Published on
Updated
Reading 3 mins.
Adding targeted therapy to hormone therapy has shown real progress for some early-stage breast tumors. Presented at the ASCO 2023 congress, this advance concerns the most frequent breast cancers.
Hormone-dependent breast cancer accounts for approximately two-thirds of breast cancers. It is more common after menopause. The authors of this new study point out that one third of people with hormone-dependent, HER2-negative stage II disease experience a recurrence after the standard treatment and more than half of people with stage III disease experience a recurrence. And if a recurrence occurs, it is often at a more advanced stage.
To prevent these recurrences, hormone therapy is introduced after surgery. It is called adjuvant, its duration is 5 to 10 years. Several studies have shown that the longer the hormonal treatment, the lower the risk of recurrence, even if the side effects of this treatment remain difficult for some women to manage. Today, a new compound could improve the management of these women.
Use targeted therapy at early stages
“Currently approved targeted therapies can only be used in a small population of patients diagnosed with HR-positive, HER2-negative early breast cancer, leaving many without an effective treatment option to reduce the risk of cancer recurrence“said lead author Prof. Dennis J. Slamon, director of research at UCLA Jonsson Comprehensive Cancer Center in Los Angeles, California.
Ribociclib (marketed as Kisqali © is a targeted therapy called a small molecule inhibitor, which works by targeting proteins in breast cancer cells called CDK4 and CDK6, which modulate cell growth. This molecule is already used to treat breast cancer. HR-positive, HER2-negative advanced or metastatic breast cancer in combination with hormone therapy.
Now researchers want to know if it can be helpful at an early stage, including when dealing with cancer that hasn’t yet spread to the lymph nodes. To answer this question, a vast study has just delivered its results.
A risk of recurrence reduced by 25%!
Study participants were randomly assigned to receive either adjuvant ribociclib for 3 years with hormone therapy for at least 5 years, or hormone therapy alone.
For patients receiving ribociclib, the most common side effects were neutropenia (low white blood cell count) and joint pain. Rates of gastrointestinal adverse events and fatigue remained low. For patients receiving hormone therapy alone, the most common side effects were joint pain and hot flushes.
Results: Overall, the addition of ribociclib reduced the risk of recurrence by 25%. It also showed more favorable results in terms of overall survival, recurrence-free survival (time without disease reappearing) and distant disease-free survival (time without disease reappearing in another organ).
Towards new treatment standards?
“Although early, these results are very promising and suggest that there will be a role for ribociclib as an adjuvant in stage II and higher hormone receptor-positive (HR-positive) and HER2-negative breast cancer.“, declared Pr. Rita Nanda, expert of the ASCO. This study confirms the interest of this targeted therapy for earlier cancers and could therefore change the care of very many women. Extensions of authorization marketing of this drug could soon take place.
More generally, targeted therapies long reserved for the most advanced forms tend to demonstrate their interest at earlier stages of cancer. For this, vast studies making it possible to trace a line of treatment (from the most serious cancers to the earliest cancers) must be conducted to demonstrate the benefits of such a strategy and the absence of prohibitive side effects ( benefit/risk balance). This would imply an increasingly strong personalization of treatments, whatever the tumor and the stage of advancement of the cancer.