Paclitaxel from Yew for Breast Cancer

A new study suggests that paclitaxel, originally derived from the Pacific yew tree, may improve survival in women with breast cancer.

Taxanes are compounds produced by plants in the genus Taxus, such as the Pacific yew tree. Researchers from Eastern Cooperative Oncology Group in Philadelphia, PA, compared the efficacy of two different taxanes, docetaxel and paclitaxel, given either weekly or every three weeks, in the adjuvant treatment of breast cancer.

Paclitaxel is isolated from the bark of the Pacific yew tree (Taxus brevifolia) and is available under the brand name Taxol®. As early as 1971, paclitaxel was used as an anti-tumor drug in clinical trials run by the U.S. National Cancer Institute. Taxol® has succeeded in treating advanced ovarian and breast cancers in clinical trials.

Paclitaxel is now approved by the U.S. Food and Drug Administration (FDA) and is hailed as one of the most significant advances in cancer chemotherapy in recent history.

In the study, 4,950 women with axillary lymph node-positive or high-risk lymph node-negative breast cancer first received four cycles of intravenous doxorubicin and cyclophosphamide at three-week intervals and were then assigned to paclitaxel or docetaxel, given intravenously at either three-week intervals for four cycles, or at one-week intervals for 12 cycles. The primary end point was disease-free survival.

Compared to patients receiving the standard therapy of paclitaxel every three weeks, the odds ratio for disease-free survival was 1.27 among those receiving weekly paclitaxel, 1.23 among those receiving docetaxel every three weeks and 1.09 among those receiving weekly docetaxel.

As compared with standard therapy, the study found that weekly paclitaxel was associated with improved survival. In a subgroup of patients whose tumors expressed no human epidermal growth factor receptor type 2 protein, an exploratory analysis found similar improvements in disease-free and overall survival with weekly paclitaxel treatment regardless of hormone-receptor expression. Grade 2, 3 or 4 neuropathy (nerve pain) was more frequent with weekly paclitaxel than with paclitaxel every three weeks (27 percent vs. 20 percent).

The study authors concluded that weekly paclitaxel after standard adjuvant chemotherapy may improve disease-free and overall survival in women with breast cancer.

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For more information on yew, please visit Natural Standard's Foods, Herbs & Supplements database. For more information on breast cancer, please visit Natural Standard's Medical Conditions database.

Comments

[Joyce]

My first thought is how wonderful…another benefit from nature. Then I think of all the deliberate destruction of trees by large businesses and how we may be chopping down cures and treatments for diseases like breast cancer.

[Leah Cohen]

What about the adverse effects of other standard of care treatments for breast cancer? I would assume that there would also be an extensive list of negative effects, both short term and long term.

[Sandra]

The disturbing new analysis comes from the Cancer and Leukemia Group B (CALGB), a research and clinical trials consortium that includes Larry Norton, MD, Eric Winer, MD and other eminent doctors at Memorial Sloan-Kettering Cancer Center and elsewhere. The study used modern genetic tools to reanalyze data that were gathered in a clinical trial in the 1990s.

In the CALGB study, 3,000 women with locally advanced breast cancer were given the ACT regimen. While Taxol only benefited a minority of patients, its adverse effects were experienced by the majority of patients.

The adverse reactions to Taxol are well known. These are tabulated in the drug's prescribing information and can be readily found at the FDA Web site, www.fda.gov. Here are a few statistics, derived from a study of the single-use of Taxol in 812 breast cancer patients.

Neutropenia - 52 to 90 percent of patients, depending on the dose.
Leukopenia - 17 to 90 percent
Anemia - 16 to 78 percent
Infections - 30 percent
Hypersensitivity reactions - 41 percent
Hypotension - 12 percent
Abnormal ECGs - 23 percent
Peripheral neuropathy, any symptoms - 60 percent
Myalgia/arthralgia - 60 percent
Nausea and vomiting - 52 percent
Alopecia (hair loss) - 87 percent
Injection site reactions - 13 percent

Some of these problems, such as numbness and tingling in the hands and feet, persist for months and years following Taxol treatment.

In women who had tumors that were estrogen-receptor positive, and in women whose tumors did not over-express the HER2 gene - and about 80 percent of all women who get breast cancer fall into this category - Taxol added no benefit at all to their survival odds.
http://www.cancerdecisions.com/102807.html

[Leah Cohen]

There are similar articles that report on the effects paclitaxel, such as "Benefit of taxanes as adjuvant chemotherapy for early breast cancer: pooled analysis of 15,500 patients" (Bria, 2006).

Earlier research from 2007 has reported on the effects of paclitaxel dose density and adjuvant treatment. One study is "Dose-dense therapy in the treatment of early-stage breast cancer: an overview of the data." (McArthur, 2007); however, I do not believe that this included paclitaxel therapy alone.

[Jamie]

When a person is diagnosed with invasive breast cancer, the first line of standard treatment usually consists of surgery and then chemotherapy. Lately, more and more people are undergoing neoadjuvant chemotherapy, which involves giving a patient drugs to shrink the tumor before surgery.

This study aimed to find out whether weekly doses of paclitaxel before surgery or other treatment would benefit patients with invasive, early-stage breast cancer.

[Pamela]

It should be noted that an ideal weekly dose of paclitaxel has not been established. Because paclitaxel is highly toxic at higher doses, its clinical usefulness may be limited to some degree.

[Leah]

Here's a quote from the National Cancer Institute press release:

"According to Jennifer Eng-Wong, M.D., M.P.H., a medical oncologist with the National Cancer Institute’s Center for Cancer Research, 'This study supports a number of [other] studies that examine the dose interval for paclitaxel. It provides mounting evidence that the timing of chemotherapy is important. The shorter dose interval is going to be better for metastatic and adjuvant therapy for breast cancer.'"

[Jer]

“We have shown that changing the schedule of paclitaxel results in significantly improved ability to eradicate invasive cancer in both the breast and lymph nodes,” concluded Green and the other study authors.

This and other studies suggest that it may be beneficial to decrease paclitaxel dose intervals in patients with early-stage breast cancer.

[Polly]

Treating breast cancer with taxanes is not news. They have been using it for years, and it has been heavily studied. In fact, recent studies have shown that Taxol may have little or no additional benefit for estrogen receptor positive, her2neu negative patients.

Also, just because Taxol is derived from a tree does not mean that it is not technically a chemotherapy or that it isn't a highly toxic substance that can take patients to the brink of death. I know. I was on it for three months and had to get shots of Neupogen almost daily to boost my white blood cell counts so that I would not have to be hospitalized due to a critically compromised immune system.