There is overwhelming knowledge about, how cancer is caused, but all that information does not result in effective prevention and cure. It is clear that cancer is a cellular disease, where homeostatic control of cell division and differentiation is corrupted, resulting in a tumour.

The main characteristics of the tumour is:-

*Lack of cell division control

These cells do not exit cell cycle and continue to possess the potential to divide. They lose homeostatic control.

* Lack of differentiation. These cells cannot differentiate, partially or completely

* They acquire the ability to metastasize, by losing cell-cell and cell substrate interactions.

* They acquire drug resistance.

These changes are the result of mutations and clonal evolution affecting cell – cell and cell substrate interactions which are essential for the homeostatic control of several events like cell cycle progression and exit to differentiation and death.

The main cause of cancer is mutations in key genes mentioned earlier. Intrinsic defects in genetic material lead to susceptibility to mutations. This tendency is aided and abetted by carcinogens. Once a tumour is formed, it expands and gives rise to a tumour mass, which may spread. The spread depends on several factors such as immunity and decrease in natural resistance.

Detection and diagnosis

Since most cancers take a long time to develop, during which there are no symptoms, detection when it happens is at a stage where the disease is well established. Very rarely cancer gets detected early and even then it is ignored by the patient, for several reasons mainly denial. In countries like India, it may be misdiagnosed. Therefore, when patients start treatment it is often very late. Improvements in early detection of cancer has taken place and lot of research is going on to still improve early detection of cancer.

Treatment of Cancer

Once detected the treatment follows the following course :-.

1. Surgery

2. Radiation

3. Chemotherapy.

Surgery

This procedure is for solid tumours which are localised in the body and not spread in different areas. It is also not applicable for cancers of the blood, which are spread all over the body. Surgery removes the tumour leaving healthy tissues. Surgery is the successful method of treating cancer. Once all the cancer is remove, the chances of recurrence is very less. However, it is difficult to remove the last remnants, especially in the margins, because they are undetectable. This results in local recurrence within six months. To prevent this radiation is given to the margins after the removal of the tumour. This radiation results in breakdown of the substrate and allows spread of tumour.

Radical surgery which was practiced earlier did not result in better results and was abandoned

Radiation

This procedure involves use of use of ionising radiation which is cyto- toxic and very effective in killing cancer cells. Though very effective in killing cancer cells, they suffer from a lot of collateral damage to normal tissues surrounding the tumour. The collateral damage may be so severe that it limits the use of radiation therapy. The radiation therapy equipment has been improved a lot but still result in severe side effects.

Another danger is that radiation can result in secondary tumours . Radiation is not effective in disseminated cancers such as blood cancers. Some others such as renal cancers and mylomas are also resistant. It is mostly used in head and neck cancers and localised breast cancers after the surgical removal of the main tumour mass, to prevent local recurrence especially in the margins. It is also used on draining the lymph nodes to prevent spread.

Chemotherapy

It involves the use of cytotoxic chemicals to kill the tumour cells. The pioneer of this form of cancer therapy was Dr. Emanneualle Farber of the Boston Children Hospital, U.S.A. Chemotherapeutic drugs are directed to the different aspects of the cell cycle . Since the proportion of cancer cells progressing through various stages of the cell cycle is higher than normal cells in the patient’s body, these cancer drugs manage to kill them effectively. When it was used by Dr.Farber, it gave dramatic results and all the treated patients going into remission. However the disease relapsed. In spite of these reverses, chemotherapy remains the mainstay in cancers which present themselves in a dis- seminated form.

The main problem with chemotherapy is that the cytotoxic drugs do not discriminate between cancer and normal cells and higher doses kills both of them. The cancer cells due to the plasticity are able to activate genes, which makes them drug resistant, whereas normal cells do not have this capacity. When this happens chemotherapy becomes harmful.

The above discussion proves that the therapies most commonly used are irrational to treat cancers, because they are not specific to the cancer cell, but is generally cyto- toxic. This problem is also seen in radiotherapy. Surgery suffers from the fact that tumours escape removal because they are spread to rest of the body.

Research to make these therapies cancer specific while sparing the normal tissue is going on but the results are not encouraging. Various monoclonal anti body based therapies are touted as being tumour specific, but except making the cost of treatment unbearably high, they do not achieve better cure. The most glaring aspect of these research based therapies is that, it is unaffordable, while achieving marginal improvement in cure rates .

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