Clinical trials · California
Early Breast Cancer clinical trials in California
We’re tracking 44 recruiting early breast cancer studies with a site in California — including Phase 1, Phase 1/Phase 2, Phase 2 and Phase 3 studies, each written for real people, not researchers.
Recruiting studies in California
- NCT04603209Recruiting
Check-in registry for radiation during breast-conserving surgery
This registry study tracks people with early-stage, single-area breast cancer to understand outcomes when radiation is given during breast-conserving surgery. It may help doctors improve treatment planning for patients like you.
Santa Monica, CaliforniaAges 18 years+ - NCT07690852Recruiting
Environmental exposures and breast cancer risk study
This study looks at how environmental exposures might affect breast cancer risk. It includes women at average risk, high risk, or those diagnosed with breast cancer before age 50, as well as healthcare providers.
Duarte, CaliforniaAges 18 years+ - NCT07629206Recruiting
Freezing therapy for small, early-stage breast cancer
This study tests whether freezing a small breast tumor (cryoablation) is a safe and effective treatment option for older adults with early-stage, hormone-receptor-positive breast cancer. Instead of surgery, the goal is to destroy the tumor by freezing it in place.
Glendale, CaliforniaAges 70 years+ - NCT07541079RecruitingPhase 3
Testing a New Breast Cancer Drug for Women Who Can't Tolerate Current Therapy
This study tests giredestrant, a new hormone-blocking medication, in postmenopausal women with early-stage ER+ breast cancer who have experienced intolerable side effects from their current aromatase inhibitor therapy. The trial will measure how well you tolerate this new drug and how it affects your quality of life.
Fountain Valley, CaliforniaAges 18 years+ - NCT07401381RecruitingPhase 1
Injectable vs. oral letrozole in early breast cancer
This study compares a new injectable form of the drug letrozole with the standard oral pill. It aims to find out if the injection works as well as the pill for women who have already taken letrozole for their early breast cancer and have finished their initial treatment.
Beverly Hills, CaliforniaAges 18–80 - NCT07287098RecruitingPhase 2
Imlunestrant for premenopausal women with ER+/HER2- early breast cancer
This trial tests a new hormone-blocking pill (imlunestrant) in premenopausal women with early-stage ER+/HER2- breast cancer. Depending on whether you've had prior hormone therapy, the study will see if this treatment works better than standard options.
Duarte, CaliforniaAges 18 years+ - NCT07211178Recruiting
Tracking cancer DNA in blood to detect early return of breast cancer
This study tracks tiny traces of cancer DNA in the blood over time to see if it can find early signs of breast cancer coming back. It looks at different types of breast cancer and at different points in a patient's treatment journey.
Whittier, CaliforniaAges 18–99 - NCT07054190RecruitingPhase 2
Testing inavolisib for early-stage PIK3CA-mutated breast cancer
This study tests a new drug called inavolisib for people with early-stage breast cancer that has a specific genetic change (PIK3CA mutation). The goal is to see if adding this drug to standard hormone therapy is safe and effective before surgery.
Los Angeles, CaliforniaAges 18 years+ - NCT07017673RecruitingPhase 2
Ivonescimab with chemo for early-stage triple negative breast cancer
This trial tests a new drug, ivonescimab, combined with standard chemotherapy before surgery for people with high-risk early-stage triple negative breast cancer. The goal is to see if adding this drug improves treatment response.
Los Angeles, CaliforniaAges 18 years+ - NCT06876714RecruitingPhase 3
Shorter vs Longer HER2 Therapy for Breast Cancer with Complete Response
This trial compares 6 months versus 12 months of HER2-targeted therapy for people with HER2+ breast cancer who had a complete response after chemo and trastuzumab. The goal is to see if a shorter treatment is just as effective.
