Having discussed about what is cancer, its prevention, its warning signs and symptoms, ways to diagnosis, importance of early detection; now I will briefly explain the general treatment concepts of cancer, which entails following:
It is the most common and most important way of treatment which has been practiced for ages even before Christ. It is used for solid organ malignancies and aims to removes diseased area in totality. Cancer is an infiltrative disease and hence a cancer surgeon has to remove more tissue then is obviously diseased so as to get what is called as “negative margin”, and also remove “maximum number” of draining lymph nodes of the concerned area. This is the hallmark of a good cancer surgery. Other than this, surgeon has the onus of preserving anatomy and normal physiology as far as possible and cause least possible disfigurement and damage.
Surgery is offered only if the disease is localized and has not spread to other parts, where in it offers the best chance of cure. However, in very carefully selected cases, surgery can still be done even if the disease has spread, albeit limited.
It is the use of gamma rays, the same we use during X-ray, but at much higher doses, to irreparably damage the cancer cells’ DNA. Most treatments are spread over a few weeks and are given on a continuous daily basis. Each (daily) treatment takes about 3-10 mins depending on the complexity of the plan.
Many times radiotherapy is used as an adjunct to surgery to facilitate clearing of cells which may have been left behind and avoid local recurrences. Sometimes it used as a definitive therapy when surgery is not possible due to extensive local infiltration. Yet at other times it is useful in palliating symptoms of pain and obstructions in late stage cancers.
Advancements in techniques of radiotherapy such as intensity modulation – has enabled delivering very high doses without causing collateral damage to normal tissues and hence improving cure rates and decreasing side effects. Also, now it is possible to target even moving abnormalities such as lung cancer during phases of respiration with high doses by techniques of image guidance. Some newer techniques of precision radiotherapy such as cyber knife are also finding utility but in highly selected cases.
This includes use of cytotoxic drugs that can kill dividing cells. Cytotoxic drugs make use of the concept that rapidly dividing cells be rendered maximum damage when administered systemically. Off course, other dividing cells such as hair, nails, blood cells, intestinal lining etc also get damaged in turn causing side effects, but doses of drugs are generally kept with in tolerable limits. There are many different classes of chemotherapy with different mechanisms of action and different side effect profile. Each cancer type has a preferable chemotherapy regimen and not all class of drugs can be used for all cancers.
The choice of regimen and drugs are laid by very standard guidelines which are based on evidence from science.
Chemotherapy is mostly used as an adjunct to surgery which in turn decreases chances of recurrence both local and distant. Also, it is used in combination with radiotherapy to potentiate cancer kill and sometimes before both so as to decrease local infiltration and make local treatment more amenable.
In later stages, chemotherapy aims at decreasing symptoms of cancer and increasing survival. For blood related cancers such as lymphoma, leukemia and myeloma, chemotherapy remains the mainstay of the treatment.
Newer drugs aim at improving efficacy and decreasing side effects by various techniques such as nanoparticalization, binding with albumin or covering drug molecule with liposomes (lipids) etc.
The new era now brings in targeted therapy for treating cancer which limits collateral damage to minimal and appears to be the future of successful cancer therapy. I will discuss on this in next issue.
Certain cancers are amenable to hormonal manipulation as they are derived from hormone sensitive areas and these are namely breast, prostate and neuroendocrine cancers.
Hormones have a trophic effect on normal breast and prostate tissue and so much for cancers derived from them. Such hormones can be blocked by simple drugs and with minimal side effects. Hormonal therapy is helpful in decreasing recurrences in early stages when used as adjunct to surgery, radiotherapy and chemotherapy. It can also be used as definitive therapy in late stages, and in a properly selected case can be even more effective than chemotherapy.