Clinical Advances in Hematology & Oncology

February 2019 - Volume 17, Issue 2

Highlights From the 2018 San Antonio Breast Cancer Symposium

T-DM1 Benefits Women With Residual Disease After Neoadjuvant Chemotherapy and Trastuzumab

Women who have residual disease after neoadjuvant chemotherapy and trastuzumab for early-stage human epidermal growth factor receptor 2 (HER2)–positive breast cancer benefit from treatment with trastuzumab emtansine (T-DM1; Kadcyla, Genentech) rather than standard treatment with further trastuzumab (Herceptin, Genentech), according to the phase 3 KATHERINE trial.

The trial was an open-label study of 1486 women with HER2-positive early-stage breast cancer. These patients had residual disease after receiving chemotherapy and HER2-targeted therapy before surgery. Within 12 weeks after surgery, the patients were randomly assigned to receive T-DM1 or trastuzumab for 14 cycles. 

Dr Charles Geyer and coinvestigators found that the rate of invasive disease–free survival at 3 years was 88.3% in the T-DM1 group and 77% in the trastuzumab group, an absolute improvement of 11.3 percentage points (P<.0001). In addition, the risk of developing an invasive disease–free survival event was significantly lower in the T-DM1 group than in the trastuzumab group, with a hazard ratio for invasive disease or death of 0.50 (95% CI, 0.39-0.64; P<.001).

Side effects of T-DM1 included drops in the platelet count, sensory neuropathy, and elevated liver enzymes. 

Additional follow-up is planned to determine the effect of adjuvant T-DM1 on overall survival. 

Low-Dose Tamoxifen Reduces Risk for Disease Recurrence and New Disease in Breast Intraepithelial Neoplasia

Low-dose tamoxifen reduces the risk for disease recurrence and new disease in women who have undergone surgery for breast intraepithelial neoplasia, according to results of the phase 3 TAM-01 trial. 

The study, led by Dr Andrea De Censi, included 500 women with ductal carcinoma, lobular carcinoma in situ, or atypical ductal hyperplasia who had undergone surgery and who had also received radiation if necessary. Patients were randomly assigned to receive 5 mg of tamoxifen per day or placebo for 3 years; standard treatment consists of 20 mg of tamoxifen per day for 5 years. 

After a median follow-up of 5.1 years, the rate of disease recurrence or new disease was significantly lower in the low-dose tamoxifen arm than in the placebo arm (5.5% vs 11.3%), a reduction of 52%. Serious adverse events occurred in 12 of the 253 patients in the tamoxifen arm and in 16 of the 247 patients in the placebo arm. No significant differences in menopausal symptoms were reported between the 2 arms. 

Oxybutynin Is Effective Treatment For Hot Flashes

Oxybutynin, an anticholinergic agent that is most commonly used to treat urinary incontinence, is an effective treatment for hot flashes, according to the results of a new study presented by Dr Roberto Leon-Ferre. 

The study enrolled 150 women who had experienced at least 28 hot flashes per week for more than 30 days. More than half (62%) of the women took tamoxifen or an aromatase inhibitor for the duration of the study. Women were randomly assigned to receive either 2.5 mg of oxybutynin twice a day for 6 weeks, 2.5 mg twice a day for 1 week followed by 5 mg twice a day for 5 weeks, or a placebo. 

According to self-administered evaluations, reductions in the hot flash score and in the frequency of hot flashes were significantly greater in patients in the 2 oxybutynin groups  than in those in the placebo group. The mean change in the hot flash score was –10.6 vs –5.7. 

Although patients taking oxybutynin were more likely than those taking placebo to experience side effects such as dry mouth, they were no more likely to discontinue the agent owing to adverse effects. 

Axillary Radiotherapy Remains Effective Alternative to Surgery at 10 Years

Recurrence and survival rates at 10-year follow-up after axillary radiotherapy continue to be comparable with those after axillary lymph node dissection (ALND), according to new data from the phase 3 AMAROS trial. Previously published data from this study were based on 5-year follow-up. 

Dr Emiel Rutgers and colleagues randomly assigned 1425 patients with early-stage, clinically node-negative breast cancer to axillary radiotherapy or ALND. After 10 years, no statistically significant differences between the rates of axillary recurrence, distant metastasis–free survival, and overall survival were seen in the 2 groups; however, a second primary cancer was more likely to develop in patients in the axillary radiotherapy group, in whom the incidence of contralateral breast cancer was higher.