Tamoxifen may be magic pill against breast cancer
Tamoxifen may be magic pill against breast cancer
STAR trials to compare tamoxifen, raloxifene
The cancer treatment community is buzzing with barely suppressed excitement over the FDA’s approval of tamoxifen as a preventive measure for women at high risk for developing breast cancer.
Experts say the drug, approved in October by the FDA for prophylactic purposes, is likely to change the face of cancer management the same way cholesterol-lowering drugs and ACE inhibitors changed heart disease management.
"There is huge support for the concept," says Harmon Eyre, MD, chief medical officer of the American Cancer Society (ACS) in Atlanta. "This is the first broadly indicated chemo- preventive agent that has been proven in very wide-scale trials.
"In reality, breast cancer is the No. 1 health care concern for women in America, and the drug tamoxifen has been demonstrated to have a substantial risk reduction over a period of approximately five years for the women who took the drug."
Tamoxifen and complex advice
Trials showed tamoxifen citrate, marketed by Zeneca Pharmaceuticals in Wilmington, DE, under the brand name Nolvadex, reduced the incidence of invasive breast cancer by substantial numbers (see box, right).
Reductions in the incidence of breast cancer were seen as early as the first year of the trial, which began in 1992 and is continuing through the six-year follow-up.
Researchers used the Gail model to determine high risk for breast cancer. Risk factors included in the model are:
• age (risk of breast cancer increases with age);
• number of first-degree relatives with breast cancer (mother, sister, or daughter);
• previous breast biopsies with or without atypical hyperplasia;
• age at first live birth;
• age at first menstrual period;
• women with a history of lobular carcinoma in situ (LCIS).
Eyre says there is a great deal of confusion among physicians and patients about the use of tamoxifen in balancing risk and benefits.
The National Cancer Institute has produced a "risk disk," a computer program in which a woman can enter her risk factors to determine whether tamoxifen is appropriate for her.
"In my mind, that message is if you have to go to a computer program to determine the applicability of this, that is something that is so far beyond the sophistication level of this country [of] our primary care doctors that it will never happen," Eyre says.
Instead, he makes a personal recommendation since the ACS has not yet issued a formal statement on the issue.
"The message can be incredibly more simple than that," he says.
"All women over age 60 in America in who are concerned about breast cancer should discuss with their health care providers whether or not it is reasonable for them to take the drug tamoxifen for five years," says Eyre. That allows the doctors to discuss with them the potential risk of endometrial cancer or probable phlebitis and pulmonary emboli. Then, make a decision whether or not they should take that drug."
Of the 26 million women in the United States over 60 who are concerned, "there is every reason to feel it is appropriate for them to take the drug, and that’s the huge majority," Eyre concludes.
For women between the ages of 35 and 59, personal risk factors must be very carefully assessed, Eyre says. "That’s based on a prior history of breast cancer, a biopsy showing proliferative breast disease or a very strong family history and some menstrual- and pregnancy-related risk factors.
Identify potential candidates
"The ACS believes women should be encouraged to take advantage of this opportunity," Eyre says, "and doctors should be able to identify the women for whom such treatment would be appropriate. If they don’t want to learn how to monitor or prescribe it, they need to direct women toward an oncologist in their community who would."
The ACS is currently producing educational materials for health care professionals and the public on the issue.
Arthur Michel, MD, medical director of the Highland Park Hospital Breast Center in Highland Park, IL, and a principal investigator for STAR (Study of Tamoxifen and Raloxifene comparing the two drugs that begins this month), says women interested in the drug should participate in STAR.
Raloxifene, another drug considered for prophylactic use for breast cancer and under development by Eli Lilly and Co. of Indianapolis, may have fewer side effects, including less risk of endometrial cancer, researchers theorize.
"If someone at high risk for breast cancer is not eligible for the study, I would have no argument in using tamoxifen as a preventative," Michel says.
"STAR is going to answer some very, very important questions," Michel says. "I would highly recommend that at-risk women participate in the trial."
The thorny issue of cost that will be eliminated for the 22,000 women who participate in STAR, since the drugs will be free.
Managed care has not yet weighed in on the issue of spending an estimated $5,000 for the five-year recommended course of tamoxifen.
Managed care is going to take some convincing of the long-term value of such an expenditure says Ivor Benjamin, MD, assistant professor in gynecologic oncology and associate director for clinical information systems at the University of Pennsylvania Health System in Philadelphia.
"They’re going to have to be convinced it’s effective, since the almighty dollar is all powerful," says Benjamin, while saying the prophylactic benefits of tamoxifen are an "important discovery" that need to be clinically re-confirmed.
The numbers don’t lie, so managed care providers need to sit up and pay attention, counters Eyre of the ACS.
"Managed care shouldn’t be concerned about the cost. They will be in big jeopardy if the drug is denied, since the No. 1 issue in malpractice cases in America is the failure to diagnose breast cancer."
He concludes, "The risk of malpractice changed attitudes toward mammograms, and it will likely change attitudes toward tamoxifen as well."
Harmon Eyre, MD, medical officer of the American Cancer Society, can be reached at (404) 329-7740.
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