Introduction to CANCER
Cancer is a complex and life-threatening group of diseases that is characterized by the uncontrolled, abnormal growth and spread of cells in the body. According to the World Health Organization (WHO), cancer is one leading causes of death worldwide. More than 10 million deaths in the year 2020 have resulted due to cancer. Cancer can develop in any part of the body in people of all ages. Cancer cells divide and grow uncontrollably to form a tissue mass called a tumor. A tumor can be benign or malignant. Benign tumors are non-cancerous and they do not spread to other parts of the body, while malignant tumors are cancerous and they have the potential to invade the nearby tissues and organs or spread to other parts of the body. Cancer spreading to the nearby tissues or organs can occur through the bloodstream or lymphatic system. This process is known as metastasis. The benign and malignant natures are described by specific features and characteristics of the tumor. Early detection and effective treatments are the most crucial factors in reducing the mortality and morbidity associated with cancers. WHO established some strategies such as cancer screening programs, vaccination for certain cancer types, and access to quality cancer care to improve cancer outcomes and reduce the global burden of the disease.
Cancers can be classified in many different ways. Depending on the type of cancer, the characteristics, symptoms and treatment options available may differ. As mentioned earlier, the cancer classification can be done based on the affected tissue or organ, the type of cells involved and the extent of the disease. There are many different types of cancers according to the classification system related to the affected tissue or organ where cancer originates, such as lung cancer, breast cancer, prostate cancer, colon cancer, leukaemia etc. These are classified according to the affected region of interest or the system of the body. Cancers can be categorized based on the cells involved in the tumor. Carcinomas are cancers induced in epithelial cells; the cells that line the body’s internal and external surfaces. Sarcomas are the cancers that start in connective tissue cells; such as in bones, cartilage or muscles. The cancers that start in blood-forming cells are called leukaemia and they mainly affect the bone marrow and blood. Lymphomas are cancers which form in the lymphocytes, the immune system cells in lymph nodes, spleen etc. Another method of cancer classification is by the stage and the grade of cancer. The cancers can be classified based on the extent of the disease. For instance, stage 0 is carcinoma in situ and stage I to stage IV represent the more advanced cancer stages respectively. Further, the grade of cancer also can be taken as a classification mode. There, it stages the cancers based on the abnormal nature of cancer cells in a microscopic view. In this system, the cancers are graded from well-differentiated low-grades to poorly differentiated high-grade cancers. Moreover, with advances in technology and research, cancer classification can be done based on molecular characteristics such as genetic mutations or protein expression patterns. This is a valuable cancer categorizing method which will help to guide the treatments and prognosis predictions accurately. The importance of these classification systems is to help healthcare officers to determine the best treatment options available for individuals based on the nature of the disease state.
Signs and Symptoms of Cancer
The signs and symptoms associated with cancers can vary depending on the type and stage of cancer. Sometimes, cancer patients may not experience any symptoms related to cancer while some may have a range of symptoms from mild to severe. Some common symptoms of cancer include fatigue; unexplained tiredness or fatigue which doesn’t pass away with rest, pain that doesn’t go away with treatments, changes in bowel or bladder habits such as melena; hematuria, unexplained weight loss, skin changes such as darkening; yellowing; or redness, persistent cough or hoarseness or swelling or lumps in the neck; under arm; or groin. Depending on the type of cancer, some may have one of these symptoms, some may have combinations of these symptoms. While some may not have any of these as symptoms. Thus, it is necessary to accurately identify the signs and symptoms associated with cancers to improve the outcomes and to increase the chance of a cure.
Etiologies of Cancer
The cancers may have a wide variety of etiological causes. Some of them are genetic mutations, environmental factors; such as exposure to tobacco smoke; exposure to radiation, and lifestyle factors. Some cancers arise due to inherited genetic mutations or changes in the DNA of normal cells and they are having an increased risk of developing life-threatening cancer. Breast and ovarian cancers are cancers that resulted from BRCA gene mutations. Exposure to environmental toxins and carcinogens also increases the potential for developing cancer. For example, excessive exposure to tobacco smoke, ultraviolet (UV) radiation from the sun, ionizing radiation, and certain chemicals and pollutants may cause cancers. Not only that, but also some factors related to lifestyle may induce the risks for cancers such as excessive usage of tobacco; alcohol consumption, obtain diet high in processed and red meat, and lack of physical activity. Some cancers can be resulted due to infections from certain viruses and bacteria. The most straightforward clues for this fact are the link and association between Helicobacter pylori and stomach cancer, Human Papilloma Virus (HIV) and cervical cancers and Hepatitis B and liver cancers. Moreover, Aging and hormonal factors may also have some association with cancer induction. Sometimes cancers can result from a combination of multiple factors. Therefore, it may more important to investigate the specific cause attribute of cancer before proceeding with the treatments, as it will lead to a more accurate prognosis, diagnosis as well as treatments.
Cancer treatments depend on the type and stage of cancer, as well as the patient’s overall health and preferences. Some of common cancer treatments include surgery, radiation therapy, chemotherapy, targeted therapy and hormone therapy. Surgery in cancer treatments involves the removal of the tumor along with the surrounding tissues. Usually, this is used for solid cancers and this is a much more effective treatment mode for early-stage cancers. Radiation therapy uses high-energy radiation to kill cancer cells while chemotherapy; uses drugs to kill the cancer cells. Targeted therapy involves the use of drugs or other substances that target specific proteins or genes in cancer cells to block the growth of cancer cells and to signal the immune system to attack the cancer cells. Hormone therapy, blocks or lowers the level of hormones in the body that promote the growth of cancer. This is effective for hormone-sensitive cancers. Additionally, stem cells transplant can be done as a cancer treatment option. This involves the replacement of damaged or destroyed bone marrow with healthy stem cells. This is a widely used treatment mode for blood-related cancers, such as leukaemia and lymphoma. Though cancer treatments are effective in controlling cancers, there are many side effects associated with them. Therefore, it is necessary to determine the best treatment option available for individuals according to their special situations.