What happens if some breast cancer cells remain after chemotherapy?

If some breast cancer cells remain after chemotherapy, a different treatment may be used. Often different drugs are used to combat a problem in women with breast cancer called “clonality.” Say a person has a relatively small breast cancer, but it has spread to a lymph node under the arm. Presumably it may be somewhere else as well and because of this, chemotherapy is recommended. The treatment kills 98% of the cells. The remaining 2% however, are resistant.

This is similar to the well-known phenomenon of antibiotic resistance seen when treating some bacterial infections. The 2% of cancer cells that survived the chemo become the next epicenter of cancer (a “recurrence”). Fortunately some of these will be sensitive to another form of chemo. Some may be surgically removed (in selective cases) and some will be sensitive to radiation. If the “clonality” problem arises again (98% of the 2% cell population), these cells may be susceptible to yet another agent. The genetic basis of cancer will continue to guide treatment decisions and increasingly individualize the choice of therapies used, many of which have fewer side effects.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.