Features of fat assimilation in gastric cancer patients after gastrectomy

Stomach cancer is the leading cause of oncological morbidity in the digestive system, and the surgical method is the gold standard in its radical treatment. The proportion of gastrectomy among surgical interventions performed for stomach cancer is 60-70%, while the most justified from an oncological point of view and the most widely used option for reconstructing the gastrointestinal tract is the loop gastroplasty, in which food from the esophagus enters directly into the jejunum, bypassing the duodenum. After complete removal of the stomach, not only new anatomical relationships develop, the natural reservoir for the food taken is irretrievably lost, gastric motility, which ensures the rhythmic flow of food, falls out, but also the food taken is processed with hydrochloric acid, which ultimately affects the absorption of its main ingredients. Due to the development of new conditions for the functioning of the entire digestive system, one of the compensatory mechanisms after gastrectomy is the increased formation of intestinal hormones, increased secretion of intestinal enzymes by the mucous membrane of the initial sections of the jejunum, which ensure the breakdown of food. The catalyst in this case is the food consumed, which affects the extensive receptor field of the mucous membrane of the jejunum. An indispensable condition for normalizing the rhythm of the liver and pancreas is the prolonged effect of food on the receptor field of the mucous membrane of the jejunum.

According to researchers involved in the problems of digestive adaptation, after complete removal of the stomach, some digestive disorders can be prevented by creating a food reservoir in the initial section of the jejunum, which performs a number of functions, the main ones being the provision of food deposition and its rhythmic entry into the intestine. To date, a large number of methods have been proposed for restoring the reservoir for ingested food, and some authors directly speak about creating a so-called artificial stomach. However, a large number of proposed gastroplasty options only emphasizes the unsatisfactory functional results and the need to search for new methods of reconstruction. One of the main criteria for the advantages and disadvantages of certain methods of restoring the continuity of the digestive tract after gastrectomy is to determine the degree of disruption and compensation of metabolism. Digestive processes after gastrectomy, especially the state of protein and carbohydrate metabolism, have been studied quite well. As for the features of fat metabolism in various gastroplasty options, the literature data are few and contradictory.

In this work, we focused on the study of the characteristics of fat absorption in patients after gastrectomy in a comparative aspect with various reconstruction options, including a new version of gastroplasty.

The aim of our study was to investigate the characteristics of fat absorption in patients with gastric cancer after gastrectomy with various types of gastroplasty.

A total of 152 patients with stomach cancer who underwent gastrectomy with different types of gastroplasty were examined, including 89 (58.6%) men and 63 (41.4%) women. The average age of the patients was 59.1±9.95 years (27 to 80 years). All patients were divided into two comparable observation groups. The patients were allocated to groups in a blinded manner using envelopes that included recommendations regarding the gastroplasty technique during gastrectomy. The main group included 78 patients with stomach cancer - 45 (57.7%) men and 33 (42.3%) women aged 58.8±9.96 years, who underwent a new type of gastroplasty during the reconstructive stage of gastrectomy, which involves the formation of a reservoir for ingested food in the initial section of the jejunum. The control group included 74 patients with gastric cancer - 44 (59.6%) men and 30 (40.5%) women aged 59.7±9.63 years, who underwent gastrectomy using the traditional loop gastroplasty technique, known in the literature as the Schlatter method.

The studies were conducted upon admission of patients to the hospital, on the eve of surgery, the data obtained were considered as initial, as well as in remote observation periods. Examination of patients in a hospital setting has invaluable advantages, as it allows for a range of laboratory studies and the full identification of digestive abnormalities. Therefore, at various times from 6 to 36 months after surgery, we hospitalized our patients for a comprehensive examination. Dynamic functional examination in remote observation periods was performed on those patients who were not diagnosed with distant metastases or tumor recurrence after ultrasound, radiological, endoscopic studies, as well as computed tomography data.

An essential condition was uniformity in the nature of the food consumed in all time periods. The nutrition of patients in both groups was three times a day and included a mixed type, containing all necessary nutrients in moderate but sufficient quantities, including 110-120 g of protein, 100-110 g of fat, 400-450 g of carbohydrates with an energy capacity of 3000-3200 calories.

