Older Women with Positive Lymph Nodes Benefit from Chemotherapy

Reviewed study: "Older Women with Positive Lymph Nodes Benefit from Chemotherapy" by H. Muss et al., Journal of the American Medical Association, March 2, 2005

Is this for me?: If you're 65 or older with lymph-node positive breast cancer (cancer cells found in lymph nodes) and in good overall health, you might want to read this article.

Background and importance of the study: As we grow older, our risk of developing breast cancer (and most other diseases) goes up. Almost half of all new breast cancers in the United States are in women 65 or older.

Women of all ages with node-positive breast cancer who get chemotherapy have a lower risk of the cancer coming back, and a lower risk of dying from the cancer, than node-positive women who are similar in age but who do not receive chemotherapy.

Even though chemotherapy has a lot of benefits, some doctors think that it's not offered to older women as often as it could be. So, if you have node-positive breast cancer, are 65 or older, and have not been offered chemotherapy, you may want to discuss this treatment option with your doctor.

One of the things you'll want to talk about is the side effects of chemotherapy. Because these side effects can be strong, doctors who are considering chemotherapy for older women with node-positive breast cancer prefer to give it to those women who are in good overall health and do not have other significant illness such as heart disease.

If you consider receiving chemotherapy, you should also know that chemotherapy usually means taking multiple drugs. You and your doctor have choices about which chemotherapy regimen (combination of drugs) to use. One of the most important decisions is whether to use a standard treatment or an aggressive one. Research indicates that, compared with the older, standard chemotherapy, newer, more aggressive chemotherapy may significantly reduce the risk of breast cancer coming back and significantly improve survival. However, that newer chemotherapy will likely be more toxic (harmful to the body) than the older chemotherapy. Furthermore, not much is known about how women 65 and older with node-positive breast cancer will benefit from aggressive chemotherapy and how they will tolerate its side effects.

Finally, for women who have both lymph node–positive and hormone receptor–positive breast cancer, receiving chemotherapy before hormone therapy (such as tamoxifen and aromatase inhibitors) is an additional consideration, as this has been shown to improve treatment outcome.

In the study reviewed here, researchers compared the benefits of standard versus aggressive chemotherapy for women with breast cancer in different age groups. They wanted to find out whether aggressive chemotherapy benefits older women with node-positive breast cancer. The researchers also looked at chemotherapy-related mortality (death). This study did not focus on the many side effects that can occur with chemotherapy.

Study design: This study was retrospective. This means that researchers evaluated information on the benefits of standard versus aggressive chemotherapy for women who had already been treated in the past.

Researchers from a number of cancer centers across the United States looked at the results of four clinical trials conducted between 1975 and 1999 by a national clinical research group called Cancer and Leukemia Group B (CALGB). The researchers analyzed the results for 6487 women with node-positive breast cancer in the trials.

Each trial compared at least two different types of chemotherapy treatments: one type that was considered more aggressive (and possibly had more side effects), and another type (or types) that was considered less aggressive (standard). The chemotherapies were also different in dose and in the number of drugs given.

The four trials compared these treatments:

Trial CALGB 7581 compared:

• CMF (cyclophosphamide, methotrexate, and fluorouracil) (the least aggressive treatment) and
• CMF +MER (CMF plus methanol extraction residue of bacillus Calmette-Guerin) (less aggressive) and
• CMF +VP (CMF plus vincristine and prednisone) (more aggressive).

Trial CALGB 8082 compared:

• CMF + VP (less aggressive) and
• CMF +VP; VATH (CMF +VP, followed by vinblastine, doxorubicin, thiotepa, and Halotestin [chemical name: fluoxymesterone]) (more aggressive).

Trial CALGB 8541 compared:

• a low dose of CAF (cyclophosphamide, doxorubicin, and fluorouracil) (least aggressive) and
• a moderate dose of CAF (less aggressive) and
• a high dose of CAF (more aggressive).

Trial CALGB 9344 compared:

• AC (doxorubicin and cyclophosphamide) (less aggressive) and
• AC + T (AC plus Taxol [chemical name: paclictaxel]) (more aggressive).

The researchers divided the women into three groups according to age:

• 50 years or younger (3506 women),
• 51 to 64 years (2439 women), and
• 65 years or older (542 women).

In all three age groups, similar percentages of women had estrogen receptor–positive breast cancer:

• 53% of women age 50 or younger,
• 57% of women age 51 to 64, and
• 58% of women age 65 or older.

Information on the progesterone receptor status of the women was not available in enough women to be considered useful. Tamoxifen use was similar among the three age groups (40%, 43%, and 37%, respectively) in the two studies (CALGB 8541 and 9344) in which tamoxifen was included.

Half the women were followed for more than nine years and half were followed for less time. The researchers looked at three outcomes in the three groups:

• overall survival (how long the women lived, with or without the cancer coming back),
• disease-free survival (how long the women lived without the cancer coming back), and
• treatment-related mortality (how many women died as a result of treatment).

Results: The researchers found that having more aggressive chemotherapy—as opposed to less aggressive chemotherapy—improved overall survival, regardless of age. The chances of survival went up by an extra:

• 17% for women age 50 or younger,
• 16% for those age 51 to 64, and
• 27% for those age 65 and older.

Overall survival was significantly lower in women age 65 or older, but this was due to causes other than breast cancer.

Regardless of age, women who had more aggressive chemotherapy also had more years of disease-free survival. The chances of disease-free survival went up by an extra:

• 18% for women age 50 or younger,
• 20% for women age 51 to 64, and
• 42% for women age 65 and older.

Overall, 33 women (0.5%) died as a result of treatment toxicity (harm caused by the drugs). Older women were more likely to have this happen. The researchers did not indicate which deaths were due to aggressive chemotherapy and which were due to standard chemotherapy. Chemotherapy-related mortality was:

• 0.2% for women age 50 or younger,
• 0.7% for women age 51 to 64, and
• 1.5% for women age 65 and older.

The researchers also found that only 542 (8%) of the women were aged 65 or older and 152 (2%) were aged 70 or older at the time of treatment. The study also indicated that no tamoxifen use was associated with shorter disease-free survival and overall survival.

Conclusions:

The researchers concluded that women 65 and older with node-positive breast cancer in generally good health got the same benefits from chemotherapy as younger women did. They said that chemotherapy should be considered for use in these older women just as it is for younger women. However, the researchers also said that the older women had a higher rate of chemotherapy-related mortality than the younger women. They noted that other studies have shown that chemotherapy's life-threatening effects are greater among older women than younger ones.

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