Blog | Thursday, August 16, 2012

Sunday cancer thoughts

I recently spoke to a woman whose mom has breast cancer. She seemed worried, but not because of the cancer, but because her mom is looking into "alternative" cancer therapies. The standard treatment for her mom is surgery, chemotherapy, and then five years of tamoxifen (I can't recall whether she also gets radiation) and she is not thrilled about it.

The idea behind the treatment is this: surgery removes the bulk of the tumor. Deep in the tumor, the cancer cells are resting, and in the resting state aren't susceptible to chemotherapy. With small tumors, surgery can be curative, but some others require more extensive treatment. Sometimes surgery may leave behind a few tumor cells, or some may have already escaped the breast. Chemotherapy kills these remaining cells, many of which aren't resting but actively trying to make more tumors.

Like hypertension and diabetes, we have decades of data on what works and what doesn't in the treatment of breast cancer. We use this data to drive how we treat patients. Statistics give us guidance, but not a crystal ball. We may know that (and the numbers are made up here) of 100 patients with disease x, 50 had a recurrence without chemo, but only 12 recurred after chemotherapy. But this doesn't tell us whether you will be one of the 12; we just know that your chances are better with the chemo.

Some of the complaints I've heard from people who look into alternative therapies are that the therapies are too toxic, creating too much collateral damage of normal cells; that cancer care seems the same for everyone and doesn't account for the individual; that their regular doctor doesn't seem to care but simply dumps them into the chemo factory.

These are all legitimate concerns, but to get your best chances, you have to overcome your fears about them. We are quite aware that chemotherapy is toxic. Cancer cells are very similar to normal cells and chemotherapy drugs usually simply kill "cells". Cells that are dividing faster (i.e. not resting) are the ones that get killed. This includes most cancer cells, cells in the lining of the gut, hair follicles, and others. Since many more of our cells are resting, most escape unharmed. The lively cancer cells die in higher numbers. Some chemotherapy is more toxic than others, but we follow the data where it leads us and present patients with options.

Sometimes we have better options than others. Most cancers have multiple genetic problems making it difficult to find one critical to the life of the cancer cell but not to normal cells. One type of leukemia, CML, has a perfect target. One gene defect and the protein it produces is responsible for most of the problems that turn normal white cells into CML cells. About 15 years ago, someone discovered a molecule that affects this protein and leaves most others alone. This is one of the best examples of targeted chemotherapy.

Finding medicines that can kill abnormal cells and leave healthy ones intact isn't easy. Anyone who claims to be able to do it but doesn't have the data to back it up is probably selling you something.

I understand the desire of patients to feel like they are being treated uniquely; hopefully they are. But it's usually the patient who is unique, not their disease. The art of medicine comes in treating the patient like a human being while trying to kill the cancer based on how the cancer usually behaves. To tell someone you can treat their cancer with targeted therapies when none are known to exist is an immoral lie. To tell them that you will treat them with compassion and understanding, and treat their cancer with the best proven treatments is good medicine.

Peter A. Lipson, ACP Member, is a practicing internist and teaching physician in Southeast Michigan. After graduating from Rush Medical College in Chicago, he completed his internal medicine residency at Northwestern Memorial Hospital. This post first appeared at his blog, White Coat Underground. The blog, which has been around in various forms since 2007, offers "musings on the intersection of science, medicine, and culture." His writing focuses on the difference between science-based medicine and "everything else," but also speaks to the day-to-day practice of medicine, fatherhood, and whatever else migrates from his head to his keyboard.