The early diagnosis of cancer is an expedient that can decrease the mortality and alleviate the morbidity of a cancer. A cancer diagnosed early enough enables a surgeon to extirpate entirely or a radiotherapist to destroy with megavoltage radiation and effect a ‘cure’ (as opposed to ‘palliation’).
The concept of early diagnosis of cancer began in the 1940s, when Papanicolaou (from where the ‘Pap’ smear derives its name) and Traut found that exfoliated cells (exfoliation is a process whereby skin cells, hair, and other ‘surface cells’ constantly age and fall off and are replaced by new cells) can be observed for abnormalities. The abnormalities start from some time (2 years to 10 years) before the lesion actually and becomes “malignant.” At this early stage, the lesion can be called ‘pre-malignant’ and can be easily removed or cauterized (i.e burnt) without even removing the organ where it arose. This is commonly applicable to the cervix (the mouth of the womb) in women.
Subsequently, such early diagnosis was extended to other organs ‘with a surface’ like the oral cavity, pharynx, larynx and lungs (through bronchoscopy), and later, to lumps under the surface, by Fine Needle Aspiration Cytology (FNAC) wherein, a needle (like the ones used for intra-muscular injections) is inserted into the ‘below the surface’ lump and cells drawn from it and studied.
Certain cancers have known pre-disposing factors – like smoking and lung cancer, promiscuity (papilloma virus infection) and cervical cancer, Hepatitis-B infection and liver cancer, ‘khangri’ cancer from use of coal-based hot bags used against the skin in extremely cold places (remote Kashmir). But many other cancers, like breast cancer and ovarian cancers have a hereditary pattern. Hence in those families, it is more relevant to ‘screen’ for early lesions.
The concept of ‘screening’ has evolved since the last 50 years. By definition, it is a test done on an ‘asymptomatic’ individual with the intention of detecting an abnormality before the person is aware of it. So, the test has to be economical enough so that the whole population can be tested. Yet, it has to be accurate. Because, in case of a false positive, the involved person will be turned into a nervous wreck, and in case of a false negative, the doctors would be missing a potential cancer.
Recent advances in imaging technology have made it possible to detect unduly large amounts of glucose being used by parts of the body, which would raise suspicions of an early malignancy (cancer cells use up glucose at a higher rate than normal cells – for their activity and proliferation). So a PET (Positron Emission Tomography which is a higher version of a CT scan) with radio-labelled glucose would detect early malignancy, but is too costly to offer as a screening test.
Ultimately, it is not super technology or recent advances that can help; rather it an integrated approach along with application of the doctor concerned that helps one detect cancers early.
