Clinical and metabolic features of patients for cancer

Oncological diseases, especially cancer, are characterized by intoxication and disruption of all metabolic links. The degree of expression of disorders depends on the localization, prevalence, and characteristics of the tumor process. Catabolic processes are most pronounced in patients with cancer of the digestive organs and in the development of complications of tumor growth (tumor decay, bleeding, obstruction at any level of the gastrointestinal tract, addition of purulent-septic complications).

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Metabolic disorder

Main article: Metabolic disorder

In cancer patients, as a result of the systemic effect of the tumor on the body, all types of metabolism (protein, carbohydrate, lipid, energy, vitamin and mineral) are disrupted.

Glucose hypermetabolism is a specific and constant manifestation of carbohydrate metabolism disorder in cancer patients. There is an acceleration of gluconeogenesis processes aimed at maintaining the glucose content in the blood plasma, which leads to the depletion of protein and fat depots.

Increased catabolism of body proteins is also typical for cancer patients and is accompanied by increased excretion of nitrogen in the urine and a negative nitrogen balance. Evaluation of the nitrogen balance is considered one of the most reliable criteria of protein metabolism, allowing timely diagnosis of the catabolic stage of the pathological process, selection of the optimal diet and assessment of the dynamics. During catabolism, structural proteins in muscles, vital organs and regulatory systems (enzymes, hormones, mediators) disintegrate, resulting in disruption of their functions and neurohumoral regulation of metabolism.

During the growth process, the tumor also uses fatty acids. In patients with normal natural nutrition, the required level of essential fatty acids in the blood plasma is maintained by mobilizing them from endogenous reserves of adipose tissue. The most profound lipid metabolism disorders are found in patients with gastrointestinal cancer; they are characterized by hyperlipidemia, an increase in the content of free fatty acids in the plasma due to replaceable ones, and a progressive loss of the body's adipose tissue mass, which leads to intensive disintegration of structural lipids in the blood plasma and cell membranes. Deficiency of essential fatty acids is detected; the severity of these disorders is associated to a greater extent with alimentary insufficiency.

A feature of the metabolism of cancer patients is a violation of vitamin metabolism in the form of a deficiency of both water-soluble vitamins of group C, B, and fat-soluble (A, E). A deficiency of antioxidant vitamins is associated with a decrease in the power of the antioxidant system of cell protection. Changes in oxidation-reduction processes in cells are characterized by the transition of tissue respiration to the anaerobic path and the formation of "oxygen debt". The blood of patients has an increased content of lactic and pyruvic acids.

Metabolic disorders are one of the triggers for activation of the hemostasis system, especially its platelet component, and suppression of the immune system. Hemostasis changes in cancer patients occur in the form of chronic compensated DIC, without clinical manifestations. Laboratory tests reveal hyperfibrinogenemia, increased platelet aggregation properties (degree of aggregation, platelet factor IV), increased levels of soluble fibrin monomer complexes, and circulating fibrinogen degradation products. Signs of DIC syndrome are most often observed in lung, kidney, uterine, pancreatic, and prostate cancer.

Immune system disorder

The overwhelming majority of cancer patients develop secondary immunodeficiency of varying severity with a decrease in all links of anti-infective immunity. Immune system disorders affect almost all of its links. The absolute number of T-cells is reduced, the number of T-suppressors is increased, their activity is significantly increased, the number of T-helpers and their functional activity is reduced, the proliferation of stem cells is suppressed, the processes of differentiation of stem cells into T- and B-lymphocytes are slowed down. There is a decrease in the indicators of natural and acquired humoral immunity, phagocytic activity of neutrophils.

The presence of a malignant tumor in patients is in itself an independent risk factor for the development of infection; infectious complications in cancer patients occur 3 times more often and are more severe than in patients with other pathologies.

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Anemia and Cancer

Anemia is a common complication of malignant tumors or their treatment. According to the ECAS (European anemia cancer survey), at the time of the initial diagnosis of a malignant neoplasm, anemia is noted in 35% of patients. The causes include general (iron and vitamin deficiency, renal failure, etc.) and specific to cancer patients:

• bleeding from a tumor,
• tumor lesion of the bone marrow,
• tumor disease anemia and toxicity of antitumor treatment.

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Features of preoperative examination

Preoperative examination and therapy are aimed at detecting disorders in vital organs for intensive therapy, which maximally restores organ functions. Most patients undergoing surgery (60-80%) have a variety of concomitant pathologies of the cardiovascular, respiratory and endocrine systems (hypertension, chronic non-specific lung diseases, diabetes mellitus, kidney pathology). Up to 50% of patients undergoing surgery are elderly patients (over 60 years old), of which about 10% are of senile age (over 70 years old).

Cancer patients have limited respiratory reserves, and respiratory failure of varying severity is observed in almost all patients with lung cancer, tracheal, mediastinal and gastrointestinal tumors. Even with normal external respiration function, postoperative pulmonary complications develop in 50% of cases of lung cancer, cardiac stomach cancer, and esophagus cancer. A decrease in vital capacity and respiratory reserves below 60% with a high degree of probability predetermines a severe course of the early postoperative period and prolonged mechanical ventilation. About a third of patients have respiratory failure of I-II degree, as a rule, these are obstructive at the level of small and medium bronchi and restrictive disorders. In patients with severe obstruction, special attention should be paid to forced vital capacity (FVC), forced expiratory volume in the first second (FEV1) and peak flow (PF). The FEV1/FVC ratio helps differentiate restrictive and obstructive diseases, it is within the normal range for restrictive diseases, since both indicators decrease, and in obstructive pathology it is usually reduced due to a decrease in FEV1. Postoperative mortality of patients with MVV is increased depending on age, the volume of surgical intervention and increases 5-6 times compared to the mortality of patients without respiratory pathology.

When assessing the patient's respiratory system prior to surgery, a thorough examination is necessary.

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Auscultation of the lungs

Bronchoscopy with sputum culture when the tumor is localized in the lung, esophagus, cardiac part of the stomach allows to assess the condition of the mucous membrane, the degree of colonization of the tracheobronchial tree and the nature of the microbial flora, which can become the causative agent of infection in the postoperative period.

In 50-70% of patients, serious cardiovascular diseases are detected, which reduce the functional reserves of the circulatory system and increase the risk of complications:

• IHD,
• history of myocardial infarction,
• rhythm and conduction disturbances,
• hypertension

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Volume of examination of patients

• 12-lead ECG.
• Bicycle ergometry.
• EchoCG (for patients over 60 years old).
• A complete blood count with determination of the white blood cell count (moderate leukocytosis and band shift in the absence of clinical manifestations of any infection are not indications for prescribing antibiotics before surgery).
• Sputum and urine cultures (if Candida albicans fungi are detected in sputum or urine, antifungal treatment is mandatory for 3-4 days).
• Screening assessment of renal function (blood urea and serum creatinine levels, urine analysis according to Nechiporenko). If an infection is detected, uroseptics must be prescribed.
• In case of renal failure, renal scintigraphy should be performed and creatinine clearance should be determined.
• Immunological studies help to identify secondary immunodeficiency of varying degrees of severity with a decrease in all links of anti-infective immunity.
• Intra- and postoperative monitoring of central hemodynamics in case of severe valve defects and a decrease in EF below 50%.