Introduction
Cancer is a preventable disease. Cancer cure is a reality if detected early. To offer a better choice of treatment to the patients, it is important that patients are screened, educated to identify the signs of cancer and are assisted to seek medical attention at the earliest.
Oncology is derived from the greek words onkos (Mass, tumour) and logos (study) which best describes the study of malignant disease. Tumours may be either benign or malignant. The term “Cancer” usually is referred to a tumour when there is an uncontrolled growth and spread of cells which may affect almost any tissue of the body. Cancer is not just one disease but is a group of more than 100 different and distinctive diseases which is not contagious.
Incidence of Cancer:
In the world, lung, colorectal and stomach cancer are among the five most common cancers in the world for both men and women. While lung and stomach cancer are the most common cancers worldwide in men, breast and cervical cancer are in women. Among the non communicable diseases, the burden of cancer is increasing. The estimated number of new cases each year is expected to rise from 10 million in 2000 to 15 million by 2020. Some 60% of all these new cases will occur in the less developed parts of the world. Cancer is currently the cause of 12% of all deaths worldwide. In approximately 20 years time, the number of cancer deaths annually will increase from about 6 million to 10 million. The principal factors contributing to this projected increase are the increasing proportion of elderly people in the world (in whom cancer occurs more frequently than in the young), an overall decrease in deaths from communicable diseases, the decline in some countries in mortality from cardiovascular diseases, and the rising incidence of certain forms of cancer, notably lung cancer resulting from tobacco use. Approximately 20 million people are alive with cancer at present; by 2020 there will probably be more than 30 million.
Despite cancer rates in India being lower than those seen in Western countries, it is important to recognize that the incidence is on a rise. Increasing migration of rural population to the cities, increase in life expectancy and changes in lifestyles may be the cause. In India, rates for oral and oesophageal cancers are some of the highest in the world. In contrast, the rates for colorectal, prostate, and lung cancers are one of the lowest. There is a significant variation with age, sex and geography in the incidence of the various types. Risk factors of cancer is also associated with social and economic status. Cancer risk like cervical cancer are highest in groups with the least education. In addition, patients in the lower social classes have consistently poorer survival rates than those in the higher social classes. Lifestyle changes in dietary patterns and tobacco use; occupational exposure to carcinogens and biological factors such as viral hepatitis B infection and human papilloma virus infection also may lead to cancer development.
What causes Cancer?
Cancer begins as a mutation in the DNA of a cell as a consequence of exposure of individuals to carcinogenic agents. This mutation results in failure of mechanisms that regulate normal cell growth, proliferation and cell death. The outcome of this is a tumour. Ultimately, the progress of the resulting tumour from mild to severe abnormality, with invasion of neighbouring tissues or distant dissemination which is also known as Metastases results in “Cancer”.
How is Cancer managed?
The first and most important step in cancer management is diagnosing the condition. Suspicion of cancer is based in the clinical assessment which then leads to performance of appropriate further tests. A firm diagnosis is always made after a histopathological examination of the abnormal tissue. The other sequence of tests include routine and specialized diagnostic investigations like endoscopies, cytology, hormonal tests, biomarker studies and imaging (X-ray to PET CT).
Importance of Screening:
Screening of normal people is done to detect cancer in its early stage and to reduce mortality. Various screening tests are available which are simple and easy. Mammography, cervical smears, endoscopies, examination of faeces for occult blood, serum prostate specific antigen and sigmoidoscopies are some of the routinely done tests.
Immunohistochemistry, Biochemistry and tumour markers:
Immunohistochemistry is part of pathological investigations using antibodies, various intracellular and cellular surface proteins to determine tissue origin of a very undifferentiated tumour, identifying subtypes of common cancers and establishing the presence of oestrogen receptors in breast cancer.
Some of the tumours secrete proteins into blood circulations, which are detected by routine tests of biochemistry. Few of which are unique to a tumour (Eg. CEA, CA 125, Alfafetoproteins), LDH, HCG). Using tumour markers, one can assess the response to treatment and check for recurrence.
