OVARIAN SUPPRESSION REDUCES RECURRENCE FOR YOUNG PATIENTS

Ovarian Suppression Reduces Recurrence for Young Breast Cancer Patients

Follow-up results of the TEXT and SOFT clinical trials have shown exemestane plus ovarian function suppression provide significant improvements in disease-free survival and preventing breast cancer recurrence for premenopausal women with hormone receptor-positive breast cancer.

The TEXT and SOFT trials are phase III, randomised clinical trials that enrolled 2,672 and 3,066 premenopausal women worldwide, with hormone receptor-positive early breast cancer, including 249 and 240 women in Australia and New Zealand respectively. The trials produced practice changing results in the treatment of breast cancer in young women and showed that the aromatase inhibitor, exemestane, is more effective than tamoxifen in preventing breast cancer recurrence in young women who also receive ovarian function suppression.

At the 2017 San Antonio Breast Cancer Symposium results of the combined analysis of the TEXT and SOFT studies, with a median follow-up of 9 years, confirmed statistically significant improvements in disease outcomes with exemestane versus tamoxifen used in combination with triptorelin ovarian suppression. Adjuvant exemestane plus ovarian function suppression, compared with tamoxifen plus ovarian function suppression, showed sustained absolute improvements in disease-free survival and freedom from distant recurrence of 4.0% and 2.1% at 8 years, respectively. The majority of patients had HER2-negative tumors (86% of the population) and had clinically-meaningful benefits, especially those patients deemed at sufficient risk of recurrence to receive adjuvant chemotherapy, for whom the absolute improvements in disease-free survival were 7% – 9%, and absolute improvements in freedom from distant recurrence were 5% – 7%, across TEXT and SOFT respectively. No difference in overall survival after 9 years median follow-up was observed. No new safety concerns were detected.

For the SOFT study, adding ovarian function suppression to tamoxifen significantly decreased the relative risk of disease-free survival events by 24% versus tamoxifen-alone (hazard ratio [HR]=0.76 (95% confidence interval [CI] 0.62-0.93), P=0.009) in the overall population after 8 years median follow-up, resulting in a 4.2% absolute benefit at 8 years. Furthermore, the clinical benefit was particularly clear in women under age 35, with a relative risk reduction of 44% (HR=0.66 (95% CI 0.41-1.07)) corresponding to an 8.7% absolute benefit at 8 years. A small overall survival benefit was seen, being more evident in women who remained premenopausal after receiving adjuvant chemotherapy. The speakers stressed the critical importance of long-term follow-up of these young women, and follow-up of the over 5700 participants continues.

“To optimally translate the absolute improvements seen in the trial populations into clinical practice, oncologists need to discuss and weigh potential benefits and toxicity with each individual premenopausal patient with hormone-receptor positive breast cancer,” Associate Professor Francis concluded in her presentation at San Antonio.

Associate Professor Prue Francis chaired the International Steering Committee responsible for the TEXT and SOFT clinical trials and is the Chair of the Breast Cancer Trials Scientific Advisory Committee. The TEXT and SOFT trials are led by the International Breast Cancer Study Group (IBCSG) and were conducted in Australia and New Zealand by Breast Cancer Trials.

Breast Cancer Trials is the largest, independent, oncology clinical trials research group in Australia and New Zealand. For 40 years, BCT has conducted a national clinical trials research program for the treatment, prevention and cure of breast cancer. For more information about BCT, visit www.breastcancertrials.org.au.

To organise an interview with Associate Professor Prue Francis, please contact: Anna Fitzgerald, Breast Cancer Trials Communications Manager 0400 304 224 or anna.fitzgerald@bctrials.org.au