Due to the evolution of surgical techniques and instruments, the development of circular staplers, total mesorectal excision, and preoperative chemoradiation, low anterior resection (LAR) has become a routine procedure in distal rectal cancer that allows anal sphincter preservation. Anastomotic leakage (AL) remains one of the most threatening complications after LAR.^[1] Postoperative AL is a serious event that affects quality of life (QOL), increases morbidity and mortality rates, and worsens the oncological outcomes. Diverting stoma can prevent or decrease the incidence of leakage and subsequent septic complications.^[2-6] While diverting stomas are usually temporary, around approximately 20% of temporary stomas are never closed or are converted to an end colostomy.^[7,8] Multiple reviews and analyses have shown that factors significantly increasing the risk for permanent stomas include advanced age, local recurrence, stoma-related complications, and impaired anal sphincter function, caused by denervation during surgery or due to neo- or adjuvant radiotherapy. Despite the evolution of medical and surgical science, these risk factors are not well established.^[9]

The aim of this study was to identify the risk factors that could transfer temporary stoma to a permanent one after low anterior resection.

The study was designed as a prospective, single-center analysis of patients with rectal cancer from the 1st of January 2017 until the 31st of May 2023. Preoperative screening and patient recruitment were performed in the Department of Gastroenterology and the Department of Surgery at Kaspela University Hospital in Plovdiv. For the described period, we reviewed a total of 418 histologically confirmed rectal cancer patients who underwent low anterior resection with a temporary diverting ileostomy. The exclusion criteria for patients were: 1) advanced disease with multiple liver or peritoneal metastases requiring subsequent palliative procedures; 2) emergency surgery necessitating ostomy creation in a Hartmann fashion; 3) recurrent rectal cancer following previous surgery; 4) patients with only radiologically demonstrated anastomotic leakage without clinical signs.

A total of 348 patients were enrolled in our analysis and divided into two groups: group A, the group of patients with temporary stomas, and group B, patients with permanent stomas (stoma re-creation after reversal and stoma non-reversal after diversion).

Every patient was diagnosed with rectal cancer through a colonoscopy, biopsy, and histological examination. Anastomotic complications included stricture, fistula, leakage, and the formation of a pelvic abscess. Leakage is defined as communication between the intraluminal and extraluminal compartments caused by a defect in the intestinal wall’s integrity at the anastomotic area, between the colon and rectum/anus, with clinical signs of peritonitis and radiological findings of extraluminal air, fistula, or intra-abdominal abscess.

In 2010, the International Rectal Cancer Research Group defined postoperative anastomotic leakage after surgical treatment of rectal cancer and further graded it as follows:

Grade A is defined as subclinical anastomotic leakage (also known as “imaging anastomotic leakage”) without clinical symptoms or a requirement for special treatment.

Grade B is characterized by abdominal pain, fever, and purulent or fecal-like drainage from the anus, drainage tube, or vagina (rectovaginal fistula); an increased white blood cell count and C-reactive protein concentration; and anastomotic leakage, requiring conservative treatment.

Grade C is characterized by peritonitis, sepsis, and other clinical manifestations of Grade B anastomotic leakage, which require secondary surgery. Following the above standards, patients who met any one of the following four criteria were determined to have anastomotic leakage in the present study: the drainage tube near the pelvic anastomosis drained intestinal contents or had a fecal odor; outflow of contrast agent was observed by digestive tract radiography, gas accumulation and intestinal wall discontinuity were found around the anastomosis site by computed tomography examination, or the anastomotic opening was confirmed by anal palpation using a finger. These findings were combined with other clinical evidence of anastomotic leakage, such as fever, chills, positive blood culture, or high leukocyte count.

After mobilization, the length of the colon was grossly estimated, and, subsequently, the need to mobilize the splenic flexure was assessed. The inferior mesenteric artery (IMA) pedicle was isolated and doubly ligated. The inferior mesenteric vein (IMV) was also ligated. The bowel was subsequently transected at a level ensuring adequate blood supply to the remaining colon. A total mesorectal excision (TME) was undertaken for adequate oncologic resection. After identifying the sympathetic nerves over the pelvic brim, electrocautery was used to dissect in the posterior avascular, alveolar plane between the fascia propria of the rectum and the parietal fascia of the pelvic floor structures while the rectum was being retracted anteriorly. This procedure, when undertaken accurately, allows for the sparing of autonomic nerves as well as the surrounding pelvic structures and results in a smooth mesorectal specimen. Middle and distal rectal tumors require the removal of the entire mesorectum. Multiple studies have indicated that a 2 cm margin of the mucosa is likely more than adequate.

Mobilization of the rectum and the level of transection has been established. The mesorectum was divided with bipolar ligation. The rectal wall was transected using a stapling device, a thoraco-abdominal linear stapler, or an endo GIA stapler dependent on the width of the pelvis. The length of the proximal colon was then evaluated for the construction of a tension-free anastomosis. If more length was needed, a variety of maneuvers were employed. The size of the end-to-end anastomosis (EEA) stapler was decided by the caliber of the colon.

After completion of the anastomosis, anastomotic integrity was tested by an air leakage test. Patient withdrawal from the study was warranted if a primary leak of the anastomosis was identified intraoperatively. Each case with a primary leak after air insufflation underwent anastomotic repair and fecal diversion. An intra-abdominal drain was placed in the pelvis at the end of the procedure.

Patients with only radiologically demonstrated anastomotic leakage without clinical signs were excluded from the investigation.

