Ductal Carcinoma In Situ (DCIS): What It Is and Why It Matters
The Ductal carcinoma in situ (DCIS – Ductal Carcinoma In Situ) is one very early form of cancer, which remains confined within the milk ducts, without having invaded the surrounding tissues or metastasized. Although it bears the term "carcinoma", it is non-invasive cancer and has an excellent prognosis with appropriate treatment.
Biologically, DCIS differs from invasive ductal carcinoma and not the same as lobular carcinoma in situ (LCIS), which is not considered a true cancer but an indicator of increased risk for future malignancy.
Why Are DCIS Diagnoses Increasing?
The rapid increase in DCIS diagnoses in recent decades is associated with the widespread implementation of preventive mammography.
- In the 1970s, the incidence was about 6 cases per 100,000 women.
- In 2004 it reached 33 per 100,000, and since then it has been following a stable or increasing course.
- In 2024, estimated to have been diagnosed 56,500 new cases of DCIS in the USA.
- For 2025, approximately 59,080 new diagnoses are expected, accounting for around 19% of all breast cancer cases.
- In certain age groups (50–64 years), incidence reaches 88 per 100,000 women.
The main goal of treatment is to prevent progression of DCIS to invasive cancer.
What Are the Risk Factors?
The Risk factors for DCIS are similar to those for invasive breast cancer and include:
- Age (risk increases with age)
- Family history of breast cancer
- High breast density
- Obesity
- First childbirth after age 30
- Carriers of BRCA1 or BRCA2 mutations
How is it diagnosed?
Up to 90% of DCIS cases are diagnosed incidentally, through screening mammography, without the presence of symptoms. In 90% of cases, the finding is suspected microcalcifications, often confluent or irregularly shaped.
The stereotactic core needle biopsy It is the most widespread and accurate diagnostic method. It is performed under local anesthesia and is based on mammographic coordinates.
In special cases (e.g., lesions near skin or implants, obesity, small breasts), surgical biopsy guided by wire localizationunder general anesthesia is performed.
What Is the Treatment for DCIS?
Treatment aims to remove the lesion and prevent recurrence.
- The most common method is the lumpectomy (breast conservation), usually with the guidance of a guide wire. It is often followed by postoperative radiotherapy.
- In extensive or multifocal disease, it is applied total mastectomy.
- Sentinel lymph node biopsy not required in most cases of DCIS unless high-risk features are present.
If the damage is hormone-dependent (positive hormone receptors), adjuvant hormone therapy may be recommended (e.g. tamoxifen or aromatase inhibitor), to reduce the risk of recurrence or the appearance of new damage in the other breast, after an individual discussion with the treating physician.
Conclusion
Ductal carcinoma in situ (DCIS) is a very early form of breast cancer with an excellent cure rate. Prevention through screening mammography, accurate diagnosis, and targeted treatment are crucial steps to protect women's health.
References
- American Cancer Society. Breast Cancer Facts & Figures 2024-2025.
- Breastcancer.org. U.S. Breast Cancer Statistics, 2025.
- Wang SY et al. Long-Term Outcomes of DCIS: A Meta-Analysis. JAMA Oncol. 2015;1(7):888–896.
- Elshof LE et al. Ten-year follow-up of DCIS patients. Ann Surg Oncol. 2015;22(12):3848–3855.
- NCCN Clinical Practice Guidelines in Oncology: Breast Cancer (DCIS section), Version 4.2025.
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