoma-free outcomes after diverting stoma closure in rectal cancer patients treated with radiation-based neoadjuvant therapy

Article Title: Long‐Term Stoma‐Free Outcomes After Diverting Stoma Closure Following Radiation‐Based Neoadjuvant Treatment for Rectal Cancer

Article References: Ichikawa, H., Matsui, S., Sato, K., Noguchi, T., Sakamoto, T., Mukai, T., Yamaguchi, T., & Akiyoshi, T. (2026). Long‐Term Stoma‐Free Outcomes After Diverting Stoma Closure Following Radiation‐Based Neoadjuvant Treatment for Rectal Cancer. Annals of Gastroenterological Surgery, Article ags3.70279. https://doi.org/10.1002/ags3.70279

Image Credits: AI Generated

DOI: 10.1002/ags3.70279

Keywords: rectal cancer, diverting stoma, stoma closure, total neoadjuvant therapy, anastomotic complications, sphincter-preserving surgery, radiotherapy, low anterior resection syndrome, surgical outcomes, colorectal surgery, Long, Term