What is Cancer and Types of Cancer?
What is Cancer and Types of Cancer?
For the average person, a cancer diagnosis sounds like a sentence. The disease is very different. Some of its types are easily detected and effectively treated. Others are rare and difficult to define, but they will hit for sure if they show up.
Science classifies cancers depending on which system or organ they affect. In domestic medicine, cancer is only carcinoma, a malignant tumor of the epithelial cells of internal organs. Best cancer specialist in Pakistan which treat patients at their state of the art cancer center with special infusion suites for chemotherapy. Each suite is private, safe and comfortable.
The very name of the disease appeared when the ancient sage Hippocrates, studying the causes of death of some of his compatriots, cut the affected organ and decided that the tumor found there reminded him of cancer (in Greek – karkinos). Later, the ancient Roman physician Cornelius Celsus translated the term into Latin: cancer.
Other types of ailment that do not affect the epithelium are called differently: sarcoma appears in the muscles, bones and connective tissue, lymphoma affects lymph, and so on.
Blood cancer, brain cancer – these are common but imprecise, philistine terms.
There are several dozen types of malignant tumors, if we classify them by the affected organs and tissues. But only 12 types of cancer make up almost 70% of all oncological diseases in Pakistan.
Fortunately, the most common doesn’t mean the deadliest. Let’s talk about the first and the second, focusing on three parameters:
1. How many people are registered in oncological dispensaries in Pakistan?
2. How often a particular type of cancer causes death.
3. What are the risks of dying from a specific disease in a certain period, for example, a year? This rate is called mortality.
Breast cancer:
Lumps in the breasts are common and are caused by many factors, including tumors. In most cases, neoplasms appear in the mammary glands’ lobules (the cells responsible for the formation of milk) and the ducts that connect the lobules to the nipples.
Therefore, doctors recommend that women regularly conduct self-examination by feeling their breasts with their fingers. Any seal is a signal that you should consult a mammologist.
The mammary gland cells, like all others, use receptors to send chemical signals to trigger the desired cellular reactions. How the receptors behave can help identify the type of breast cancer and find the most effective treatment.
Estrogen-dependent tumors:
Normal cells of the mammary glands and some cancer cells contain receptors that can capture and attract estrogen and progesterone. Getting hormonal support, the tumor grows.
Those cancers that are formed by such cells respond well to hormone therapy. Certain drugs block receptors that take estrogen and progesterone, hormones stop entering cells, and the tumor stops growing.
HER2-positive tumors:
Other receptors that accept the HER2 protein (epidermal growth factor receptor) also stimulate cell development. The HER2-positive cancer subtype is less common but more aggressive than estrogen-dependent cancers. However, it can also be affected by certain drugs that block the HER2 protein.
In oncology, sensitivity is a good indicator. The more sensitive the neoplasm, the better the body will respond to treatment.
Three times negative subtype:
If a tumor does not have any of the receptors listed above, it is called triple negative. This is the rarest of the listed types of neoplasms. These tumors spread quickly and are difficult to treat. They are more common in women with a mutation in the BRCA1 gene that inhibits cancer cells’ growth.
Skin cancer
Melanoma is not the most common, but the most dangerous type of skin cancer. In this case, a malignant tumor grows and metastasizes at a tremendous rate.
Other, non-melanoma cancers (basal cell and squamous cell) are much more common, but less dangerous, better treatable, and generally have better survival rates.
The best way to recognize skin cancer early is to look for new or discolored or shaped skin lesions. You need to be especially careful about moles that are unlike others or that have changed their outlines.
These signs should prompt you to consult a doctor (dermatologist or oncologist):
- Asymmetry (one half of the mole does not match the size of the other);
- Rough edges (rough, blurry, jagged);
- Color not like others, interspersed with yellow, brown or black in a single mole;
- Diameter over 6 mm;
- Any changes in size, color, shape.
Superficial spreading melanoma
The most common form of melanoma (about 70% of cases). It looks like a flat or slightly convex area of skin with fuzzy, uneven borders that has changed color. May appear at the site of moles.
