According to the latest American Society of Clinical Oncology (ASCO 2014) guidelines, all patients with hormone-positive breast cancer should choose hormonal adjuvant therapy and maintain it for up to 10 years.
For premenopausal and perimenopausal women with breast cancer who have completed 5 years of adjuvant tamoxifen therapy, they should continue to receive the drug for the next 5 years. And for postmenopausal patients, after 5 years of tamoxifen treatment, they should also continue tamoxifen or switch to an aromatase inhibitor (AI) for another 5 years. Harold J. Burstein, PhD, of the Dana-Farber Cancer Institute in Boston, and colleagues wrote.
The recommendations were based on the latest follow-up data, which showed some prolongation of survival and a significantly lower risk of recurrence of bilateral breast tumors with long-term use of tamoxifen. The report was published in the latest online edition of JCO.
”The current guideline update synthesizes the results of a large number of recent multicenter randomized clinical studies that have well addressed the issue of duration of endocrine therapy,” said the study authors, adding that “the aforementioned studies include two large randomized cohort studies, both published at the 2013 ASCO meeting, and both addressed the issue of itamoxifen duration. Guidelines updated back in 2010 primarily referenced the historical standard of 5 years of tamoxifen monotherapy maintenance treatment, as earlier studies showed no clinical benefit from extended tamoxifen treatment.”
For patients with hormone receptor-positive early-stage breast cancer, the updated 2014 ASCO committee recommendations, based on recent research findings, are as follows.
In patients with newly diagnosed breast cancer: for premenopausal and perimenopausal women, tamoxifen should be used as the starting adjuvant therapy should continue for 5 years, with subsequent treatment determined by the patient’s menstrual status over the next 5 years.
For patients with unknown menstrual status, tamoxifen therapy should be maintained and reached for a total duration of 10 years.
Patients with definite postmenopausal breast cancer should receive a total duration of 10 years of tamoxifen therapy or, after 5 years of adjuvant tamoxifen therapy, change to aromatase inhibitor therapy and continue for 5 years.
When patients are intolerant to tamoxifen or aromatase inhibitors and treatment is interrupted within 5 years, they should be replaced with another type of adjuvant endocrine therapy for up to 5 years.
Postmenopausal patients who have completed 5 years of tamoxifen therapy should continue tamoxifen or aromatase inhibitor therapy for 5 years and reach a total duration of 10 years of endocrine therapy.
Premenopausal or perimenopausal female patients, or those with unknown menstrual status, who have completed 5 years of adjuvant tamoxifen therapy should continue to receive tamoxifen therapy for 5 years.
Finally, different options are available for newly diagnosed postmenopausal patients with hormone receptor positive breast cancer: adjuvant therapy with an aromatase inhibitor as initiation therapy and maintenance for 5 years; adjuvant tamoxifen therapy for 10 years; adjuvant tamoxifen therapy given initially for 5 years and followed by an additional 5 years of AI therapy; adjuvant tamoxifen therapy for 2-3 years followed by AI therapy for up to 5 years and allowing adjuvant The total duration of hormone therapy was maintained at 7-8 years.
Breast cancer experts interviewed by MedPageToday were unanimous in their agreement with the ASCO guidelines, although it was felt that in some cases, further research may be needed.
The guidelines further confirm the effectiveness and general tolerability of adjuvant hormone therapy for hormone receptor-positive premenopausal and postmenopausal women with breast cancer, said Katherine H.R. Tkaczuk of the University of Maryland School of Medicine.
”I think the benefits of long-term hormone therapy outweigh the possible risks,” Tkaczuk said, “The major risks of long-term hormone therapy include increased incidence of pulmonary embolism and endometrial cancer, and the risk of ischemic heart disease is currently unclear, while the risk of stroke is similar between groups. “
”This guideline reflects the latest research evidence and suggests that when itamoxifen is used to prevent recurrence of primary breast cancer, it can simultaneously lead to long-term survival benefits for patients,” said Len Lichtenfeld, MD, of the ACSO committee, “Ultimately, in this case decision on which treatment is best to use should be communicated to the patient by the physician and discussed together.”
For all patients with hormone-receptor-positive breast cancer who have received 5 years of hormonal adjuvant therapy, all should receive further extended hormone therapy if there are no drug tolerance issues, according to Michaela J. Higgins, MD, a surgical resident at Massachusetts General Hospital.
”For premenopausal women with breast cancer who have been treated with tamoxifen for 5 years, there are data available that suggest such patients should continue tamoxifen for the next 5 years,” Higgins said, “but for postmenopausal women, or during tamoxifen treatment However, for postmenopausal women, or those who experience menopause during tamoxifen therapy, I recommend the aromatase inhibitor letrozole (Flon), which has been shown to have fewer side effects than tamoxifen.”
The current updated guidelines represent “an important advance in the treatment of patients with hormone receptor-positive breast cancer, especially for women facing this disease.” Virginia Borges, MD, of the University of Colorado Oncology Center, said.
”We’ve known for a long time that patients with estrogen-driven breast cancer are more likely to recur 5 years after diagnosis, and now we have new options regarding further preventive treatment, especially for younger female patients, and it moxifen remains an important option.”
Clinical judgment and patient-specific needs should also be taken into account in the decision making process. William Gradishar, MD, from Northwestern University in Chicago, believes.
”It is not a simple black-and-white relationship regarding treatment with tamoxifen, but must be considered individually for each patient,” Gradishar added. “Patient tolerability will limit the long-term use of the drug; for example, a premenopausal woman may become pregnant after five years of treatment, and the benefits and risks must be considered individually.”
Matthew Goetz, MD, of the Mayo Clinic, mentioned that “the benefits of extended treatment with itamoxifen appear to outweigh the possible risks, especially for premenopausal female patients, because of the significantly lower risk of serious side effects, such as blood clots and uterine cancer, in this population.”
Burstein said the study did not involve a conflict of interest and included other authors.