Dr Bharat Chauhan, medical oncologist at Bombay Hospital and Nanavati Hospital talks about the feared c-word, its causes and treatment
Cancer is not a disease but a syndrome which is characterized by uncontrolled cell growth. There are over 100 different types of cancer, and each is classified by the type of cell that is initially affected. Cancer harms the body when altered cells divide uncontrollably to form lumps or masses of tissue called tumors (except in the case of leukemia where cancer prohibits normal blood function by abnormal cell division in the blood stream). Tumors can grow and interfere with the digestive, nervous, respiratory, endocrine and circulatory systems and they can release hormones that alter body function. Cancer is becoming an epidemic in our country due to change in environment and lifestyle.
Facts on cancer:
- Cancer is considered to be one of the leading causes of morbidity and mortality worldwide.
- Screening can locate cervical cancer, colorectal cancer, Lung cancer and breast cancer at an early, treatable stage.
- The most common sites of cancer among men are lung, prostate, colon, rectum, stomach and liver.
- The most common sites of cancer among women are breast, colon, rectum, lung, cervix and stomach.
Causes of cancer
Cancer is ultimately the result of cells that uncontrollably grow and do not die. Normal cells in the body follow an orderly path of growth, division, and death. Programmed cell death is called apoptosis, and when this process breaks down, cancer begins to form. Unlike regular cells, cancer cells do not experience programmatic death and instead continue to grow and divide. This leads to a mass of abnormal cells that grows out of control. The crux of causation of cancer lies in the genome which gets mutated by the environment and leads to cancer formation.
Cancer and other medical factors
- As we age, there is an increase in the number of possible cancer-causing mutations in our DNA. This makes age an important risk factor for cancer.
- Several viruses have also been linked to cancer such as: human papillomavirus (a cause of cervical cancer), hepatitis B and C (causes of liver cancer), and Epstein-Barr virus (a cause of some childhood cancers). Human immunodeficiency virus (HIV) – and anything else that suppresses or weakens the immune system – inhibits the body’s ability to fight infections and increases the chance of developing cancer.
- Obesity is also implicated in the causation of various cancers like cancer pancreas, cancer colon and cancer breast.
- Addictions like smoking can lead to oral and lung cancers whereas alcoholics are more susceptible for the development of liver cancers.
Cancer stages and diagnosis for cancer
Early detection of cancer can greatly improve the odds of successful treatment and survival. Symptoms guide us regarding the procedures for diagnoses of cancer.
- Imaging techniques such as X-rays, CT scans, MRI scans, PET scans, and ultrasound scans are used regularly in order to detect where a tumor is located and what organs may be affected by it.
- Extracting cancer cells and looking at them under a microscope is the only absolute way to diagnose cancer. This procedure is called a biopsy. Other types of molecular diagnostic tests are frequently employed as well. Physicians will analyze your body’s sugars, fats, proteins, and DNA at the molecular level. For example, cancerous prostate cells release a higher level of a chemical called PSA (prostate-specific antigen) into the bloodstream that can be detected by a blood test. Molecular diagnostics, biopsies, and imaging techniques are all used together to diagnose cancer.
Symptoms of cancer
- A lump on the breast or testicle can be an indicator of cancer in those locations.
- Skin cancer (melanoma) is often noted by a change in a wart or mole on the skin
- Oral cancers present white patches inside the mouth or white spots on the tongue.
- Brain tumors tend to present symptoms early in the disease as they affect important cognitive functions
- Pancreas cancers are usually too small to cause symptoms until they cause pain by pushing against nearby nerves or interfere with liver function to cause a yellowing of the skin and eyes called jaundice. Symptoms also can be created as a tumor grows and pushes against organs and blood vessels
- Colon cancers lead to symptoms such as constipation, diarrhea, and changes in stool size
- Bladder or prostate cancers cause changes in bladder function such as more frequent urination or infrequent urination.
- Coughing and hoarseness can point to lung or throat cancer as well as several other conditions.
Treatments for cancer
Cancer treatment depends on the type of cancer, the stage of the cancer (how much it has spread), age, health status, and additional personal characteristics. There is no single treatment for cancer, and patients often receive a combination of therapies and palliative care. Treatments usually fall into one of the following categories: surgery, radiation, chemotherapy, immunotherapy, hormone therapy, or gene therapy.
Surgery is the oldest known treatment for cancer. If a cancer has not metastasized, it is possible to completely cure a patient by surgically removing the cancer from the body. This is often seen in the removal of the prostate or a breast or testicle. After the disease has spread, however, it is nearly impossible to remove all of the cancer cells. Surgery may also be instrumental in helping to control symptoms such as bowel obstruction or spinal cord compression.
Radiation treatment, also known as radiotherapy, destroys cancer by focusing high-energy rays on the cancer cells. This causes damage to the molecules that make up the cancer cells and leads them to commit suicide. Radiotherapy is used as a standalone treatment to shrink a tumor or destroy cancer cells (including those associated with leukemia and lymphoma), and it is also used in combination with other cancer treatments.
These treatments target any rapidly dividing cells (not necessarily just cancer cells), but normal cells usually can recover from any chemical-induced damage while cancer cells cannot. Chemotherapy is generally used to treat cancer that has spread or metastasized because the medicines travel throughout the entire body. It is a necessary treatment for some forms of leukemia and lymphoma. Chemotherapy treatment occurs in cycles so the body has time to heal between doses. However, there are still common side effects such as hair loss, nausea, fatigue, and vomiting. Combination therapies often include multiple types of chemotherapy or chemotherapy combined with other treatment options.
Immunotherapy aims to get the body’s immune system to fight the tumor. Local immunotherapy injects a treatment into an affected area, for example, to cause inflammation that causes a tumor to shrink. Systemic immunotherapy treats the whole body by administering an agent such as the protein interferon alpha that can shrink tumors. Immunotherapy can also be considered non-specific if it improves cancer-fighting abilities by stimulating the entire immune system, and it can be considered targeted if the treatment specifically tells the immune system to destroy cancer cells. These therapies are relatively young, but researchers have had success with treatments that introduce antibodies to the body that inhibit the growth of breast cancer cells. Bone marrow transplantation (hematopoetic stem cell transplantation) can also be considered immunotherapy because the donor’s immune cells will often attack the tumor or cancer cells that are present in the host.
5) Hormone therapy
Several cancers have been linked to some types of hormones, most notably breast and prostate cancer. Hormone therapy is designed to alter hormone production in the body so that cancer cells stop growing or are killed completely. Breast cancer hormone therapies often focus on reducing estrogen levels (a common drug for this is tamoxifen) and prostate cancer hormone therapies often focus on reducing testosterone levels. In addition, some leukemia and lymphoma cases can be treated with the hormone cortisone.
6) Gene therapy
The goal of gene therapy is to replace damaged genes with ones that work to address a root cause of cancer: damage to DNA. Gene therapy is a very young field and has not yet resulted in any successful treatments.
7) Targeted therapy
It involves the use of various antibodies against specific targets present on the tumor cells. This therapy is devoid of usual side effects of chemotherapy with greater efficacy. Various examples like the trastuzumab in breast cancer and rituximab in lymphoma has revolutionized the management of these cancers.
Prevention for cancer
- To avoid tobacco, limiting alcohol intake
- Limiting UV ray exposure from the sun and tanning beds
- To maintain a healthy diet, level of fitness and seeking regular medical care. Low in fat and rich in fresh fruits and vegetables and whole grains is recommended
- Hepatitis B vaccines prevent the hepatitis B virus, which can cause liver cancer.
- Breast self-examination, mammograms, testicular self-examination, and Pap smears are common screening methods for various cancers.