Arroyo Grande, CaliforniaAges 18 years+ - NCT06797635RecruitingPhase 2
Study of Patritumab Deruxtecan and Pembrolizumab for High-Risk Early Breast Cancer
This trial tests a combination of targeted therapies (patritumab deruxtecan plus pembrolizumab) along with other anticancer drugs for people with a high-risk type of early-stage breast cancer that is either triple-negative or has very low hormone receptors and is HER2-negative. The goal is to see if this approach can help prevent the cancer from coming back.
Santa Monica, CaliforniaAges 18 years+ - NCT06492616RecruitingPhase 3
Elacestrant versus standard hormone therapy for early breast cancer
This trial compares a new medicine, elacestrant, to the usual hormone therapy for people with early-stage breast cancer that is hormone receptor-positive and HER2-negative, and who have a high chance of it coming back. The goal is to see if elacestrant works better at preventing the cancer from returning.
Bakersfield, CaliforniaAges 18 years+ - NCT06445738Recruiting
Can some women safely skip radiation after breast cancer surgery?
This trial is for women 50 and older with early-stage, hormone-positive or HER2-positive breast cancer. It tests whether it is safe to skip radiation therapy after a lumpectomy if an MRI before surgery shows the breast tissue looks a certain way.
San Francisco, CaliforniaAges 50 years+ - NCT06224673RecruitingPhase 2
Testing ARX788 for HER2-low advanced breast cancer
This trial tests a new drug, ARX788, for people with HER2-low breast cancer that has spread or cannot be removed by surgery. The goal is to see if ARX788 helps shrink or control the cancer.
San Francisco, CaliforniaAges 18 years+ - NCT06113016RecruitingPhase 2
Preventing frailty with fisetin and exercise in breast cancer survivors
This study tests whether adding a supplement called fisetin to an exercise program can help prevent frailty in women who have finished chemotherapy for early-stage breast cancer. If you are postmenopausal, have completed chemo within the last year, and can walk a certain distance, you may qualify.
Alhambra, CaliforniaAges Any age - NCT05929768RecruitingPhase 3
Shorter chemo plus immunotherapy without anthracyclines for early TNBC
This Phase 3 trial tests whether a shorter course of chemotherapy plus immunotherapy can work as well as standard treatment for early-stage triple-negative breast cancer. It avoids anthracycline drugs and may help reduce exposure to those medicines if the shorter plan is effective and safe.
Walnut Creek, CaliforniaAges 18 years+ - NCT04553770RecruitingPhase 2
Trastuzumab deruxtecan with or without anastrozole for early breast cancer
This Phase 2 study tests whether trastuzumab deruxtecan alone or combined with anastrozole can control early-stage breast cancer that is HER2-low and hormone-receptor positive. It aims to improve outcomes after initial surgical treatment by targeting cancer cells that may have low levels of HER2.
Fullerton, CaliforniaAges 18 years+ - NCT05827081RecruitingPhase 3
Ribociclib plus endocrine therapy for early breast cancer
This trial studies whether adding ribociclib to standard hormone (endocrine) therapy lowers the risk of breast cancer coming back in early-stage, hormone-receptor–positive cancer. It mainly looks at safety and how well the treatment controls cancer after surgery and (sometimes) prior hormone treatment.
Beverly Hills, CaliforniaAges 18–100 - NCT05812807RecruitingPhase 3
Pembrolizumab versus monitoring after triple-negative breast cancer response
This trial checks whether giving pembrolizumab (an immunotherapy) after surgery helps people with triple-negative breast cancer reduce the chance of the cancer coming back, compared with close monitoring only. It’s for patients who had no remaining invasive cancer after neoadjuvant chemotherapy plus pembrolizumab.
San Jose, CaliforniaAges 18 years+ - NCT05774951RecruitingPhase 3
Camizestrant for hormone-positive, HER2-negative early breast cancer
This trial tests camizestrant, a medicine that blocks estrogen signaling, to help prevent hormone-positive, HER2-negative early breast cancer from coming back. You may be eligible if your cancer has higher- or intermediate-risk features and you already completed at least 2 years of hormone therapy.
