Cancer

What is Cancer?

Cancer refers to the uncontrolled growth of cells, which grow independently and arrange themselves abnormally without performing any function. Random DNA mutations are known to cause most types of cancer. However, not all cell types in a tumor are the same. A small fraction, about 1%, consists of cancer stem cells (CSCs). CSCs are very similar to normal stem cells in the human body, as they are pluripotent and can self-renew. It is these cells that help cancer spread throughout the body and divide and differentiate to form new tumor cells. According to the reports published by WHO, cancer is the second leading cause of death in the world.

Types of Cancer

Based on the tissue of origin, cancers are classified as follows: 

Carcinoma: Carcinoma refers to cancer of epithelial tissue origin. Epithelial tissue is the covering of any organ that faces the external or internal environment, such as the skin, the lining of the intestine, the oral lining, or the lining of the nose. They are the most informed type. Some examples of carcinomas include prostate cancer, breast cancer, and squamous cell carcinoma of the skin. 

Sarcomas: These are malignant neoplasms of connective tissue origin. Connective tissue supports and connects different parts of the body. For example, cancer of adipose tissue, areolar tissue, tendons, ligaments, and bones. 

Leukemia: Leukaemia is a blood cancer that results from the uncontrolled growth of white blood cells. The four main types of leukemia are lymphocytic (acute and chronic) and myeloid (acute and chronic). The terms lymphocytic and myeloid leukemia refer to cancer cells that are in different stages of maturation to form white blood cells in the bone marrow. 

Lymphoma: These are cancers of the lymph nodes and lymphatic organs. Lymph refers to the fluid that builds up within the interstitial spaces. It has its distinct network of lymphatic vessels and small clusters of lymph nodes in many areas of the body. Lymph contains lymphocytes, which help fight infection. There are two types of cancer, or lymphoma, in these areas: Hodgkin’s and non-Hodgkin’s lymphoma.

According to the organ or tissue cancer has been classified as follows:

1. Breast cancer
2. Cervical Cancer
3. Oral cancer
4. Prostate cancer
5. Uterine cancer
6. Ovarian cancer
7. Blood cancer
8. Lung cancer
9. Stomach cancer
10. Bone cancer
11. Colorectal cancer
12. Throat cancer
13. Liver cancer
14. Skin cancer
15. Bladder cancer
16. Brain cancer
17. Kidney cancer
18. Testicular cancer
19. Pancreatic cancer
20. Endometrial cancer
21. Vaginal cancer

Cancer staging 

Cancer staging can be determined by evaluating the cancerous tissue. 

‘Grading’ and ‘staging’ are two methods of predicting tumor behavior and assisting in treatment planning after a malignancy has been detected. The classification is histological, that is, the tissues are studied under a microscope, while the staging is clinical and is detected by a simple examination. After examining the tissue under a staging microscope, the cancer is staged. 

A microscopic image of cancerous tissue provides information about two things: 

1. the rate of growth of cancer compared to healthy cells, 
2. the structure (degree of anaplasia) of the cancer cells. 

Cancer is said to be benign when a significant amount of cell growth is seen in a particular area. When cancer cells have spread and are not located in a particular area, it is called metastasis. 

The Broder classification system classifies cancer cells based on the degree of differentiation of the cells, from most differentiated, which refers to cells that appear normal and spread gradually, to less differentiated cells, which are cells that look normal. very different from what they are. They originally appeared. 

These grades are: 

Grade I: well-differentiated 

Grade II: moderately differentiated 

Grade III: moderately differentiated 

Grade IV: poorly differentiated 

A Pathologic examination, laboratory tests, and clinical examination of a sample containing cancerous tissue are used to establish the cutoff. 

Because the tumor has spread. TNM staging and American Joint Committee (AJC) staging are the two most important staging methods currently used to determine the stage and grade of cancer. 

TNM Staging Staging: TNM has 3 components, where T refers to the primary tumor, N is for regional lymph node involvement, and M is for distant metastases. All three components have numbers listed to indicate the extent of involvement: 

T0: No tumor found 

T1-3: Numbers 1-3 indicate tumor size in ascending order, meaning the larger the number, the larger it will be. The size of the tumor and the spread to its surrounding structures. 

N0: Lymph nodes are not affected. 

N1 to N3: Show the extent of lymph node involvement about the size, location, and the number of affected lymph nodes. Again, the higher the number, the greater the number of lymph nodes. 

M0 – no metastases spread to other sites. 

M1– There is a spread of the tumor to other sites.

