Oleg Gluz, MD, West German Study Group, Moenchengladbach, Germany, shares results from the phase 3 ADAPTcycle trial. In this analysis, the impact of age, recurrence score (as determined by Oncotype DX), biological markers, and ovarian function suppression on response to short preoperative endocrine therapy was investigated among patients with HR-positive, HER2-negative breast cancer.

Dr Gluz concluded, “These data could help a much larger proportion of younger women to spare chemotherapy in future, in combination with lower Ki-67 and low Recurrence Score, for example, Recurrence Score below 25. This may have huge impact on the clinical practice in the future.”

These results were first presented at the 2023 San Antonio Breast Cancer Symposium

Transcript:

My name is Oleg Gluz. I am one of the scientific coordinators and leaders of the WSG from Western Germany, and we are today at the San Antonio Breast Cancer Symposium in Texas. It will be my pleasure today to present the data from the screening cohort of the ADAPTcycle trial.

In early hormone receptor-positive, HER2-negative breast cancer, there is one very important question which remains unclear: the optimal treatment in younger patients and premenopausal patients who are candidates for adjuvant chemotherapy and who are candidates for endocrine therapy alone. And in the ADAPTcycle trial, we have performed so-called induction endocrine treatment, endocrine treatment given for 2 to 4 weeks before the surgery or second core biopsy, and we looked at Ki-67 decrease after short term of preoperative endocrine treatment. And we know that the lower Ki-67 after endocrine treatment is associated with improved prognosis.

In combination with genomic testing, with Oncotype DX test, we have shown already in our previous ADAPT trials in patients with lower Ki-67 and Recurrence Score below 25 and up to 3 positive lymph nodes, even in case of younger patients, these patients did very well also without chemotherapy. And now we have looked more deeply in the ADAPTcycle trial, at about 5,000 patients screened in Germany, and we're looped off about 4,200 patients with all available data. We have observed two very interesting things.

The first one, if we have added ovarian function suppression, like goserelin [Zoladex] once a month, to the preoperative endocrine treatment, we have increased numbers of patients who had low post endocrine ki-67, twice as many. So compared 30% after tamoxifen alone, compared to up to 70% in patients treated in combination with ovarian suppression. And these data are very interesting because these data could help a much larger proportion of younger women to spare chemotherapy in future, in combination with lower Ki-67 and low Recurrence Score, for example, recurrence score below 25. This may have huge impact on the clinical practice in the future. This was the first thing.

And the second thing is also very interesting. If you look at patients with higher Recurrence Score, all patients will be treated by adjuvant chemotherapy now in the clinical routine. We have observed that if we use optimal endocrine treatment —for example, aromatase inhibitors in older women or combination of aromatase inhibitors plus ovarian function suppression in younger women— we have observed up to 50% of all patients are endocrine responders even in case of higher genomic risk. And this may be also very interesting in the future trials.

This is also the aim of the ADAPTcycle trial, to look at what may be the optimal treatment for these patients. To give chemotherapy as is done now in the clinical routine, or to give, for example, intensified endocrine treatment, combined endocrine treatment with CDK4/6 inhibitors, like ribociclib. This may have huge impact on the clinical routine in the future for these patients, not for now.

But for now, it may be very important also to look at the clinical routine: who are the patients who have endocrine sensitive tumor, after optimal endocrine treatment measured very easily, by ki-67 in combination with clinical risk and in combination with genomic risk, it's already done in most countries in the Western world, in the US, and also in Europe.

Source:

Gluz O, Christgen M, Nitz U, et al. Impact of age and ovarian function suppression (OFS) on endocrine response to short preoperative endocrine therapy (ET): Results from the multicenter ADAPTcycle trial (n=4,334). Presented at San Antonio Breast Cancer Symposium; December 5-9, 2023; San Antonio, Texas. Abstract LBO1-05