Lentiginous melanoma
It is similar to the previous type and is formed close to the skin’s surface, often from age spots. It occurs in the elderly and those who spend a lot of time in the sun.
Acrolentiginous melanoma
It appears as a black or brown spot under the nails, on the soles, palms.
Nodular melanoma
A very aggressive form. By the time of detection, the cancer has already penetrated deep into nearby tissues as a rule. This process is called invasion.
Prostate cancer:
Early diagnosis of prostate cancer can be life-saving. But early detection raises a tricky question: Which is scarier – the disease or the side effects of treatment?
The fact is that many prostate tumors develop very slowly and for years, or even decades, may not cause serious problems. However, treatment sometimes leads to unwanted side effects, including incontinence and impotence.
To not miss the development of this type of cancer, all men after 50 years of age are advised to consult a doctor and begin an annual examination of the prostate. And if oncological diseases were found in the closest relatives, it is advisable to start regular examinations at the age of 45.
Adenocarcinoma:
More than 95% of all malignant tumors of the prostate gland are adenocarcinomas that form from the epithelium of the gland (the root “adeno” means “gland” in Greek). But within this category, neoplastic cells take different forms. The WHO classification describes the options: from swollen cells, colloidal, cricoid (nuclei are displaced to the periphery, so the cells look like rings with stones). And that’s not all types.
Oncologists use the Gleason classification based on differentiation (i.e., the degree of maturation) of cells.
The less differentiated the tumor cells, the more complex the form of cancer. The fifth grade is assigned to such neoplasms: they are dangerous and spread quickly. Well-differentiated cells receive the first grade. They look almost healthy.
Small cell carcinoma
A rare and aggressive form of prostate cancer that is difficult to detect. Unlike adenocarcinomas, it does not release the signaling marker protein, prostate-specific antigen (PSA), usually found in a blood test. The tumor consists of small round cells, hence the name.
Squamous cell carcinoma
This type of prostate cancer is not related to glandular tissue. Squamous cell carcinoma affects the tissues of the prostate’s squamous epithelium, and since PSA levels do not increase, it is difficult to detect it. Carcinoma is very aggressive, the average life expectancy after its detection is just over a year. Fortunately, it is rare: less than 1% of all cases of prostate cancer.
Kidney cancer
Almost all cancers begin in the epithelium of the nephrons’ tubules, which are the main cells of the kidneys. Unfortunately, at an early stage, the disease practically does not manifest itself. As we have cancer Dr in Lahore they are specialists of oncologist and detect tumor on an ultrasound of the kidney if it is prescribed for some reason.
As the cancer progresses, symptoms appear. They usually include blood in the urine (it may be present or disappear), pain in the abdominal region, and a lump in the kidney area that can be felt.
Kidney cancer has long been considered insensitive to chemotherapy, but researchers are gaining more success with drug treatments. Until recently, any kidney cancer was classified as renal cell carcinoma. Now the disease has been divided into subcategories.
Clear cell kidney cancer
The most common type, it accounts for up to 85% of cases. It is difficult to diagnose it early on.
Papillary renal cancer
This category, in turn, is divided into two subtypes. The first accounts for up to 5% of all kidney cancer cases, the second – up to 10%. They differ in the size of the affected cells and the risk of metastases: in the first case, these cells are small, in the second – large, and often lead to metastasis to other organs.
The first subtype is often hereditary. A mitogen (a gene that causes a tumor) is passed from parents through germ cells – gametocytes.
Thyroid cancer
Thyroid cancer responds well to treatment. Sometimes it is found after the appearance of a lump on the throat (this is how the enlarged thyroid gland makes itself felt), sometimes when the patient complains of difficulty swallowing, breathing, or manifested hoarseness.
Only 5% of thyroid tumors develop aggressively and threaten other organs.
Many neoplasms grow so slowly that recently they have even ceased to be considered malignant.