Symptoms of Cancer

Cancer symptoms vary greatly, depending on the affected area. Some specific signs and symptoms that may be experienced regardless of the type and size of cancer: 

• Unusual weight gain 
• Weakness and fatigue 
• Frequent bruising of the skin 
• The feeling of a lump under the skin 
• Shortness of breath and more than a month 
• Prolonged cough 
• Skin changes, such as changes in the size and shape of existing warts or sores 
• Easy bruising of the skin 
• Digestive problems such as diarrhea or constipation 
• Difficulty swallowing 
• Loss of appetite 
• Changes in voice quality 
• Frequent episodes of fever or night sweats 
• Muscle or joint pain and delayed wound healing 
• Recurring infections 

If you notice any of these symptoms, you must talk to your doctor because it is best to control cancer as soon as possible. 

You should also keep in mind that not all of these symptoms are seen in everyone and not everyone experiences them acutely in the later stage. Some people may not have any symptoms until a simple exam clearly shows cancer. Therefore, you mustn’t ignore even the slightest symptoms.

Causes of the Cancer

Cancer occurs as a result of some change or mutation in the DNA of cells. DNA, which is considered the brain of the cell, gives instructions on cell growth and multiplication. Errors in these instructions can lead to cancer due to uncontrolled growth and multiplication. Substances that can cause cancer to develop are called carcinogens and, along with other risk factors, are the main cause of cancer. They can be chemicals, for example, found in tobacco smoke; physical, such as ultraviolet radiation; or biological, such as the human papillomavirus. No single carcinogen can be held responsible for causing cancer. Various carcinogens, along with other factors such as health and diet, cause cancer to develop in a person.

Risk Factors of the Cancer

The most common risk factors for cancer are: 

• Dependence on tobacco and tobacco-related products, such as smoking or chewing, causes lung and oral cancer. 
• Excessive alcohol consumption increases the risk of liver cancer in many others. 
• An unhealthy diet and consumption of low-fiber refined foods lead to colon cancer. 
• Elevated levels of hormones, such as testosterone and estrogen, are risk factors for developing prostate cancer and breast cancer, respectively. 
• Increasing age increases the chances of developing certain types of cancer, such as colon cancer, breast cancer, prostate cancer, and many others. 
• Genetic defects or mutations significantly increase the chance of cancer, for example, women with mutations in the BRCA1 and BRCA2 genes are at risk of developing breast cancer. 
• A positive family history increases the risk of certain types of cancer, such as breast cancer. 
• Occupational hazards, such as exposure to chemicals such as dyes, tars, and aniline, increase the risk of certain types of cancer, such as bladder cancer. 
• Bacterial and viral infections cause systemic disorders, which act as a predisposing factor for cancer, for example, H. pylori infection can lead to the development of colon cancer; Hepatitis B and C infection can lead to liver cancer, and human papillomavirus infection can lead to cervical cancer. 
• Excessive exposure to radiation from repeated X-rays or harmful ultraviolet rays from sunlight also increases the risk of developing cancer. 
• Obesity, high fat intake, and limited physical activity are important risk factors for the development of various types of cancer in both men and women. 
• Due to its far-reaching effects, stress is considered a major risk factor for cancer. Also, weakened immunity due to past or current medical conditions increases a person’s susceptibility to cancer. 

As you can see, most of these risk factors, in addition to being genetic or age-dependent, can be avoided with a healthy lifestyle and adequate protection against infections and pollutants. If you have a positive family history or are generally at high risk for any type of cancer, you must make the desired lifestyle changes to reduce your risk.

Prevention of Cancer

It is possible to prevent most types of cancer by adopting a healthy lifestyle and controlling risk factors. 

Here’s what you can do to get better: 

• Avoid smoking. 
• Limit your alcohol intake. 
• Avoid excessive exposure to sunlight. 
• Take a diet rich in fiber. 
• Avoid consuming too much fat in your diet and stay away from sources of red meat such as pork and beef. 
• Also, limit your intake of processed foods in your diet. 
• Limit radiation exposure by wearing protective equipment in case of occupational exposure. 
• Get regular exercise and maintain a healthy weight and BMI. 
• Take a healthy and balanced diet. 
• Go for regular check-ups and tests to detect abnormalities or to identify the disease at an early stage. 
• Consult a doctor in case of long-term problem or unhealing injury or severe skin injury. 
• Go for regular vaccinations. 

Human papillomavirus (HPV) vaccine helps prevent cervical cancer and is essential. Another vaccine to consider is the hepatitis B vaccine, which prevents infection with the hepatitis B virus, a known risk factor for liver cancer. Identify ways to deal with stress. Spend time with family and friends, find a hobby, practice yoga or meditation, play a sport, or do other things that help calm your mind.

