Читать книгу Cancer is a Word, Not a Sentence - Miriam Stoppard - Страница 21

Whereas chemotherapy agents are basically drugs that damage all growing cells (to a greater or lesser extent), biologic agents are drugs (usually complex manufactured proteins) that seek and bind to specific targets on the surface of cancer cells. They are—to use a crude analogy—like ‘smart bombs’ that ‘home in’ on specific characteristics of the cancer cells and, hopefully, avoid doing damage to normal cells, which do not have those targets on their surface. When they work well, biologic agents produce much less ‘collateral damage’.

The earliest drugs that worked by biological means, specifically targeting cancer cells by altering one aspect of the internal environment, were hormone treatments, which are still today a major part of the treatment of some cancers, notably cancer of the prostate and cancer of the breast.

Later I’ll show you how biological and hormone treatments are both evolving. Here, the most important thing to realise is that not all cancers can be treated by hormone or biological treatments. There are hormone agents or biologic agents presently available for a lot of cancers, but not for all. For example, if you have breast cancer and it happens to have oestrogen receptors on it, then hormone treatments (such as tamoxifen or letrozole) can be used. If it doesn’t have oestrogen receptors, then those treatments will not be effective. If the cancer cells happen to have a marker called her2/neu on them (see page 57) then a drug called trastuzumab (Herceptin) can be used in addition to chemotherapy. But if the cancer cells do not have that marker on them, Herceptin will not be of any value.

These are just a couple of examples. Biological therapy is evolving very rapidly indeed, and new biologic agents are becoming available for use in different tumours all the time. So you and your medical team will need to discuss those new agents as they emerge.