The existing methods of studying fat metabolism (radioisotope method of determining the products of absorption and excretion of radioisotope-labeled food, determination of blood serum lipids, chylomicron counting, determination of vitamin A absorption) are extremely complex, labor-intensive, and difficult to access in everyday practice, while the results obtained are sometimes contradictory. We have used a simple but very indicative method of determining the absorption of the main food ingredients based on coprological examination as the basis for studying the nature of absorption of fats coming with food. Of the residues of fat products in feces, only fatty acid salts are normally found in small quantities. Neutral fat and fatty acids are absent in normal feces. Impaired fat absorption - steatorrhea - can be associated either with insufficient lipolytic activity of pancreatic enzymes, or with impaired bile flow into the intestine, or with accelerated transit of food through the intestine. In case of disturbance of exocrine activity of the pancreas, steatorrhea can be pronounced and is represented exclusively by neutral fat (the so-called steatorrhea type I). In case of disturbance of bile flow into the intestine, there is a slow activation of pancreatic lipase and disturbance of fat emulsification, which in turn hinders the action of enzymes. Therefore, in case of deficiency or absence of bile in the intestine, steatorrhea is manifested by a large amount of fatty acids and neutral fat (the so-called steatorrhea type II). Unlike fatty acids with a short carbon chain, which are freely absorbed in the proximal part of the small intestine, bypassing any transformations in the intestinal wall, sodium and potassium salts of fatty acids with a long carbon chain, the so-called soaps, form micelles stable in an aqueous medium, for the absorption of which a longer process of micellar diffusion is necessary. Consequently, the presence of a large amount of fatty acids and soaps in the feces indicates a violation of absorption (the so-called steatorrhea type III), which occurs with accelerated movement of food masses through the small intestine.

The quantitative assessment of the structures was carried out according to certain rules and was expressed as a number of pluses. Statistical processing of the research materials was carried out in accordance with modern international standards of clinical research practice.

When studying the characteristics of fat absorption, it is impossible not to take into account the preoperative baseline parameters. It was the parameters on the eve of the operation, and not in the early postoperative period, when the patients' nutrition cannot be considered normal, that were the baseline. On the eve of surgery, neutral fat was detected in 9 (11.5%) of 78 patients in the main group and in 9 (12.1%) of 74 patients in the control group, fatty acids were detected in 5 (6.4%) patients in the main group and in 5 (6.7%) patients in the control group, fatty acid salts - in 8 (10.2%) and 7 (9.4%) patients, respectively. Thus, on the eve of treatment, 5 (6.4%) patients of the main group and 5 (6.7%) patients of the control group were diagnosed with impaired fat absorption caused by insufficient lipolytic activity of pancreatic enzymes, in 6 (7.7%) patients of the main group and 5 (6.7%) patients of the control group these disorders were caused by impaired flow of bile into the intestine, which can be explained by the fact that 12.3-12.9% of our patients have hypokinetic motility disorders of the biliary tract. Taking into account the number of diagnosed fatty acid salts in 4 (5.1%) patients of the main group and in 3 (4.1%) patients of the control group, the enteral nature of fat absorption disorders was present to a lesser extent on the eve of surgery. In general, as can be seen from the presented indicators, 15 (19.2%) patients of the main group and 13 (17.5%) patients of the control group were diagnosed with impaired fat absorption on the eve of surgery, which indicates the comparability of the studied groups of observations.

Based on the presented data, it can be noted that after gastrectomy, the processes of fat digestion worsen. Six months after the operation, normal fat absorption was diagnosed in 40 (64.5%) patients of the main group and in 36 (61.1%) patients of the control group, which is significantly lower compared to the preoperative data (80.8% and 82.4%, respectively). Subsequently, as the time elapsed after the operation increases, the frequency of fat absorption disorders has a clearly expressed dependence on the type of gastroplasty used. Thus, among patients of the main group, during 24 months after gastrectomy, the number of patients with impaired fat absorption fluctuated within 35.5-38.2%. By 36 months of observation, the number of patients with impaired fat absorption decreased to 33.3%, which indicates some stabilization of fat metabolism in patients with a formed small intestinal reservoir. In patients of the control group, during 24 months after the operation, an increase in the number of patients with impaired fat absorption was noted from 38.9% to 51.7%, which exceeded similar indicators of patients of the main group. By the third year after the operation, the number of patients with impaired fat metabolism decreased, but the number of patients with impaired fat absorption in the control group was greater compared to patients of the main group. In this regard, it can be noted that in the first two years after gastrectomy, in patients with an artificially formed small intestinal reservoir, the processes of compensation for impaired digestion, primarily associated with fat metabolism, proceed better compared to patients who underwent the traditional method of gastroplasty.

Figure 2 shows the data of a coprological study reflecting the absorption of the main products of fat metabolism in patients of the examined groups both on the eve of surgery and in the late periods after surgery.

