Chemotherapy in Metastatic Cancer

Patients who develop metastatic disease (ie, who relapse at distant sites) are generally not curable. Drug therapy, however, is often effective at shrinking tumors and improving quality of life.

The most active agents for treatment of metastatic breast cancer are the following:

Anthracyclines such as doxorubicin (Adriamycin) or epirubicin (Ellence). To date, anthracyclines have offered a slight survival advantage over other agents. Patients who carry the HER-2/neu gene and have hormone receptor-negative tumors appear to be particularly responsive to the effects of anthracyclines.

The taxanes paclitaxel (Taxol) and docetaxel (Taxotere). Paclitaxel has been reported the greatest improvements in survival and recurrence reduction. Docetaxel is also showing promise.

Capecitabine (Xeloda) in combination with docetaxel extended survival by three months in one 2000 study compared to paclitaxel alone. (The combination had severe side effects, however, and more comparison studies are needed.)

Other drugs showing some promise in chemotherapeutic regimens for metastatic cancer include vinorelbine, and gemcitabine, gemcitabine, platinum-based agents (cisplatin and carboplatin), edatrexate, and losoxantrone.

Side Effects of Chemotherapy

Side effects occur with all chemotherapeutic drugs; they are more severe with higher doses and increase over the course of treatment. Common side effects include the following:

Nausea and vomiting. Drugs known as serotonin antagonists can relieve these side effects in nearly all

patients given moderate drugs and most patients who take more powerful drugs.

Diarrhea.

Temporary hair loss.

Weight loss.

Fatigue.

Anemia.

Depression.

These side effects are nearly always temporary. Most patients are able to continue with normal activities for all but perhaps one or two days a month.

Serious complications can also occur and may vary depending on the specific agents used. They include the following:

Increased chance for infection (from suppression of the immune system).

Liver and kidney damage.

Bleeding.

Menstrual abnormalities and premature menopause (occurring in about 30% of women, particularly in those over 40).

Rarely, secondary cancers such as leukemia.

Between a quarter and a third of women report problems in concentration, motor function, and memory, which may be long-term.

Cumulative doses of anthracyclines can damage heart muscles over time and increase the risk for heart failure. (A newer, encapsulated form of the anthracycline, doxorubicin called Doxil, appears to pose a much lower risk for heart disease, but has not been approved for breast cancer use as of the date of this report.)

Taxanes can cause a drop in white blood cells and possible problems in the heart and central nervous system.

Allergic reactions can occur, more often in Taxol than Taxotere; taking a steroid before taxane administration can help prevent such reactions. Taxane therapy may also cause severe joint and muscle pain in some patients, relievable with corticosteroids.

Last updated Jan 4/07