Anaheim, CaliforniaAges 18–130 - NCT05595499RecruitingPhase 2
Fisetin for better walking and strength in breast cancer survivors
This study tests whether fisetin (a natural compound) can improve physical function, like walking ability, in breast cancer survivors who feel frail. It may help strengthen muscles and improve daily activity after treatment.
Alhambra, CaliforniaAges Any age - NCT05524584RecruitingPhase 2
Anastrozole, fulvestrant, and abemaciclib for hormone-positive breast cancer
This trial tests whether combining three medicines can better control hormone-receptor–positive, HER2-negative metastatic breast cancer that cannot be cured with surgery or radiation. It may help shrink tumors and slow disease growth compared with standard hormone therapy approaches.
Orange, CaliforniaAges 18 years+ - NCT05455619RecruitingPhase 1/Phase 2
Targeted drugs for PI3K-altered, HR+/HER2- breast cancer
This Phase 1/2 trial tests how well a combination of targeted medicines works for advanced or returning HR+/HER2- breast cancer that has a PI3K pathway change (such as PIK3CA, PTEN, or AKT1). It may help by blocking growth signals in the cancer and is especially for people whose cancer has progressed after hormone therapy and a CDK4/6 inhibitor.
Loma Linda, CaliforniaAges 18 years+ - NCT05366881Recruiting
Blood test study to spot early cancer signal and cancer leftovers
This observational study checks whether a blood test (a “cfDNA” test) can detect early signs of cancer or small amounts of cancer left after treatment. It may help doctors use a simple blood sample to improve cancer detection and follow-up.
Duarte, CaliforniaAges 40 years+
Early Breast Cancer trials by city in California
Where these studies are running in California
Institutions with a site for the recruiting early breast cancer studies listed above.
- City of Hope · 7 studies
- Cedars-Sinai Cancer - Tarzana · 3 studies
- Cedars-Sinai Medical Center · 3 studies
- Huntington Memorial Hospital · 3 studies
- Loma Linda University Medical Center · 3 studies
- Mercy Cancer Center - Elk Grove · 3 studies
- Mercy Cancer Center - Rocklin · 3 studies
- Mercy Cancer Center - Sacramento · 3 studies
What taking part in a early breast cancer study involves
A screening visit first
Before anything else, the study team checks whether you fit — usually a visit with some tests. You can stop at any point, and screening is typically free.
Care at a nearby site
Study visits happen at a clinic or hospital taking part. Many studies cover the cost of the study treatment and related visits, and some reimburse travel.
You stay in control
Taking part is voluntary and you can leave a study at any time, for any reason, without affecting your regular care.
The team decides eligibility
Our fit check is a helpful first read, not a decision. The study team makes the final call after reviewing your health history.
Early Breast Cancer trials in other states
Common questions
- Are there early breast cancer clinical trials in California?
- Yes. We're currently tracking 44 recruiting early breast cancer studies with a site in California, each rewritten in plain language so you can see what it's testing and who it's for.
- How do I find out if I qualify for a early breast cancer study in California?
- Each study lists its eligibility rules — age, diagnosis, prior treatments. On every trial page we explain these in plain language and offer a short, optional pre-screen for a fit read. The study team makes the final decision.
- Do I have to live in California to take part?
- Not necessarily. These studies have a site in California, but eligibility is about your health, not your address — some people travel to take part, and a few studies reimburse travel. The study team can tell you what's required.
- Does it cost anything to join a early breast cancer trial?
- Using Clin2 is always free. Many trials cover the study treatment and related visits; some reimburse travel. The study team explains exactly what's covered before you decide.
Not the right time?
New early breast cancer studies open in California regularly. Set up a health profile and we’ll quietly watch for studies that fit you and email you when one opens.
Clin2 helps you find and understand clinical trials and does not provide medical advice. Study data comes from ClinicalTrials.gov. Talk with your doctor about whether a specific trial is right for you.