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Katie Thurston's Stage 4 Breast Cancer: What It Means
Katie Thurston shared that breast cancer had spread to her liver. Learn what metastatic breast cancer means, how it is tested, and why treatment is individual.
Original commentary from the Cancer Explained editorial team.
Please note: this page is educational only — it is not medical advice, and it does not speculate about anyone’s health beyond reliable public reporting. For questions about your own health, talk with your healthcare team.
What she has said, and when
Katie Thurston announced a breast cancer diagnosis in an Instagram post on February 15, 2025. She was 34. ABC News reported the post two days later.
On March 28, 2025, she posted again to say the cancer had spread to her liver, making it stage 4. NBC News reported her words: the spots were "fairly small; however, that does put me at Stage 4." She said treatment would begin on April 4 and would include chemotherapy.
In an interview with Good Morning America broadcast on October 16, 2025, she said a six-month scan had shown the medicine was still working and the tumor was still shrinking.
Those dates matter. This page reports what she said on the days she said it. It does not describe her health now, and no page should claim to.
How the stage 4 finding came about
Her account of the testing sequence is a useful map of how this works.
She described a breast ultrasound, a mammogram, and a biopsy of the breast. Then came a CT scan, a bone density scan, and an MRI. After transferring her care from Los Angeles to New York, she had a PET scan, which found spots on her liver that looked, in her words, "a little suspicious."
That progression is standard. Imaging finds something; a biopsy establishes what it is; further scans look for spread. A PET scan uses a radioactive sugar tracer that collects in cells using a lot of energy, which is why it can pick up small deposits that other scans miss.
Staging is not one test. It is the assembled picture. Our page on breast cancer stages walks through how the categories are set.
Why it is still breast cancer
Cancer found in the liver after starting in the breast is metastatic breast cancer, not liver cancer.
NCI is explicit about this. Metastatic cancer keeps the name of the primary cancer, because under a microscope the cells are still breast cells and they respond to breast cancer treatments. Calling it liver cancer would point treatment in entirely the wrong direction.
What "triple positive" means
Thurston said she is "triple positive." This is a real and specific description, and it changes the treatment plan.
Breast cancer cells are tested for three receptors:
- Estrogen receptor (ER) — the cell uses estrogen to grow.
- Progesterone receptor (PR) — the cell uses progesterone.
- HER2 — a protein that drives growth when there is too much of it.
Triple positive means all three are present. Each one is a target. Hormone-blocking drugs address ER and PR. A separate group of antibody and antibody-drug conjugate treatments targets HER2 specifically.
This is the opposite of triple negative breast cancer, where none of the three is present and those targeted options are unavailable. Our page on breast cancer types explains the testing.
What stage 4 does and does not describe
Stage 4 says where the cancer is. It does not, on its own, say what happens next.
Treatment usually shifts from trying to remove the cancer to controlling it: slowing growth, easing symptoms, protecting organ function, and keeping life as full as possible for as long as possible. Depending on the situation, that can involve hormone therapy, HER2-targeted therapy, chemotherapy, immunotherapy, radiation, surgery, or procedures aimed at symptoms.
SEER records five-year relative survival of 33.8% for female breast cancer that has spread to distant sites. That figure needs three caveats and deserves all of them. It pools every subtype together, including those with far fewer treatment options. It covers diagnoses from 2016 to 2022, so it trails the drugs available now. And it is an average across a large population, which means it describes a group and cannot describe an individual.
Fertility, and the order things happen in
Thurston said she delayed the start of treatment to focus on fertility, and that her February planning included appointments for fertility alongside biopsy, surgery, and mental health.
This is worth flagging because the timing is largely one-way. Chemotherapy and hormone-blocking treatment can affect fertility, and options for preserving it are widest before treatment starts. It is a conversation for the first week, not the sixth month. Our guide on what to ask after a metastatic diagnosis covers questions that are easier to ask early.
Signs worth checking, whatever your age
Thurston's own advice on Good Morning America was to know your own breasts and to raise anything that seems off. The USPSTF recommends screening mammograms every two years starting at 40, which means most people under 40 are relying on noticing.