Methods to Diagnose Cancer

When choosing a diagnostic test, the doctor will consider the person’s age, medical history, gender, family history, the type of cancer suspected, the severity of symptoms experienced, and past test results. 

The most common diagnostic tools used to determine the likelihood of cancer are the following: 

• Physical examination to look for abnormalities. 
• Laboratory evaluation of the person’s blood sample (complete blood count, ESR test, C-reactive protein test, liver function test, kidney function test, and more). 
• Your doctor may recommend specific tests such as cancer antigen 19.9 (CA 19.9), carcinoembryonic antigen (CEA), or prostate-specific antigen (PSA) when cancer of specific origin is suspected. 
• Imaging techniques such as X-ray, CT scan, MRI, barium flour study, bone densitometry, PET scan, SPECT scan, USG, etc. may also be recommended. Tissue biopsies collected from suspected tumors will be examined under a microscope to identify the stage of the tumor, the severity of its growth, and the type of tumor cells.

Treatment of Cancer

There are mainly two types of cancer treatment options: 

1. Surgical methods involve the removal of abnormal growths or masses of cells, followed by a biopsy of the removed area. This is particularly useful when the tumor is accessible and localized. 
2. Non-surgical methods are chemotherapy, which consists of drugs to destroy abnormally growing masses of cells, and radiotherapy, which uses radiation such as gamma rays directed at the growing tumor. 

Sometimes both surgical and non-surgical methods are used. 

Radiotherapy or chemotherapy is first recommended to reduce the size of the tumor and then to excision of the cancerous lesion. After surgery, chemotherapy or radiotherapy is administered to the area again to prevent the lesion from progressing to other sites. 

Other treatment options are hormone therapy, immunological treatments, bisphosphonates, etc. 

These are used according to the needs of specific cancer. eg. Breast and prostate cancer can be treated with hormonal therapy. 

Medicines are also prescribed to control the associated symptoms of cancer. These may include pain relievers, antacids, and fever-reducing drugs to control individual symptoms. 

Palliative care is often the only possible treatment, with the use of morphine patches or other pain relievers to relieve pain and discomfort caused by cancer, as cancer cannot be controlled due to its generalized nature. 

New treatments 

The field of oncology is rapidly emerging. Almost every year, new treatments are introduced to reduce costs and prevent cancer recurrence. Cancer recurrence rates range from seven to nearly 100 percent, depending on the type. The latest research focuses on finding ways to understand how cancer cells work to find the best possible ways to stop their growth and spread. This includes studies on cancer stem cells for the identification of CSC markers and the development of specific T cells to target and eliminates CSCs to discover specific DNA mutations and genetics behind cancer development.

Prognosis 

The outcome of cancer depends on its type. Small-sized or early-stage cancers are easier to treat and therefore have an excellent prognosis. On the other hand, the outcome for metastatic lesions is poor, as dissemination cannot be completely stopped and may lead to multiple system failures or other complications. In addition, the prognosis also depends on the type of tumor cells and the area of ​​the body affected.

Complications 

The severity of complications also depends on the part of the body affected. Metastatic tumors pose a far greater risk than those that have not spread. Complications depending on the organ systems affected include: 

• Heart failure 
• Pulmonary edema (retention of fluid in the lungs) 
• Liver failure 
• Kidney failure 
• Repeated infections due to poor immunity

Conclusion

Cancer is a large group of diseases and this is characterized by abnormal growth of cells that form a tumor (mass or lump of tissue). Cancer can affect cells in any organ or tissue in the body and can actively divide and spread to different sites in the body or continue to grow in one place. Depending on this characteristic, tumors can be benign (those that do not spread) or malignant (those that do spread). The causes of various types of cancer vary, however, some of the most common causes of cancer are genetic mutations, stress, smoking, alcohol, low-fiber diets, exposure to chemicals or radiation, and so on. The diagnosis is determined by physical examination, X-ray, CT scan, MRI, and positron emission tomography. Cancer can be largely prevented by avoiding its causes and risk factors. Treatment includes single or multiple methods, such as chemotherapy, radiation therapy, and surgery. Full cure is possible for certain types of cancer if it is detected early and treated immediately. Although this is not always possible, there are several treatment options to limit its spread and reduce complications so that a person’s life will be comfortable.

(Disclaimer: Information provided in this piece of article is purely for educational purposes only. All results must be clinically correlated with the patient’s data to make an accurate diagnosis.) 

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References

1. Textbook of Pathology : Harsh Mohan (Google Book)
2. National Cancer Institute.  Risk factors for cancer. 
3. American Cancer Society. What causes cancer? 
4. American Cancer Society. Cancer staging.