The anal stricture was defined as the narrowing of the anastomotic area that requires invasive procedures such as dilation, manually or with a Hegar dilatator. Early anastomotic-related complications were those occurring within 3 months after surgery, while the others were classified as late.

Patients were followed up four times per year for the first two years after surgery and then two times for the next three years. A colon enema with water-soluble contrast and anoscopy or digital rectal exam was performed to determine and evaluate if abnormalities such as leakage or stricture were present.

There were 348 patients in our study, and 324 (93.1%) received a stoma reversal. The median period between primary surgery and stoma reversal was 3.5 months. After a median follow-up of 50.4 months (range 6‒106 months), 324 patients were confirmed to have had a temporary stoma, while 24 (6.9%) were found to have permanent stomas. Of the 24 permanent stoma patients, there were 12 ileostomies (50.0%), 6 colostomies (25.0%), and six patients with abdominoperineal resections (25.0%) due to total dehiscence of the anastomosis.

The characteristics of the temporary and permanent stoma groups are shown in Table 1.

The risk factors for permanent stoma include anastomotic-related complications (p=0.001) and local recurrence (p=0.001). Multivariate analysis showed that the independent risk factors for permanent stomas were local recurrence [OR, 5.050; 95% (CI), 1.867‒13.659; p= 0.001] and anastomotic-related complications (OR, 4.369; 95% CI, 1.631‒11.701; p=0.001) The multivariate analysis revealed that sex, tumor-node-metastasis stage, and permanent stomas were independent prognostic factors for disease-free survival (Table 2).

The characteristics of the patients who needed a permanent stoma, including stoma recreation after the reversal (stoma recreation group, n=12) and stoma non-reversal after diversion (stoma non-reversal group, n=12), are shown in Table 3. There were no significant differences between the two groups.

The factors that lead to permanent stomas in our patients are compared in Table 4. In the stoma recreation group, there was local recurrence, stoma complications, obstructions, and poor sphincter function, whereas in the stoma non-reversal group was local recurrence and obstruction. Concerning anastomotic-related complications between the two groups, the stoma recreation group was associated with late complications more often than early (early: late, 0:5) compared with the stoma non-reversal (early: late, 2:3).

Diverting loop ileostomies have become a common procedure when low rectal anastomosis is performed. Some authors consider that ostomy creation can reduce morbidity and avoid early resurgery if a leak occurs, but it does not affect the leakage rate. Fecal diversion is also associated with complications in the early postoperative period, after hospital discharge, and the patients need another surgery for ostomy closure. Some stomas are never reversed or, after takedown, need re-stomy.^[10,11] The permanent stoma rate after low anterior resection has been reported to vary between 3 and 24%.^[12-14] If we focus on the most commonly performed diverting loop ileostomy, its non-reversal rate is in the range of 13.8‒24.9%.^[15-17]

In the present study, 3.44% of patients (12 of 116) had a permanent stoma, and the same percentage, 3.44 (12 of 116), had no reversals of diverting loop ileostomy. Local recurrence is one of the major factors of permanent stomas in rectal surgery. Few studies, Seo et al., Mala et al., and Junginger et al., reported that local recurrence is the main purpose for protective ostomies to become permanent.^[18,19] In our study, local recurrence was also the primary cause of a permanent stoma and was followed by anastomotic-related complications.

When we focused on the factors for ostomy recreation after its takedown, the results were the same. Lim et al. and Song et al. reported similar results, indicating that local recurrence is the main factor for requiring stoma recreation after stoma closure. They specifically reported that 10 of 18 patients (55.6%) with permanent stomas had stoma recreation due to local recurrence.^[20,21]

Many authors try to identify risk factors to create a predictive score system and find out that advanced age, radiation therapy, poor anal function, and distant metastasis significantly increase the risk for a permanent stoma. Systematic reviews and analysis have reported that old age is one of the most significant factors for permanent stomas^[22-24], while other surgeons do not agree with that^[25]. Den Dulk et al. suggested that comorbidity in elderly patients often leads them to refuse another risky surgery to perform an ostomy takedown.^[26-28]

Some authors consider that chemo and/or radiation therapy is also important for permanent stomas due to the often association between neoadjuvant therapy and anastomotic-related complications^[29], but others, like Waterland et al., disagree with this^[30]. We support the first hypothesis, after analyzing the results and observations of our study, that chemo and/or radiation therapy was a significant factor for a permanent stoma. Poor anal function and distant metastasis are also associated with a high risk for permanent stomas, but we do not evaluate them in our analysis.

The stoma takedown time is variable. Some surgeons reported a period between the first procedure and ostomy closure of 4‒5.6 months.^[31] In the present study, our median time for stoma reversal was 13 weeks, which is in agreement with other authors’ reports.^[31]

Some scientists suppose that nearly 21% of the cases with no reversed stoma were due to physician-related reasons. This suggests that certain surgeons and oncologists prioritize tumor treatment over the patient’s quality of life.^[31]

The limitations of our study include its non-randomized design and the small number of patients with a permanent stoma.

In conclusion, anastomotic leakage, local recurrence, and neo-adjuvant or adjuvant chemotherapy and/or radiation therapy could be important risk factors for the stoma’s nonclosure or re-creation in low rectal cancer patients. Surgeons should be more alert in the stoma closure of these risk patients. In addition, there are no clear criteria for protective stoma creation. Usually, this decision depends on surgeons’ personal preferences. Unfortunately, we did not evaluate anal function, which may be an important risk factor for permanent stomas. Future research and meta-analysis are needed to facilitate surgeons’ decisions in these “risky” patients.