Cancer is abnormal tissue formed from one “sick” cell in the body. It grows as a result of uncontrolled cell division, combined with a simultaneous disturbance of the differentiation of the resulting cells.

The body loses control over the process of cell multiplication as a result of mutations of various genes that code for proteins that play an important role in the cell cycle. These genes are called proto-oncogenesandantincogens.

Some of the tumors that develop in humans are hereditary – they account for about 5-10% of all neoplastic diseases. Tumors develop only in tissues whose cells are able to reproduce. Therefore, they do not arise from mature neurons (nerve cells) and cardiomyocytes (heart muscle cells), since these cells have already lost their ability to multiply.

Division of tumors

Tumors can be classified asbenign(benign) andmalignant(this group is often commonly referred to as “cancers”, although this is not medically normal; this will be explained later).

Benign neoplasms are much more common than malignant ones. A neoplasm may be more or less similar to the normal tissue from which it originates in terms of structure and the appearance of its cells. This is called tumor differentiation – it can be assumed that the more similar to normal tissue it is, the less malignant it is. Benign neoplasms are characterized by a very high degree of differentiation.

Tumor development

The medical literature also uses two terms that are directly related to the development of a neoplasm or the transformation (transformation) of a benign change into a neoplasm.

A pre-neoplastic lesion is a lesion that is associated with a greater risk of developing a malignant neoplasm (such a lesion is more likely to develop neoplasm). An example of this type of lesions are colon adenomas (colloquially called polyps; this is not entirely correct nomenclature, as not every polyp is an adenoma), on the basis of whichcolon cancerdevelops .

Pre-cancerous conditionis a disease associated with an increased risk of malignancy. Patients diagnosed with such a disease should undergo careful medical observation and appropriate diagnostic tests should be performed in them, which enables early detection of pre-neoplastic changes or already neoplasms and effective treatment. An example of a precancerous condition is an inflammatory disease of the large intestine calledcolitis ulcerosa, in which there is an increased risk of developing colorectal cancer.

Malignant neoplasms

Malignant neoplasms can be divided into several large groups depending on the tissue from which the first cell that gave rise to the tumor originated. Malignant tumors of epithelial origin (and therefore developing from epithelial cells) are calledcarcinomas,tumorsoriginating from mesenchymal cells aresarcomas(sarcoma) , and tumors of the lymphoid tissue and the hematopoietic systemarelymphomasandleukemias.There are also tumors that originate from the primary sex cell; they usually develop in the gonads (testes and ovaries) and are calledgermline tumors. Moreover, neoplasms of the central nervous system (brain and spinal cord) constitute a separate group.

Dig. 1.Gastric lymphoma in the form of ulceration of the mucosa

Malignant neoplasms are characterized by the presence of several features that make them deserve to be called “malignant” and determine the biological behavior of the described changes. Two main features are the infiltration of adjacent tissues and the ability to metastasize to lymph nodes or distant organs. Infiltration destroys the tissues surrounding the tumor or the organ from which it originates. Cancer cells also have the ability to infiltrate blood and lymph vessels. Thanks to this, after getting into the lumen of the vessel along with blood or lymph, they can spread throughout the body. If, elsewhere, in a distant place, cancer cells find favorable conditions to settle and multiply – they stay there and form a new cancerous tumor called metastasis.

Lymphatic metastases first appear in the lymph nodes closest to the primary tumor. Mainly crayfish is spread this way. On the other hand, metastases related to dissemination through blood vessels can arise anywhere in the body, most often in the lungs, liver and bones. First of all, sarcomas spread through the blood vessel path.

Neoplastic cells can also use the cerebrospinal fluid path to spread – this applies to tumors of the central nervous system, or spread to body cavities (e.g.ovarian cancerinto the pleural or peritoneal cavity) which is usually accompanied by the appearance of fluid in these cavities (e.g.ascites, i.e. fluid in the abdominal cavity). The larger the tumor, the more cells it divides (multiplies) and the more likely it is to metastasize. That is why it is so important to detect malignant neoplasms when their size is not large and effective treatment is possible. Other features of malignant neoplasms that may appear in different combinations in each case are:

• usually rapid growth
• no tumor capsule
• regrowth in the place of original occurrence after inaccurate removal of the first lesion (i.e. local recurrence)
• malignancy characteristics affecting the cells themselves (e.g. the shape and appearance of a cell nucleus)
• high ability to create new, abnormal vessels (i.e. angiogenesis)
• large variation in the appearance of neoplastic cells.

Currently, thanks to the progress of medicine and the diagnostic tests used for this purpose, more and more malignant neoplasms can be detected at an early stage, which enables the cure of patients. In the treatment of cancer patients, special anti-cancer drugs (chemotherapy), radiation (radiotherapy) and surgery are used.

The latest achievement of medicine and at the same time a field that is covered by many ongoing research is the so-called targeted treatment – that is, the use of drugs that target specific, “broken”, abnormal molecules found in cancer cells.

Benign neoplasms

For comparison, the features of benign tumors are:

• sharp demarcation of the tumor (no infiltration of the surrounding tissues, even in the absence of the tumor capsule)
• expanding type of growth
• usually the presence of a bag made of fibrous tissue
• no ability to metastasize.

These types of tumors grow slowly over many years, gradually increasing in size. However, there are exceptions to these rules.Hemangiomas, which are benign tumors made of blood vessels, are not surrounded by the capsule and are pressed with irregular projections between the cells of the organ in which they grow.

