William Aiken

Radiotherapy involves the use of high energy, ionising radiation to treat a variety of diseases. Radiotherapy may be administered with the intention of curing, that is, eradicating a disease, or it may be administered for palliative purposes, that is, to provide relief from painful and/or distressing symptoms which adversely affect quality of life or aggravate the patient's underlying condition. Radiotherapy finds its greatest utility in treating a variety of cancers, including prostate cancer.

Cancer cells are abnormal cells which rapidly turn over or reproduce in an unregulated manner. They are immortal cells which possess the ability to directly invade adjacent tissues and organs and spread in a discontinuous manner (metastases) via the lymphatic and circulatory systems to distant sites where they take root and form new 'growths'.

Damage cancer cells

Radiotherapy works essentially by arresting the reproduction or turnover of cancer cells such that when it comes time for the cancer cells to divide, they cannot and subsequently die. Radiotherapy takes advantage of the fact that cancer cells generally turnover or reproduce much more rapidly than cells from normal tissues, and are therefore much more sensitive to the effects of radiotherapy than normal tissues.

Radiotherapy exerts its effects by directly or indirectly causing free radical damage to the DNA in the nucleus of the cancer cell which renders it incapable of reproducing and thereby marking it for cellular death.

In the last two decades, anumber of refinements in the application of radiotherapy in treating cancer have taken place which have simultaneously improved its efficacy and decreased its rate of complications. One of these developments is conformal radiotherapy which allows the externally applied radiation beam to be more precisely configured to the contours of the organ being treated, thereby permitting an escalation in the applied dose and a simultaneous sparing of normal surrounding tissues.

This dose escalation of a more precisely focused radiation beam means a higher likelihood of cancer cells being killed which translates into higher and longer lasting cure rates. Indeed, where prostate cancer is concerned, radiotherapy now rivals surgery in treating early disease where effecting a permanent cure is concerned. External beam radiotherapy is used to treat organ-confined, that is early prostate cancer and locally advanced prostate cancer. When treating the latter, it is used in combination with hormone therapy. External beam radiotherapy may also be used with great utility in effectively treating painful metastases to bone and other areas.

Implanted seeds

Radioactive seeds may also be directly implanted into the prostate to treat early prostate cancer, a procedure known as brachytherapy which is available in Jamaica at the Radiation Oncology Centre on Ripon Road. Careful patient selection is paramount in the success of this day-case procedure.

Brachytherapy is ideally reserved for patients with prostate specific antigen (PSA) levels below 10ng/ml, low or intermediate grade tumours, and those having a prostate size which is not inordinately large. Patients who are placed in a higher cancer risk category by virtue of having a higher PSA and/or grade are best treated with external beam radiotherapy or radical surgery or combinations of these with or without hormone therapy.

Prostate cancer patients in a low cancer risk category, i.e., PSA less than 10ng/ml, and Gleason scores of six and less, with no abnormality of the prostate felt on digital rectal examination, will usually do well regardless of which method of treatment is selected, be it brachytherapy, external beam radiotherapy or radical surgery as prognosis here is determined primarily by the characteristics of the cancer itself rather than the modality of treatment administered.

Radiotherapy is a viable treatment option for patients with prostate cancer and should be considered when either cure or palliation is the primary treatment objective.