LI significantly reduced the risk of symptomatic AL, which is in line with other authors. [11, 12] However, LI was associated with a significantly higher risk of PS before and after PSM. In more than one-third of patients, the temporary LI was not closed after 18 months. Thus, the success of sphincter-saving surgical treatment is questionable. One of the reasons is probably our strategy to reverse ileostomy after the completion of adjuvant treatment. We assumed that our priority was the completion of oncological treatment. The optimal time to close the protective ileostomy after LAR has not been clearly determined yet. Early (8-13 days) reversal procedures have been shown to be safe in selected patients. [13, 14] However, there are reports that both early (<30 days) and late (> 6 months) stoma closure may be associated with an increased rate of postoperative complications. [15, 16] Despite several reports of good functional and oncological results of stoma reversal during adjuvant chemotherapy, there have been no known results of randomized trials to date. [17, 18] The occurrence of postoperative complications related to the closure of the stoma before or during adjuvant chemotherapy may be a reason to discontinue oncological treatment.
The prevalence of PS ranges from 9.5% to 33% in other studies. However, the results of most studies cannot be directly compared for several reasons. Some authors assessed the prevalence of PS in the whole follow-up [1, 8, 9, 16, 19, 20, 21], while others introduced the term “the latest expected time to closure” [2, 3, 22]. Additionally, the assumed latest expected time to closure was different, depending on the author, and even within the same analysis, times were different for patients who received complementary chemotherapy and those who did not . We believe that one of the reasons for the high percentage of PS in our analysis may be our adoption of an 18-month period after which we considered non-closed stoma to be PS. Interesting observations in this respect were provided by Gustafsson et al. who in the same material evaluated the prevalence of PS both during the whole follow-up and after the introduction of the latest expected time to closure and obtained the results of 17.1% and 31.6%, respectively . An additional factor that makes it difficult to compare different analyses is the fact that some authors included in their analyses tumours located not only in the lower rectum. In the assessment of PS risk factors in the group of patients with LI (group A), only preoperative and intraoperative factors were considered, since only these factors are useful when making a decision about creating LI. Postoperative factors described in the literature, such as AL, local recurrence or metachronous dissemination, cannot be used in the decision-making model. [19, 22, 23] In addition, we did not distinguish between primary (no qualifications for stoma closure) and secondary PS risk factors (complications after the reversal procedure). However, we searched for factors independent of the aetiology of PS. We did not confirm the impact of some of the PS risk factors described, such as age or the presence of comorbidities.  CCI proved to be an important factor in the univariate analysis, but only at >5, which was associated with the presence of synchronous distant metastases. The analysis did not show, however, the impact of specific diseases such as CAD or DM on PS risk. It seems that stage IV patients are not suitable candidates for LAR with LI, even in cases where the metastases are potentially resectable.
The only risk factor for PS in group A in the multivariate analysis was preoperative fibrinogen concentration. The obtained predictive values for preoperative fibrinogen concentration were insufficient for this variable to be considered an independent factor in the preoperative assessment of PS risk. However, the obtained PPV and NPV of 82.6% and 75.3%, respectively, indicated that the preoperative fibrinogen concentration may be useful in the decision-making model.
It has been shown that a high plasma fibrinogen concentration is associated with the development and progression of tumours. Although this phenomenon has not been fully understood yet, the hypotheses include the ability of fibrinogen to bind growth factors and tumour cells or affect the escalation of the inflammatory response in the tumour environment. These mechanisms lead to the proliferation of cancer cells and increase their invasive potential.  Fibrinogen concentration before treatment is a known prognostic factor not only in primary and metastatic colorectal cancer but also in other gastrointestinal cancers in terms of overall and disease-free survival. [26, 27] Additionally, the concentration of fibrinogen, which is also an acute phase reactant, is increased during the intense inflammatory response. It was also shown that presurgical systemic inflammatory response increases the risk of infectious postoperative complications, which also include AL. [28, 29, 30] In our material, 72% of the causes of non-closure of the stoma (Table 2) were related to the progression of the disease, local recurrence, death or anastomotic leakage. All these conditions are associated with an increased fibrinogen concentration. As a result, this factor was the only independent predictive factor of PS risk in the multifactorial analysis. At the same time, the analysis showed that above the cut-off point (fibrinogen concentration above 423.5 mg/dL) PS was found in 82% of patients in the group of patients with LI.
Obviously, these are preliminary observations that need to be confirmed and validated in other independent groups of patients with a protective ileostomy in order to confirm the importance of the elevated fibrinogen concentration as a factor increasing the risk of PS, which is known at the time of the decision to create an ileostomy.
Nonetheless, we have not shown the impact of the pre-treatment clinical stage of the disease, other than stage IV, on the risk of PS, although the stage of the disease is an important risk factor for metachronous metastases and survival. 
It is important to note a relatively high percentage of patients who did not agree to ileostomy reversal. It should be assumed that these patients were insufficiently informed about the treatment method or did not understand the information provided. This indicates the need to pay special attention to informing patients about the consequences of creating LI, including information about the risk of PS. In some of these patients, although sphincter preservation was technically possible, an abdominoperineal resection or low Hartmann’s procedure with a permanent colostomy should be considered, as these procedures have a lower risk of postoperative complications. Colostomy would be more beneficial than a permanent ileostomy. [21, 32, 33, 34]. When discussing the treatment plan, we need to ensure that the patient understands all the possible consequences of a diverting stoma. It should also be considered that patients with a higher education level are more likely to quickly undergo ileostomy closure.  In the absence of randomized studies on the impact of ileostomy closure time on long-term oncological results, we prefer to close the ileostomy only after adjuvant treatment. Furthermore, our analysis indicates a significant difficulty in performing a preoperative risk assessment of PS.
The analysis has the limitations typical of retrospective analyses. The decision to perform an ileostomy was always made subjectively by the surgeon. When analysing the percentage of protective ileostomies performed in the following years, there was a clear trend towards stoma creation. It was not possible to assess the total percentage of ALs, and only symptomatic ALs were detected, because in patients without an ileostomy, radiological examinations with a contrast enema were performed only in cases of suspected AL. Additionally, in the ileostomy group, radiological examinations were not performed in 11% of the patients. In our study, the percentage of symptomatic ALs in patients without an ileostomy may be biased since patients with a short follow-up were excluded from the analysis.