How to recruit breast cancer patients for clinical trials at your site

How many breast cancer patients are diagnosed each year?

The American Cancer Society estimates 321,910 new cases of female breast cancer in the United States in 2026, out of 2,114,850 new cancer cases overall (American Cancer Society 2026). Breast cancer is one of the largest single sources of newly diagnosed oncology patients in the country.

A simple ratio puts the competition in perspective. The American Cancer Society reports 321,910 new female breast cancer cases expected in 2026. Divided across 923 recruiting studies, that is roughly 349 people per study nationally, before eligibility criteria, geography, and patient willingness cut the pool down. Most of those patients will never hear about a trial unless a physician brings it up.

How many breast cancer trials are recruiting in the United States right now?

As of October 6, 2026, ClinicalTrials.gov lists 923 breast cancer studies with a status of recruiting and at least one location in the United States (ClinicalTrials.gov). Of those, 763 are interventional trials and 160 are observational studies. Industry is the lead sponsor on 243 of them, about 26%. Academic centers, cooperative groups, and government sponsors run the rest.

Interventional breast cancer trials by phase:

The median interventional trial targets 96 participants in total across all of its sites. The typical industry funded trial lists 11 recruiting locations in the United States, so each site is usually expected to deliver a small slice of that total, and sponsors notice quickly which sites deliver none.

Where are breast cancer trials concentrated?

Every location on every recruiting study counts here. Together the 923 studies list 15,272 recruiting US locations. These states host the most recruiting studies:

The most frequently listed institutions include Dana Farber Cancer Institute, Massachusetts General Hospital, Memorial Sloan Kettering Cancer Center, and Washington University School of Medicine. The industry sponsors with the most recruiting breast cancer trials right now include AstraZeneca, Eli Lilly and Company, Roche, Merck Sharp & Dohme, and Novartis Pharmaceuticals. If your site sits in one of the top states, you are recruiting from the same patient population as several large academic programs at once, and the patients who reach you will mostly come through the physicians who already treat them.

Which physicians see breast cancer patients first?

Breast cancer patients move through a predictable chain: screening and primary care, breast imaging, surgical consultation, then medical and radiation oncology. Each step is a referral point. The AAMC counts 18,612 active hematology and oncology physicians in the United States (AAMC 2024 via Becker's), and most breast cancer trial patients are under the care of one of them or a breast surgeon when they become eligible.

• Medical oncologists, for metastatic, adjuvant, and neoadjuvant treatment studies.
• Breast and surgical oncologists, who see newly diagnosed patients before treatment decisions are final, which is when neoadjuvant studies need them.
• Radiation oncologists, for radiotherapy and combined modality studies.
• Gynecologists and primary care physicians, for prevention, screening, and survivorship studies.

What decides eligibility in breast cancer trials?

Most breast cancer protocols are written around tumor biology and treatment history: hormone receptor and HER2 status, stage, the number and type of prior therapies, and time since the last treatment. A referring oncologist already has every one of those facts in the chart. Putting them at the top of your study summary lets the physician match a patient in seconds instead of guessing, which matters because screen failures are expensive. Tufts CSDD puts the average screen failure rate across Phase 2 and 3 trials at 36.3% (Tufts CSDD).

Why physician referral matters more than volume

A large patient population does not fill trials on its own. Physicians refer a median of about five patients into clinical trials per year, which is less than 0.2% of their annual patient volume (Getz, Applied Clinical Trials). In Tufts CSDD research, physicians and nurses named lack of access to study information and lack of time as the main reasons they do not refer, and physicians in clinical practice were 2.7 times more likely to refer than physicians in hospital settings (Tufts CSDD via Applied Clinical Trials).

That is the gap a site can close. The physicians who diagnose and manage your study population already know which patients are likely to qualify. They need a short, specific summary of your open study, a named coordinator, and a reason to believe the patient will come back to them.

A practical breast cancer referral plan for your site

1. Pull the live ClinicalTrials.gov list for your state and note which competing studies are enrolling the same population within driving distance of your site.
2. List the medical oncologists, breast surgeons, and radiation oncologists within a realistic drive of your site. Community practices come first.
3. Send each physician a one page study summary: the diagnosis, the two or three criteria that decide most eligibility, what the patient will experience, and the coordinator's direct line.
4. Follow up by email and LinkedIn, and call the practices that engage.
5. Report back to the referring physician on every patient, whether or not the patient enrolls.

See how to get physicians to refer patients and the referral letter guide for templates.