Book an appointment for:
- A new lump or firm area in the breast or armpit that does not change with your cycle.
- Skin dimpling, puckering, or a texture like orange peel.
- A nipple newly turning inward, or crusting and scaling that will not heal.
- Discharge from one nipple without squeezing, particularly if bloody.
- One breast becoming red, warm, or swollen over days or weeks.
- Any one-sided change that has lasted more than two to three weeks.
Being under 40 is not a reason to wait, and it is not a reason for a clinician to dismiss a finding.
What this story cannot tell you
- We report her disclosures on their dates. Nothing here describes her current health, and a scan result from October 2025 says nothing about any later one.
- One person's response to treatment predicts nothing about another's, even with the same receptor status.
- A new ache or an odd blood test does not establish that cancer has spread. Symptoms of metastasis overlap heavily with ordinary causes.
- Screening and prevention lower risk and catch some cancers earlier. They do not prevent every metastatic diagnosis, and nobody should be blamed for one.
- Nothing here is medical advice.
Sources
- ABC News, "Former 'Bachelorette' star Katie Thurston reveals breast cancer diagnosis," February 17, 2025: https://abcnews.go.com/GMA/Culture/former-bachelorette-star-katie-thurston-reveals-breast-cancer/story?id=118898831
- NBC News / TODAY, "Katie Thurston confirms her breast cancer is Stage 4," March 29, 2025: https://www.nbcnews.com/pop-culture/celebrity/katie-thurston-confirms-breast-cancer-stage-4-rcna198744
- ABC News, "'Bachelorette' alum Katie Thurston shares update on breast cancer diagnosis," October 16, 2025: https://abcnews.go.com/GMA/Culture/bachelorette-alum-katie-thurston-shares-update-breast-cancer/story?id=126553914
- National Cancer Institute, Metastatic Cancer: When Cancer Spreads: https://www.cancer.gov/types/metastatic-cancer
- SEER Cancer Stat Facts, Female Breast Cancer: https://seer.cancer.gov/statfacts/html/breast.html
- U.S. Preventive Services Task Force, Breast Cancer: Screening: https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/breast-cancer-screening
How this page was made
An AI-assisted editorial system helped prepare this page. No named medical reviewer has reviewed it unless one is listed.
The National Cancer Information Foundation publishes Cancer Explained. It is not a diagnostic service, does not recommend treatments, and is not for emergencies.
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Put the story in context
Prevention, possible warning signs, screening, and diagnosis
This story relates to Metastatic breast cancer. The information below is general: it does not reveal anything else about a public person’s health, and not every point applies to every cancer. Personal advice depends on age, symptoms, family history, exposures, and medical history.
Prevention and risk reduction
Not every cancer can be prevented. Avoiding tobacco, protecting skin from ultraviolet radiation, limiting alcohol, staying active, and receiving recommended HPV or hepatitis B vaccination can lower the risk of certain cancers. A risk factor is not a prediction or a cause in one individual.
Symptoms and possible early signs
Possible signs vary and are often caused by conditions other than cancer. Changes worth discussing include a new lump, unexplained bleeding or weight loss, a persistent cough, lasting bowel or bladder changes, a changing skin spot, or symptoms that persist or worsen. Some early cancers cause no symptoms.
Screening and early detection
Screening looks for certain cancers before symptoms begin. Recommended tests exist only for some cancers and depend on age and risk. Screening can have benefits and harms; it is not the same as evaluating a new symptom, and there is no single routine scan or blood test that reliably screens for every cancer.
How cancer is diagnosed
Diagnosis may involve a history and exam, imaging, laboratory tests, and often a biopsy. Pathology can identify the cancer type and may test biomarkers that guide treatment. Symptoms, screening results, tumor markers, or online stories alone cannot confirm cancer.
Learn about this story’s cancer topic
A public story may encourage questions, but it should not be used to estimate your risk or choose testing. Contact a healthcare professional about a persistent or concerning change. Seek urgent care for severe or rapidly worsening symptoms.