Primary Anastomosis Versus End-Ostomy in Left-Sided Colonic and Proximal Rectal Cancer Surgery in the Elderly Dutch Population: A Propensity Score Matched Analysis

The total study population consisted of 3286 patients (male/female: 1973/1313; median age 79 years), of whom 2661 (81%) received a PA and 625 (19%) received an EO. Within the PA group, a minority of patients received a defunctioning ostomy (n = 227, 9%). Most patients had an ASA classification of II (54%) or III (33%). Performance status was known for 1351 (41%) patients, of whom half had a score of 0. Comorbidity was registered for 54% of patients, and a large majority (79%) had a tumor located in the left-sided colon. There were considerable differences in patient and tumor characteristics between patients who received a PA and patients who received an EO (Table 1). Defunctioning ostomies were mostly ileostomies, while almost all EO were colostomies.

The PSM sample consisted of 1392 patients: 348 (57%) of the EO patients could be matched to 1044 patients in the PA group. There were no differences in patient and tumor characteristics between both groups (Table 1).

To our knowledge, this is the first nationwide population-based study focused on the short-term outcomes and 3-year survival in elderly patients undergoing left-sided colon and proximal rectal cancer surgery with PSM. Our data suggest non-inferiority of PA compared to EO in mortality up to 90 days, analyzing PSM samples. Therefore, both patients and surgeons should evaluate the true benefits of an EO, based on alleged mortality risks, within the first month after surgery.

Postoperative hospital stay was longer and more often prolonged in EO patients, also after multivariable analysis and PSM. Pre-existent comorbidity or functional dependency may lead to an extended length of stay. Furthermore, increased length of stay in EO patients might be attributable to the fact that they are not independent in their stoma care when they are medically ready to be discharged. Arranging home-visiting nursing services often takes a couple of days.11 Worth noting is that an easy standardized in-hospital educational stoma pathway improves the level of independence in new stoma patients and reduces the need for home-visiting nursing services12 Pre- and postoperative stoma education has shown to be effective in reducing the postoperative hospital stay in a younger population.¹³ It is a challenge to achieve the same positive effects of stoma educational pathways in the elderly population, and this may be an interesting subject for future research.

Deviating ostomies do not seem to influence the incidence of an anastomotic leakage in PA patients in our study. These findings, as well as the fact that deviating ostomies seem to ameliorate the consequences of a leak, have been previously reported.14,15 Our registry did not encompass details such as postoperative reinterventions, intensive care unit (ICU) admissions, or readmissions after discharge; therefore, we cannot conclude that deviating ostomies reduce clinically relevant leakages or possible consequences of a leak in the Dutch elderly population. Furthermore, the fact that an anastomotic leakage is defined in many different ways, makes it hard to compare findings between studies. This database only registers anastomotic leakages based on radiological findings (as stated above), which might have resulted in an underrepresentation. However, the definition of anastomotic leakage for the NCR did not change over time, therefore any possible underrepresentation would be the same for the total study population.

A striking finding in our study is the difference in overall and relative long-term (3-year) survival in disadvantage of EO patients. The decreased overall and relative survival in EO compared with PA was significant in univariable, multivariable, and PSM analyses. Even though the impact of an ostomy on quality of life in elderly patients has been previously reported,8,16 little can be found on the impact of an ostomy on the survival of elderly patients after CRC surgery. Our data show that patients with two or more comorbidities are more likely to receive an EO; however, univariable and multivariable analysis show that this degree of comorbidity does not influence survival.

Studies have shown that postoperative ostomy-related complications such as prolapse, necrosis, stenosis, retraction, leakage, and others can be as high as up to 70%.17 The possible complications or reoperations may worsen quality of life, mental status, or social functioning and could be detrimental for the elderly patient. This effect may be an additional cause for the significantly higher 60- and 90-day postoperative mortality that we found in elderly EO patients. Multivariable analysis showed that age ≥85 years, ASA IV, perforation at the time of surgery, and open surgery are not only risk factors for receiving an EO but also for dying within 90 days postoperatively. Various factors that may or may not be obvious, detected at the initial outpatient assessment but not included in the database, might have led to the surgeons’ choice for an EO instead of an anastomosis. For example, the severity of comorbidities or the interplay between comorbidity and functional status might be such factors. Ultimately, no method reduces confounding by unmeasured variables. Indeed, frailty (vulnerability due to a decline of interrelated physiological systems), weight loss, and disability (presence of restriction in at least one activity of daily living) are a few examples of those factors that influence the vulnerability and survival of the elderly patient.18,19 Specific preoperative assessment, such as a comprehensive geriatric assessment (CGA) helps in predicting postoperative morbidity and mortality.20 In particular, dependency in instrumental activities of daily living, depression, polypharmacy, and impaired nutrition are important in predicting postoperative complications and early mortality.20‐23 Previous research has shown that the occurrence of complications was the strongest risk factor for reduced survival in octogenarians.24 These results emphasize the importance of proper outpatient clinic consultation and the need for registration of the appropriate information regarding elderly patients beyond the standard given or measurable information that can be found in the medical charts. Performance scores, level of frailty, or CGA can be routinely assessed in clinical practice but unfortunately are not routinely documented in the charts or the data registries. In contrast, long-term survival is determined by a more complex interplay of non-surgical factors.

This study is also limited due to its retrospective, observational character and by the fact that occurrence of complications (other than anastomotic leakage and abscess) and causes of death are not registered in the NCR. The lack of complete information regarding the severity of comorbidities or performance scores are major limitations of this study, since both are important factors that can influence postoperative morbidity and survival. Relative survival was used in an effort to match cancer-specific survival as an estimation. This unfortunate shortcoming in the NCR data leaves many unknowns in our search for the exact causes of the survival differences in our elderly patients.

The downside of using PSM analysis is that the exclusion of patients from this analysis leads to loss of power. Nevertheless, PSM ensured the comparability of patients in both analyzed groups and provides additional information on subgroups in addition to the usual analysis in population-based data registries.

Relevant focus for further research would be to include more extensive data on performance scores, CGA, comorbidities, and postoperative complications that could lead to a European equivalent of the ACS NSQIP calculator and a better understanding of the survival and optimal treatment for our elderly patients with left-sided CRC. This information could be important for the decision making on surgical treatment in the elderly. Furthermore, repeating this analysis in 5 or 10 years, to evaluate the possible changes in EO rates and survival over time, as well as evaluation of interhospital variation in EO rates, would enrich the information for this decision making.

Despite the limitations of this study, one of its strengths is that it is based on the most comprehensive nationwide cancer registry with survival information that we have in The Netherlands. It shows real-life data and is a representation of our national elderly population with CRC. The discrepancies in 60- and 90-day mortality, as well as overall and relative survival, between patients with a PA and EO may be biased due to the different patient-specific factors, even though we have tried to correct for this using univariable, multivariable, and PSM analyses. Since there is significant difference in short-term mortality and overall and relative survival between patients with PA or EO in favor of PA, one might advocate that it is advisable to try to avoid the use of EO. A critical assessment on comorbidities, potential handling of an EO, age, and tumor stage will be necessary to argue in favor of an EO.