Cancer Treatment:
The goals of cancer treatment are early detection, cure and improvement of the quality of life. Care of cancer patients typically starts with recognition of an abnormality, followed by consultation at a health care facility with appropriate services for diagnosis Once diagnosis is made, it is important to ascertain cancer staging, which support identifying the choice of therapy, prognostication, and to standardize the design of research treatment protocols. Optimal treatment of people diagnosed with certain types of cancer detected early, for example, cancers of the uterine cervix and corpus, breast, testis, and melanoma, will result in 5-year survival rates of 75% or more. By contrast, survival rates in patients with cancer of the pancreas, liver, stomach, and lung are generally less than 15%. Some treatments require sophisticated technology that is available only in locations with substantial resources.
Treatment may involve surgery, radiation therapy, chemotherapy, hormonal therapy, or some combination of these. Although surgery is the oldest form of treatment, recently non-surgical role is gaining importance.
Surgery for Cancer:
The role of surgery is to remove localized tumour completely or reduce the size of large tumour to increase the effectiveness of follow-up treatment by radiation or chemotherapy. Surgery has a dual role, it can be done as a diagnostic (staging) procedure as well as a curative treatment, and these two may take place simultaneously.
In addition to curative surgery, surgery may also be performed as a preventive measure (to remove precancerous conditions) and/or a palliative measure (to reduce pain and other symptoms). If curative surgical procedures cause any disfigurement or deformity, reconstructive surgery may be done to repair the damage.
Chemotherapy for Cancer:
Unlike olden days where chemotherapy meant taking any medicine, it is now narrowed to medications to treat cancer. Most chemotherapy drugs are given in the form of tablets, daycare medications as in a vaccine or sometimes given through the blood vessels through intravenous injections in the hospital.
Chemotherapy maybe given as once a day, once a week, or even once a month, based on the type of cancer and the chemotherapy regimen that is ideal for the condition. It is given as long as the regular follow up investigations confirm best treatment results.
Chemotherapy uses cytotoxic treatments which is based on the propensity of cells to die when their DNA is damaged by therapeutic means; hormonal approaches where reducing the circulating hormones reduces the proliferation of some tissues; and other immunological therapies which alters the natural history of malignancy by using a profound stimulus to the immune system like the Monoclonal antibodies.
Radiotherapy for Cancer:
The use of high-energy rays to damage cancer cells and stop them from growing and dividing is the principle used in radiotherapy. It is a local treatment which affects cancer cells only in the treated area by a machine externally or from an implant placed directly into or near the tumor. Some patients receive both kinds of radiation therapy.
Radiation therapy has been in use for the treatment of cancer and other diseases for approximately 100 years. From the time radiotherapy moved into clinical routine, it has undergone several changes to produce numerous developments like generation of higher energy radiation beams for more effective cancer treatment to the development of versatile linear accelerator and patient table designs to enable radiation to be delivered to the cancer from a variety of angles and directions. The implementation of "multi-leaf" collimators (lead shutters) and other beam shaping devices for precision control and shaping of the radiation beam and the use of Computerised tomography (CT), Postron Emission Tomography (PET), Magnetic resonance imaging (MR) and other image data sets to create three-dimensional planning models to accurately guide treatment. With the use of advanced technology the implementation of networked computers to track radiation treatment sessions and patient dose calculations (both planned and accumulated). The final aim of all the above changes, developments and improvements is the effecti
Palliative care
Palliative care ve destruction of cancer tissue while delivering a minimal dose of radiation to adjacent healthy tissues. This has also made treatment easier and shorter for the patient to sustain and the physicians and other healthcare professionals to perform.
is an approach that improves the quality of life of patients and their families facing the problems associated with life-threatening illness, through the prevention and relief of suffering by means of early identification and impeccable assessment and treatment of pain and other problems like physical, psychosocial and spiritual. Improved quality of life is of paramount importance to patients with cancer.
