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Breast cancer starts when cells in the breast grow out of control, usually in the milk ducts or milk glands. Most cases are found as a lump, a change on a mammogram, or a change in the skin or nipple, and usually cause no pain early on. About 321,900 women will be diagnosed in the US in 2026. Men get it too, about 2,670 a year. Most people are diagnosed around age 63, but incidence is rising fastest in women under 50.
The key thing about modern treatment: it depends on the tumor's biology, tested from the biopsy. Most breast cancers are fueled by hormones and treated with medicines that block them. Some are HER2 positive, driven by a growth protein, and treated with targeted antibodies. Others are triple negative, meaning none of those drivers apply, once limited to chemotherapy, now also treated with immunotherapy. Because each type needs different drugs, almost every clinical trial enrolls one specific type, so knowing yours from the pathology report is what tells you which studies fit. More than 4.3 million women in the US are living after a breast cancer diagnosis today.
Trials by subtype. Most treatment studies enroll one biology: hormone receptor positive, HER2 positive, or triple negative. Within hormone positive disease, many now also require a specific mutation, such as PIK3CA or ESR1, found by a tumor or blood test. Study titles almost always name the subtype up front.
Early stage and prevention of recurrence. These test whether adding or changing a medicine before or after surgery lowers the chance the cancer returns. Because most early breast cancer is cured, these trials are large and long, and some test whether treatment can be safely shortened rather than lengthened.
Metastatic disease. Trials for cancer that has spread test new targeted drugs, antibody drug conjugates, and combinations, and increasingly compare a new medicine directly against today's standard rather than against placebo. Many enroll people whose current treatment has stopped working.
Screening and detection. Studies of artificial intelligence reading mammograms, blood based tests, and imaging for dense breasts. These often enroll healthy women, and they matter because finding cancer earlier is still the biggest single driver of survival.
Vaccines and immunotherapy. HER2 targeted vaccines and immune based approaches are in early trials, aiming to prevent recurrence or treat disease the immune system currently ignores.
Access, side effects, and survivorship. Studies of care navigation for underserved communities, of managing hormone therapy side effects so people can stay on it, and of long term health after treatment. These often have the widest eligibility.
Breast cancer trials sort people by four things from the pathology report and scans. The subtype: hormone receptor status, HER2 status, and increasingly a specific mutation like PIK3CA, ESR1, or an inherited BRCA change. The stage: early (stage I to III) versus metastatic (stage IV), and within early disease, whether you are before or after surgery. The treatment history: many metastatic trials want people whose cancer progressed on a particular class of drug, while early stage trials often want people who have not started treatment yet. And overall health, including heart function, since some breast cancer medicines affect the heart. Screening studies enroll women with no diagnosis at all, and survivorship and navigation studies often accept anyone who has had breast cancer. Men with breast cancer are eligible for many studies, though not all. Eligibility always varies by study.
Partly. About 5 to 10 percent of cases are linked to an inherited gene change, most often BRCA1 or BRCA2. Having a mother, sister, or daughter with breast cancer roughly doubles risk. But most women with breast cancer have no family history, and most with a family history never develop it.
Breast cancer is staged 0 to IV using tumor size, lymph node involvement, and spread, and since 2018 the stage also factors in the tumor's biology and grade.
Stage 0. Ductal carcinoma in situ: abnormal cells confined to the milk ducts. Not invasive, nearly always cured, and the subject of trials asking whether some cases can be safely watched rather than treated.
Stage I. A small invasive tumor, no or minimal lymph node involvement. Five year survival is above 99 percent for localized disease.
Stage II and III. Larger tumors or spread to nearby lymph nodes, sometimes to the chest wall or skin. Treatment usually combines surgery, radiation, and drug therapy, often given before surgery to shrink the tumor. Most trials of new early stage treatments enroll here.
Stage IV. Metastatic: spread to distant organs, most often bone, liver, lungs, or brain. Not curable today, but treatable for years, and the stage where most new drug approvals and trials are concentrated. Five year survival for distant disease has roughly doubled since the 1990s.
Study titles say "early stage," "locally advanced," or "metastatic" and name the subtype. Your stage and your receptor status from the pathology report tell you at a glance which studies fit.
Enrolling in a breast cancer study through our platform takes about 5 minutes. Here is how it works:
Identify your trial. Use the search bar or filters. Breast cancer study titles are precise: they name the subtype (HER2 positive, hormone receptor positive, triple negative), the stage (early, locally advanced, metastatic), and often a mutation. Match those to your pathology report and most studies rule themselves in or out from the title.
Select your preferred location. Enter your city or state in the filter on the left. Drug trials involve regular infusions, scans, and blood work at a cancer center, so distance matters. Screening, navigation, and survivorship studies are often closer to home or remote.
Explore study details. Click "Learn More" for goals, procedures, and eligibility, including which prior treatments are required or excluded, whether a fresh biopsy or genetic test is needed, and how visits are scheduled.
Complete the health profile. Click "Get started" to begin the 5-step application. Have three things ready: your receptor status (ER, PR, HER2) and any mutation results, your stage, and the list of treatments you have had so far. Those three answers decide eligibility for nearly every breast cancer study.
Submit the application. A clinical trial coordinator reviews it and contacts you about whether you may qualify. Nothing is decided until you have gone through informed consent, and participation is voluntary at every step. Your oncologist stays involved throughout.