Biopsy and pathology
What Does Carcinoma in Situ Mean?
Carcinoma in situ · say it: kar-sih-NOH-muh in SY-tooAlso written: CIS, stage 0, DCIS (ductal carcinoma in situ), non-invasive carcinoma
Short answer
Carcinoma in situ means abnormal cells that look like cancer are found, but they have not grown beyond the layer where they started.
What it means
"In situ" is Latin for "in its original place". Carcinoma in situ means cancer-like cells are present, but they are still contained within the lining layer where they began and have not invaded deeper tissue.
It is sometimes called stage 0. A common example is ductal carcinoma in situ (DCIS) in the breast, where the cells are still inside the milk ducts.
Because it has not invaded, it cannot spread in its current form. It is often treated to stop it from becoming invasive cancer, and options vary by type and organ.
Where you may see it
- Biopsy and surgical pathology reports
- Breast pathology reports (DCIS)
- Bladder, skin and cervical pathology reports
📄 How it looks on a report
Ductal carcinoma in situ, intermediate nuclear grade. No invasive carcinoma identified.
🙅 What it does not mean
- It is not the same as invasive cancer. The cells have not grown beyond their starting layer.
- It does not mean nothing needs to be done. Treatment is often recommended.
- "Stage 0" does not mean no disease. It means the earliest, non-invasive form.
🎯 Check yourself
Which of these is the right meaning of “Carcinoma in situ”?
🗒️ Questions to ask your doctor
🧾 Reports where you will see “Carcinoma in situ”
Paste or upload the report and every line of it is explained, with personal details removed first.
🔗 Read more from trusted sources
- “Carcinoma in situ” on MedlinePlus ↗
US National Library of Medicine
- NCI Dictionary definition ↗
US National Cancer Institute: “carcinoma in situ”
Seeing this word on your own report? Get every line of it explained, free.
Explain my report🧩 Related words
🔎 Look up another word
More words: biopsy and pathology
General information about a medical word, not advice about your own results. Ask the clinician who ordered the test what it means for you.