New drugs for cancer therapy

By Joanna Lin

This interactive health column is jointly run by The Jakarta Post and Singapore-based Parkway Group Healthcare. The column covers various medical topics and appears twice a month. Readers are encouraged to ask questions through The Jakarta Post's jktpost2@cbn.net.id or Parkway's san-san@gleneagles.com.sg

SINGAPORE (JP): A cancer develops when normal healthy cells lose the ability to control their normal growth and keep multiplying due to changes occurring in the genetic makeup.

Abnormal cells join together to form a growth of tumor, and this invades and destroys the surrounding tissues.

The incidence of cancer in Asian countries is increasing sharply.

Cancer treatment consists mainly of curative surgery in early stage disease to remove the tumor. However, this is often not sufficient, due to the migration of cancer cells to other parts of the body.

This is called metastases and, when this occurs, can lead to the death of the patient. Surgery is therefore often followed by chemotherapy with or without radiotherapy to reduce this risk. In studies in Asia, America and Europe, this has been found to improve overall survival.

Individuals who have advanced cancers, chemotherapy and radiotherapy are often the only means of controlling the disease and improving symptoms for the patient and may even prolong life.

A lot of fear and uncertainty arises when people hear the word chemotherapy, primarily because old drugs used to cause substantial side effects which sometimes made patients feel worse than with the original disease.

Often, these drugs were not very effective. Over the last few years, however, there have been many exciting developments in cancer therapy.

New drugs used in cancer therapy have less side effects, and are often more effective. There are now more indications for the use of chemotherapy, and many patients with different cancers are benefiting from these new drugs -- breast, lung, colorectal, liver, pancreas, stomach to name a few. These new drugs can now relieve symptoms and prolong life without sacrificing the quality of life of the patient.

An example of these new drugs are the taxanes. These drugs can be used for a wide variety of cancers, including ovarian and breast cancers. It can be used also for patients who suffer from lung, head, neck, stomach, esophagus, prostate and bladder cancers.

Irinotecan and Oxaliplatin are two new drugs which have been found to be effective for colorectal cancers, which are tumors traditionally relatively resistant to chemotherapy.

Gemcitabine is another new drug which has been found to be active in liver cancer and pancreatic cancer, as well as breast and lung cancer.

There are now also many new drugs that can help with the side effects of cancer treatment. These include the 5HT3 antagonists which have revolutionized the treatment of nausea and vomiting post chemotherapy and radiotherapy, growth factors can be used to reduce the side effect of low white counts, and amifostine can reduce nephrotoxicity and low blood counts.

New drugs that will be available in a few years' time include those which can prevent blood vessels which supply the tumor from growing -- called antiangiogenesis drugs.

On the horizon, there will also be gene therapy which aims to replace the defective gene in cancer cells. In summary, the new millennium holds much promise in cancer therapy.

-- The writer is a consultant at Medical Oncologist, Gleneagles Medical Center.