Stay Up
to Date
Stay Up
to Date
Breaking News,
Updates, & More
Breaking News,
Updates, & More
Click Here to
Subscribe
Click Here to
Subscribe

5 mg Tamoxifen as Effective as 20 mg Daily in Early Localized Breast Cancer

TON - February 2019, Vol 12, No 1 - Breast Cancer
Phoebe Starr

The large, randomized TAM-01 clinical trial demonstrated that 5 mg daily of tamoxifen for 3 years halved the risk for recurrence of breast intraepithelial neoplasia—atypical ductal hyperplasia, ductal carcinoma in situ (DCIS), and lobular carcinoma in situ—in women after surgery and reduced the risk for new contralateral breast cancer by 75% compared with placebo.

The reduction in the risk for recurrent or new breast cancer is in line with results achieved with the use of tamoxifen 20 mg daily for 5 years, which has been the standard treatment (with or without radiation) in this setting.

“Tamoxifen 20 mg per day has troublesome side effects, including endometrial cancer, deep-vein thrombosis, and menopausal symptoms, which pose a barrier to adherence for prevention. We hypothesized that a much lower dose given for shorter duration was as effective as, and less toxic, than standard tamoxifen,” said lead investigator Andrea De Censi, MD, Director, Medical Oncology Unit, National Hospital E.O. Ospedali Galliera, Genoa, Italy, at the 2018 San Antonio Breast Cancer Symposium.

“Our data show that in a randomized trial, low-dose tamoxifen was effective…without causing significant serious adverse events or any increase in menopausal symptoms,” he said. “Therefore, we strongly believe that these data are practice-changing.”

The study randomized 500 women with atypical ductal hyperplasia, DCIS, or lobular carcinoma in situ after surgery, with or without radiation, to low-dose tamoxifen for 3 years or to placebo. The patients were seen every 3 months and had an annual mammogram.

“We did not compare it with 20 mg per day of tamoxifen, because the cost would be prohibitive on our limited budget from nonprofits and the government,” Dr De Censi explained.

The TAM-01 Study Results

At a median follow-up of 5 years, 14 (5.5%) of the 253 patients in the low-dose tamoxifen arm versus 28 (11.3%) of the 247 patients in the placebo arm had breast cancer recurrence or new breast cancer. Thus, low-dose tamoxifen reduced the risk for new or recurring disease by 52% compared with placebo.

Among patients with a contralateral breast cancer recurrence or new disease, 3 of the 14 women in the tamoxifen arm and 12 of the 28 women in the placebo arm had invasive breast cancer, and 11 and 18 women, respectively, had breast intraepithelial neoplasia.

“The decrease in contralateral breast cancer events was based on only 15 events, so we need to be cautious,” Dr De Censi stated.

A total of 12 serious adverse events were reported in the low-dose tamoxifen arm versus 16 events in the placebo arm. Only 1 deep-vein thrombosis or pulmonary embolism occurred in each arm, and 1 case of endometrial cancer was reported in the low-dose tamoxifen arm.

Low-dose tamoxifen did not substantially increase tamoxifen-associated side effects. Based on patient self-reports, an increase in hot flashes in the tamoxifen group versus the placebo group was of borderline significance, “amounting to about 1 extra hot flash per day,” Dr De Censi said. No differences were found between the treatment arms in the rates of vaginal dryness, painful sexual intercourse, and musculoskeletal events.

“Our results have external validity and are generalizable. Tamoxifen 10 mg every other day is applicable in clinical practice from tomorrow on,” Dr De Censi stated, adding that tamoxifen is available in 10-mg tablets only. “You can cut the tablet in half starting tomorrow,” he told listeners.

“I would definitely give lower doses of tamoxifen to the ADH [atypical ductal hyperplasia] and LCIS [lobular carcinoma in situ] patients, and if I have a DCIS patient who is not tolerating the 20-mg dose, I would be extremely happy to give that patient 5 mg per day,” said Virginia Kaklamani, MD, Leader, Breast Cancer Program, UT Health San Antonio M.D. Anderson Cancer Center, San Antonio, TX, who commented on the study.

Related Items
Sitravatinib, Novel TKI, plus Nivolumab Elicits Good Responses in Renal-Cell Carcinoma
Phoebe Starr
TOP - May 2020, Vol 13, No 3 published on May 21, 2020 in Emerging Therapies
First-in-Class Oral MK-6482 Shows Exciting Results in Clear-Cell Renal-Cell Carcinoma
Phoebe Starr
TOP - May 2020, Vol 13, No 3 published on May 21, 2020 in Emerging Therapies
PSMA-PET Scanning Is Wave of the Future in Prostate Cancer
Phoebe Starr
TON - April 2020, Vol 13, No 2 published on April 16, 2020 in Prostate Cancer
SBRT plus Immunotherapy in Metastatic Renal-Cell Carcinoma Warrants Further Study
Phoebe Starr
TON - April 2020, Vol 13, No 2 published on April 16, 2020 in Renal-Cell Carcinoma
Targeted Therapy with Olaparib Beneficial in Metastatic Prostate Cancer with Gene Mutations
Phoebe Starr
Web Exclusives published on February 24, 2020 in ESMO
Postsurgery Observation Better Than Radiotherapy in Men with Prostate Cancer
Phoebe Starr
TON - February 2020, Vol 13, No 1 published on February 5, 2020 in ESMO
Real-World Healthcare Utilization and Costs Support Broader Use of CAR T-Cell Therapy
Phoebe Starr
TON - February 2020, Vol 13, No 1 published on February 5, 2020 in Value-Based Care
Long-Term Data Confirm Survival Benefit for Pembrolizumab in Advanced NSCLC
Phoebe Starr
Web Exclusives published on November 25, 2019 in Lung Cancer
Adding CDK4/6 Inhibitor to Endocrine Therapy Improves Survival in Advanced Breast Cancer: New Standard of Care
Phoebe Starr
Web Exclusives published on October 28, 2019 in ESMO, Breast Cancer
Vincristine, Racial Disparities in Multiple Myeloma, and HER2 Metastatic Breast Cancer Are in the News
Web Exclusives published on October 22, 2019 in Breast Cancer, FDA Updates, In the News, Multiple Myeloma, Pediatric Cancer
Last modified: April 27, 2020