Readers of this blog know that I have a keen interest in precancers. Precancers are the lesions that precede the development of cancers. Unlike cancers, precancers are easy to treat. If we successfully treated precancers, we would stop cancers from developing.
Why are cancers so easy to treat? There are several reasons. First, precancers are fragile lesions. Spontaneous regression is common in precancers. It is easier to treat a localized lesion that is always skirting-on-the-edge of its existence, than to treat fully developed cancers, that virtually never regress spontaneously and that have metastasized to throughout the body.
In addition, fully developed cancers are biologically complex, with many different genetic and epigenetic alterations that confer their malignant phenotype (properties). When a cell has many different genetic lesions, you would expect it to be difficult (or impossible) to effectively treat cancers by targeting any single molecular alteration. This has proven to be the case. Most of the new chemotherapeutic drugs, that target specific molecules, have not proven effective at curing the common cancers (i.e., epithelial cancers of lung, colon, prostate, pancreas). However, there has been remarkable success using the newer, targeted agents, against cancers that have simple genetic alterations (such as chronic myelogenous leukemia, GIST, and a variety of rare cancers).
Because the molecular targeted therapies work best against cancers with simple genetic alterations, you can expect them to work better against the precancers than against the cancers. This is because during carcinogenesis (cancer development), genetic alterations are continuously increasing in number. Precancers will never have as many genetic alterations as the cancers into which they eventually develop. Therefore, precancers, like the tumors that respond best to molecularly targeted agents, are genetically simpler than the common epithelial cancers that account for the majority of cancer deaths.
In the next few blogs, I will discuss some of the issues related to the precancers that were not discussed in my recently published book on the subject.
- © 2010 Jules Berman