Most thyroid tumors do not respond to chemotherapy, but some new developments are encouraging. For example, kinase inhibitors help block an enzyme present in the formation cells. They also inhibit the growth of new blood vessels.
Differentiated tumors
About 90% of thyroid cancers are highly differentiated tumors. They are subdivided into subgroups: papillary, follicular. They are more common in women and young people and have favorable prognosis.
Medullary cancer
Sometimes it is caused by the inheritance of a mutation in the RET proto-oncogene. Patients with this condition are often advised to remove the thyroid gland. Otherwise, the chances of successful treatment are greatly reduced.
Anaplastic cancer
The most aggressive type of thyroid carcinoma. Such neoplasms grow rapidly, respond poorly to treatment and actively metastasize to other organs.
Lymphoma:
Lymphoma is any malignant process that begins in the lymphatic system. The lymph nodes are often affected – small oval organs that cleanse the body of debris such as viruses, bacteria, and cancer cells. The nodes are connected by vessels through which not blood flows, but lymph. It is a liquid containing white blood cells called lymphocytes.
The lymphatic system removes fluid and waste products from the bloodstream. Lymphomas weaken the immune system and increase the risk of infections.
If you have swollen lymph nodes, see your doctor as soon as possible. This does not have to be lymphoma: other diseases can manifest in this way.
The lymphatic and circulatory systems are interconnected and permeate the entire body. These are the pathways that cancer uses to spread metastases.
The lymphatic system is complex, so lymphomas are complex diseases. There are many of their categories and subcategories, significantly different from each other.
Hodgkin’s lymphoma:
It starts with lymphocytes. The most common form is the classic form of Hodgkin’s lymphoma, which is characterized by giant lymphocytes’ appearance. They are called Reed – Berezovsky – Sternberg cells. In 5% of cases, malignant cells are histiocytes, similar in appearance to popcorn.
Most cancer cells are sensitive to DNA destruction. This is what chemotherapy is aimed at.
With the help of special substances, doctors destroy DNA strands. Affected cells cannot multiply and die.
The first chemotherapy for Hodgkin’s lymphoma treatment, approved by the FDA (US Food and Drug Administration), was carried out in 1949. Used nitroiprite – an analogue of the chemical warfare agent mustard gas.
Other drugs are used in chemotherapy today. Moreover, they are used successfully: according to statistics, 9 out of every 10 people recover.
Non-Hodgkin lymphomas:
These forms are much more varied. Many subgroups are more aggressive than the Hodgkin form. If the cells stick together, the lymphoma is called follicular (from the Latin folliculus – “sac”). Cancer cells can spread within the lymphatic tissue evenly, without clumping together. In this case, it is said that the lymphoma develops diffusely.
A promising new treatment for non-Hodgkin’s lymphomas is based on the use of T cells. These are immune cells that are present in the blood. Geneticists work on them in laboratories to place special chimeric antigen receptors (CARs) on their surfaces. These CAR-T lymphocytes can recognize proteins by which tumor cells hide from the patient’s immune system. This is a fundamental principle of immunotherapy in general: to identify cancer so that the immune system can attack it.
Bladder cancer:
Blood in the urine is a characteristic and often the first symptom of bladder cancer. This occurs in 8 out of 10 cases of the disease, most often affecting men.
Bladder cancer often spreads to other parts of the urinary system, including the kidneys, ureters, and urethra.
About 95% of bladder cancers develop in the cells that line the organ from the inside. These cells – urothelium – are constantly in contact with urine and, more importantly, with substances that it removes from the body, and these are carcinogens. For example, chemical compounds in tobacco smoke or exhaust fumes can trigger the development of malignant neoplasms.
This type of cancer quickly adapts to medications. Therefore, it is important to choose new treatments. For example, one of them – gene therapy – uses modified viruses that specifically target tumors of the bladder. As a result, cancer cells are labelled with a hormone that signals the immune system: here is the danger, this cell must be attacked and destroyed.