The growth rate ofuterine fibroids(i.e. benign tumors made of muscle tissue; these are the most common cancers in women) depends on the action of hormones. Therefore, fibroids can grow rapidly in pregnant women.

Dig. 2.Polyp of the stomach

Dig. 3. Thepolyp of the sigmoid colon (part of the large intestine) visible in virtualcolonoscopy

Some of the benign neoplasms grow as polyps – it only determines the shape of a given lesion, i.e. a pedunculated structure with a round outline, protruding above the surface of a given plane. A malignant neoplasm or an inflammatory lesion may also develop in the form of a polyp.

Colon polyps are changes found during endoscopic examinations (colonoscopy orrectoscopy) for a variety of reasons. They are removed during such examination and thena histopathological examination is performedin order to determine the nature of the lesion (benign or malignant tumor) and to establish further treatment. Most often, the term polyp of the large intestine is understood as benign neoplasms of the mucosa of this section of the gastrointestinal tract, i.e. adenomas (adenomatous polyps) – as mentioned above, these are precancerous changes. They are associated with the risk of developing colorectal cancer and therefore must be removed (this is called a polypectomy) to prevent cancer. This issue is discussed in detail in the chapter on colorectal cancer. In addition to the digestive tract, polypoid lesions can also be found in the upper respiratory tract (nasal cavity, sinuses), in the uterine cavity and in the urinary tract.

Angiogenesis is the process of creating new, tiny blood vessels. This phenomenon occurs in embryonic development, when individual tissues and organs develop, and also after birth. The formation of new vessels is associated with events such as woundhealing, the monthly cycle in women (endometrial regeneration), bone growth, but also with the development of tumors. Then, the newly formed vessels provide blood supply and nutrition to the growing tumor.

Locally malignant neoplasms

In addition to benign and malignant neoplasms, there are also lesions known as locally malignant neoplasms. These are tumors that show some features of malignant neoplasms (mainly the ability to invade and destroy surrounding tissues and organs), but they do not metastasize or look like a benign tumor, but may recur after removal. The most common of this type of tumor is a skin cancer called basal cell carcinoma. Despite its name (cancer), it does not metastasize, although it destroys the tissues in which it grows.

The issue of epithelial neoplasm (ie cancer) at the initial stage of development requires a separate discussion – in relation to such a change the term “non-infiltrating cancer” is used (in Latin in situ, ie at the place of its origin). The word “cancer” means that it is already a malignant tumor, but because it has not yet crossed the epithelial boundaries, it does not infiltrate and damage adjacent tissues. Consequently, it is not yet possible to create metastases. Thus, it is a very early stage of cancer development which, when detected at this stage, is completely curable. In medicine, the term “intraepithelial neoplasia” or “dysplasia” is used to describe this stage of cancer development. Such a lesion is made up of cells that exhibit all the malignant characteristics, both in terms of the appearance of the cells themselves and the structure of the epithelium.

Epithelial dysplasia can be divided into low grade lesions (they do not include full epithelial thickness, the risk of cancer development is low) and high grade lesions (lesions cover the full epithelial thickness, and the risk of developing cancer in this case is very high). In simplified terms, it can be assumed that if all cancers were detected at the stage of intraepithelial neoplasia, it would be possible to cure all cancer patients.

One of the organs in which such early detection of neoplastic changes and preventing their further development is possible is the cervix. Gynecological cytology is the test that enables the detection of dysplasia in the multilayered squamous epithelium covering the shield of the vaginal part of the cervix. It is a simple, cheap, painless procedure, which consists in taking a smear with a special brush from the disc of the vaginal part and the cervical canal (Figure 3 –I suggest a classic scheme of the cervix + maybe removing the cytology brush and the smear itself).

Make sure you have a Pap test regularly as it can prevent the development of advanced cancer.

With regard to the cervix, the terms “dysplasia” and “intraepithelial neoplasia” have been replaced by English terminology. We are talking about lesions of the CIN type (cervical intraepithelial neoplasia, i.e. cervical intraepithelial neoplasia and an abbreviation derived from the first letters of the English name) or SIL (squamous intraepithelial lesion, i.e. an intraepithelial lesion within squamous multilayer epithelium and an abbreviation created analogously). In addition, changes occurring in the cervical epithelium can be graded, as mentioned above, into those that are associated with large (then we are talking about CIN II or CIN III, either in the case of H-SIL smear test [the letter “H” comes from the English word “high” and means a high risk of cancer development]) or with a low risk of cancer development (in this case the term CIN I or L -SIL [likewise the letter “L” stands for the English word “low” and is used to denote a low risk of developing cancer]). The terms dysplasia and intraepithelial neoplasia are also used in relation to changes in the glandular epithelium, e.g. in the stomach and large intestine, and then a similar division into changes with low and high degree of dysplasia is used. For example, a removed adenomatous polyp of the large intestine may contain foci of high or low degree of dysplasia. The terms dysplasia and intraepithelial neoplasia are also used in relation to changes in the glandular epithelium, e.g. in the stomach and large intestine, and then a similar division into changes with low and high degree of dysplasia is used. For example, a removed adenomatous polyp of the large intestine may contain foci of high or low degree of dysplasia. The terms dysplasia and intraepithelial neoplasia are also used in relation to changes in the glandular epithelium, e.g. in the stomach and large intestine, and then a similar division into changes with low and high degree of dysplasia is used. For example, a removed adenomatous polyp of the large intestine may contain foci of high or low degree of dysplasia.