Cancer is not just one disease but encompasses many different types involving all the organs and tissues in the body. Each type has its own characteristics and its own sensitivities to chemotherapy. We are gradually unlocking the genetic and metabolic codes that are responsible for the growth of each cancer and with that are finding very specific treatments that combat these mechanisms.

Whereas the conventional chemotherapy drugs, which can be very effective, work against more rapidly growing cells, the newer biological agents target proteins in the cancer cell that are over-expressed and therefore act more specifically against the cancer cells.

One of the first of these drugs to be developed, Rituximab, works specifically against lymphocytes that have a certain protein on their surface and has revolutionized the treatment of lymphomas.

Gleevec was developed to act against a very specific protein that caused chronic myelogenous leukemia and has converted a uniformly lethal disease into one where the majority of people live for many years in remission. Herceptin is a drug which acts against a protein over-expressed in about 25 percent of breast cancers and has led to the cure of many women who otherwise would have succumbed to their disease.

At the major oncology meeting in Chicago this month, a new drug was presented that does have activity against melanoma, a particularly aggressive type of skin cancer, where we have few weapons to combat the progression of this disease.

Many other drugs such as these have been introduced into practice leading to a much better ability to control or cure many types of cancer. As more is known about the metabolic pathways in cancer cells, we are realizing that this is considerably more complex than we first thought, and it may be that we have to attack these cells at many different points in the chain to cause them to die.

The excitement over these new types of drug must be tempered by the fact that they are exorbitantly expensive! The cost for a course of one drug can reach more than $100,000, which does not include the cost of the conventional chemotherapy. In our present climate where already we, as a society, cannot afford the cost of health care, how are we going to afford to pay for all of these new weapons against cancer? Obviously this is a dilemma that both our generation and future generations will have to come to terms with.

John Laurie is a medical doctor at the Albert Lea Medical Center, which is part of the Mayo Health System.