On the eve of surgery, the content of the main products of fat metabolism in the feces of patients in both groups was the same. Already 6 months after the operation, the number of patients in the main group who were found to have neutral fat in the feces increased by 4.6%, among patients in the control group - by 8.2%. There was an increase in the number of patients in whom fatty acids were found in the main group - by 9.7%, in the control - by 11.9%. The number of patients diagnosed with fatty acid salts in the feces in the main group increased by 4.3%, in the control - by 12.6%. Subsequently, as the time elapsed after the operation increased, this difference only increased. Thus, the greatest number of patients in whom neutral fat was found in the feces in the main group was registered in the second year of observations (20.5% of patients), in the control group - two years after the operation (31.0% of patients). Two years after the operation, the maximum number of patients with fatty acids in their stool was registered, both in the main (23.5% of patients) and in the control group (34.5% of patients). In turn, the greatest number of patients with fatty acid salts in their stool occurred during the 18-month observation period - 20.0% of patients in the main group and 26.3% of patients in the control group. According to the presented data, several conclusions can be made. Firstly, in the control group, in all periods of remote observation after the operation, a greater number of patients were found with fat metabolism products in their stool, which should not normally occur, which in turn indicates insufficient fat absorption processes. Secondly, three years after the operation, both among patients in the main and control groups, a decrease in the main indicators characterizing fat metabolism insufficiency is observed, which may indicate some adaptation of compensatory processes.

The table shows the frequency and type of diagnosed steatorrhea among patients in the examined groups during different observation periods.

On the eve of the operation, the number of patients with various types of lipid absorption disorders did not differ significantly in the examined groups (19.2% of patients in the main group and 17.5% of patients in the control group). Six months after the operation, the number of patients with lipolytic steatorrhea in the main group increased by 6.5%, with cholemic steatorrhea by 5.2%, and with enteral steatorrhea by 4.6%. Among patients in the control group, the number of patients with lipolytic steatorrhea increased by 6.8%, with cholemic steatorrhea by 8.5%, and with enteral steatorrhea by 6.1%. The data indicate that six months after the operation, the number of patients with various types of lipid absorption disorders among patients in the control group exceeds similar indicators among patients in the main group. This difference only increased in the long-term observation periods. Thus, the greatest number of patients with lipolytic type of steatorrhea was registered among patients of the main group 24 months after surgery (14.7% of patients), among patients of the control group - 18 months after surgery (15.8% of patients). The greatest number of patients with cholemic type of steatorrhea was registered both among patients of the main and control groups, 18 months after surgery (15.5% and 15.8% of patients, respectively). The greatest number of patients with enteral type of steatorrhea among patients of the main group was noted 6 months after surgery, and among patients of the control group - 24 months (9.7% and 20.7% of patients, respectively).

As for the ratio of different types of lipid absorption disorders among patients in the examined groups, we consider the following observation to be important. Among patients in the main group, the share of steatorrhea associated with insufficient lipolytic activity of digestive secretions or with impaired bile flow into the intestine accounted for 33.3% on the eve of surgery, while among patients in the control group it was 38.5%. Six months after surgery, this ratio among patients in both groups was approximately equal (36.4% and 34.8%, respectively). Throughout the observation period, it changed, with patients in the main group predominating, and with increasing time after surgery, this ratio increased. At the same time, the share of steatorrhea associated with impaired absorption of fat breakdown products accounted for 66.7% in patients in the main group on the eve of surgery, while in patients in the control group it was 61.5%. Throughout the observation period, this ratio also changed. Thus, after 6 months, the number of patients with impaired fat absorption among patients of the main and control groups was 63.6% and 65.2%, respectively, 12 months after the operation - 63.2% and 68.4%, 18 months - 64.7% and 66.7%, 24 months - 61.5% and 73% and three years - 60% and 75%, with a predominance of patients in the control group. Taking into account the previously conducted X-ray and radioisotope studies demonstrating accelerated movement of the radiopaque food mixture and radioisotope-labeled natural food through the intestine in patients of the control group, it can be concluded that patients with traditional gastroplasty have impaired fat absorption associated with accelerated transit of nutrients through the gastrointestinal tract. Thus, based on the presented data, the following conclusions can be drawn. Patients with stomach cancer initially show signs of impaired fat absorption, and gastrectomy leads to an even greater deterioration in fat metabolism, especially in the first two years after surgery. The choice of gastroplasty method affects the severity of impaired fat absorption from food. Considering that in patients with stomach cancer, who had a reservoir formed in the initial section of the jejunum during the reconstructive stage of gastrectomy, the number of patients with enteral absorption disorders of fat breakdown products was 60%, which is significantly less than the number of patients with the traditional gastroplasty method - 75%, this makes it possible to conclude that the proposed gastroplasty option helps improve fat metabolism in patients with stomach cancer after gastrectomy.

Prof. Yu. A. Vinnik, Assoc. Prof. V. V. Oleksenko, Assoc. Prof. V. I. Pronyakov, Ph.D. T. S. Efetova, V. A. Zakharov, E. V. Strokova. Features of fat absorption in patients with gastric cancer after gastrectomy // International Medical Journal - No. 3 - 2012

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