Chemotherapy Of Malignant Tumors Biology Essay

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-Chemotherapy of malignant tumors - is the use for therapeutic purposes drugs that inhibit the proliferаtion оr irreversibly damaging tumor cells. In a broad sense, this term reflects treatments of malignant neoplasms, related to the effect of pharmacological funds directly to the tumor. The most fully all аsрects chemotherapy of malignant tumors reflects the term "drug therapy of tumors, implying the use of synthetic drugs substances of natural origin, antibiotics, hormones and other anticancer funds. However, both terms are acceptable

Chemotherapy of malignant tumors is an independent and promising area of oncology, the role which each year increases. This is due to significant advances in the field research and study of anticancer drugs, to clarify their pharmacokinetics and mechanism of action, as well as the prospect of a rational and purposeful their use in combination with surgery and radiation therapy. Currently, chemotherapy of malignant tumors had reached a level allows to distinguish groups of common forms of malignant tumors, which can be fundamentally healed in more than 50% of cases with a single drug method. These include lymphoma, horionkartsinoma cancer, Burkitt's tumor, germ cell testicular tumors, acute lymphoblastic leukemia in children.

In the treatment of virtually every patient with malignant

tumors considered whether to proceed


The main tasks of the medicinal methods:

♦ increase the frequency and duration of complete remissions;

♦ an increase in life expectancy;

♦ improve the quality of life.

Indications for the use of chemotherapy is a primary

common process and the development of disease recurrence after local

treatments. Widespread:

♦ adjuvant chemotherapy (directed at reducing the risk of

recurrence of the disease by acting on micrometastases after

surgical or radiation treatment of the primary tumor).

♦ neoadjuvant chemotherapy (the use of chemotherapy before surgery

or radiation therapy to reduce the size of tumor masses and subsequent evaluation of their sensitivity to cytostatic drugs used).

Neoadjuvant chemotherapy is justified:

1) better penetration of cytotoxic drugs in the intact tumor;

2) a decrease in tumor mass, allowing to reduce the amount of therapy;

3) early eradication of micrometastases;

4) the possibility of using higher doses of cytotoxic drugs;

5) assessment of individual sensitivity of tumors to cytostatic drugs,

which is important for planning further therapy.

By way of anticancer agents are following

types of chemotherapy:

1. System - is designed for general (resorptive), antitumor

effect. Drugs are introduced into the subcutaneous, intravenous, intramuscular

and rectally.

2. Regional, elevated concentrations of the cytostatic influence

the tumor by injection into the vessels feeding the tumor;

while limiting intake of the drug in other organs.

3. Local - the application of appropriate dosage forms on the surface

foci, the introduction of a serous cavity with effusion, intravesically

or into the spinal canal.

The most widespread systematic Combination chemotherapy.

General principles of chemotherapy

Cancer cells need to be sensitive to the cytostatic drugs used.

2. The drug must reach the tumor cells (for example, to penetrate

through the BBB with brain metastases).

3. If the drug is effective only in one phase of the cell cycle, it must

introduced so often that all tumor cells have been this phase

during his presence in the body.

4. Tumor cells must be destroyed before they become resistant

to cytostatics.

5. Combination chemotherapy more effective use of cytostatics in mono.

Modern oncology has the ever-expanding arsenal of

chemotherapeutic agents that are used with the aim of eradication

tumor tissue, or - if the optimal goal is unattainable - the maximum

reduce tumor mass, to achieve significant remission

and increase survival.

A crucial role in the effectiveness of antitumor action often

played dose chemotherapy.

When choosing drugs for chemotherapy, the following

Principles (De Vita V. et al., 1993):

1. Drugs should have a moderate or high efficiency

at a given location of the tumor.

2. In the presence of several drugs of one class, with close

efficiency, preference is given to the least toxic.

3. Using the most effective treatment and dosage.

4. Preferable to combine cytotoxic agents with different mechanisms

action and spectrum of toxicity.

5. The combination of cytotoxic drugs should be applied at regular intervals,

which should be as short as possible and to ensure recovery

Only the most sensitive organs (primarily

bone marrow).

A crucial role in the effectiveness of antitumor action often

played dose chemotherapy. It is shown that a decrease in dose intensity

reduces the frequency of positive effect and / or overall survival in some types of cancer. The significant increase in dose in most cases impossible because of the development

adverse reactions caused by damage to normal organs

and tissues. Close conjugation of therapeutic and toxic effects is

feature of the drug therapy of malignant tumors. Low

selectivity of chemotherapy due to the fact that the progenitors of tumor

are normal cells. Most vulnerable to cytotoxic chemotherapy

reproductive organs, lymphoid tissue, hair follicles,

epithelium of the gastrointestinal tract and bone marrow.

ML Gershanovich in 1982, first published clinical classification

complications of chemotherapy of tumor diseases, which still

not lost its importance.

I. Complications associated with toxic (cytotoxic) action


1. Local irritant (non-specific action): toxic dermatitis,

inflammatory infiltrates and necrosis of subcutaneous tissue

phlebitis, aseptic cystitis and serozity (pleurisy, peritonitis, etc.).

2. System, relatively non-specific side effects: myelo-

depressed, dyspeptic syndrome, skin lesions and its appendages,

mucous membranes, impaired reproductive function.

3. System, a relatively specific side effects: neyrotok-

classical, hepatotoxic, pankreatotoksicheskoe, cardiotoxic

actions, lung, urinary tract, blood coagulation

blood system, visual system, endocrine and metabolic disorders

chromosomal abnormalities, teratogenic effects, carcinogenic

effect (the appearance of secondary tumors).

II. Complications associated with immune imbalance

1. Immunosuppressive effect: intercurrent bacterial, fungal,

viral and protozoal infections (Fig. 6.11-6.13), exacerbation of chronic

focal infection, the progression of cancer.

2. Allergic reactions: allergic dermatitis, allergic pul-

Monet, the general reaction of anaphylactic type.

3. Autoimmune reactions: leukopenia, agranulocytosis, thrombocytopenia,

hemolytic anemia, vasculitis.

III. Complications caused by intolerance to cytostatic (congenital

hypersensitivity, idiosyncrasy)

1. Any (unexpected) complications, but most often associated with major

cytotoxic properties of the drug (mielodepressiya, independent

on the dose, etc.).

2. Paradoxical and unusual pharmacological action of drugs

reactions (fever, etc.).

IV. Complications caused by the interaction of the body cytostatic

with other drugs (including those with other anticancer drugs)

1. Enhancing inherent cytostatic effects.

2. Unusual manifestation of cytostatic side effects due to the formation

new metabolites and other mechanisms.

3. Strengthening cytostatics toxicity of other pharmacological


Determination of the toxicity in accordance with the recommendations

WHO (1979), which described in detail the main types of collateral

action of anticancer drugs. According to terms of all the complications are divided into immediate,

immediate, delayed and delayed.

Immediate complications (vomiting, nausea, drug fever,

hypotensive syndrome, various types of allergic reactions) are observed

in the first hours after drug administration.

Surrounding side effects (mielodepressiya, dyspeptic syndrome,

neurological disorders, toxic lesions of the urinary system

pancreas, lung, myocardium, immunodepres-

Sia) manifest themselves in the process of chemotherapy more frequently by the end of treatment.

The same reaction, but are up to 6 weeks after completion of treatment,

called delayed. Regardless of the application himiopre-

Parata delayed, as a rule, liver function abnormalities,

infarction, bone marrow.

For long-term complications include those that develop within 6 -

8 weeks after completion of the course (teratogenic, carcinogenic effect).

The appearance of the immediate and delayed complications may lead to

temporary cessation of treatment, and sometimes to the abolition of the latter.

The most common for most drugs are the complications associated

with cytotoxic effects on tissues with severe proliferative

activity. Obviously, the most frequent complication during chemotherapy

is toxic leukopenia.