What is DCIS? How is stage 0 breast cancer treated?
- ป้าหมอนุช
- 10 hours ago
- 8 min read
DCIS (Ductal Carcinoma In Situ) is stage 0 breast cancer confined to the milk ducts and has not spread to surrounding tissues — considered the earliest stage with a very high cure rate. The primary treatment is lumpectomy (breast-conserving surgery) followed by radiation therapy. Numarak Hospital has a key advantage in its Specimen Radiography (in-operative X-ray machine), which significantly reduces the re-excision rate, and also offers IORT (Intrabeam) as an option for eligible DCIS patients.
What is DCIS?
DCIS stands for Ductal Carcinoma In Situ — a condition where abnormal cells develop within the milk duct but have not yet broken through the duct wall into the surrounding tissues. In medical terms, this is called "stage 0" or Non-invasive Breast Cancer.
The term "in situ" in Latin means "stationary," referring to the fact that the cancer cells are confined to their original location and have not invaded the surrounding breast tissue or lymph nodes. This results in a very high cure rate for DCIS — an overall survival rate close to 100% when treated appropriately.
Why DCIS is important:
DCIS accounts for ~20-25% of all breast cancers detected in the era of widespread mammogram screening.
If left untreated, approximately 30-50% of DCIS will develop into invasive cancer within 10-20 years.
DCIS treated at this stage has a high chance of complete recovery.
Mammogram screening is key to detecting DCIS because most cases are asymptomatic.
How does DCIS differ from invasive breast cancer?
Location of cancer cells: DCIS is located in the milk duct. This invasive cancer has penetrated the duct wall and spread to surrounding tissues.
Spread: DCIS cannot metastasize. Invasive cancer can spread to lymph nodes and other organs.
Staging: DCIS = Stage 0; Invasive Cancer = Stages I-IV, based on size and distribution.
Cure rate: DCIS is close to 100%. Invasiveness depends on the stage.
Treatment: DCIS usually does not require chemotherapy. Invasive treatments may require chemotherapy, immunotherapy, or targeted therapy.
Detection and symptoms of DCIS.
Most DCIS patients (over 80%) are asymptomatic — detected via mammogram screening which shows microcalcifications (small calcified spots), a hallmark of DCIS.
Possible symptoms (in a rare case):
Nipple discharge (also known as lymphatic fluid or blood)
A palpable mass — found in cases of mass-forming DCIS.
Paget's Disease, a rash on the nipples, is a variant of DCIS.
In most cases, there are no symptoms at all; it is detected via mammogram.
Diagnostic testing:
Mammogram (3D Tomosynthesis): Detects microcalcifications — Hologic 3D + Genius AI enhances accuracy.
Ultrasound: Used in conjunction with ultrasound — DCIS is not often clearly visible on ultrasound because it is usually microcalcifications.
MRI: Used to assess the extent of DCIS, especially if Extensive Intraductal Component (EIC) is suspected.
Core Needle Biopsy: A tissue sample is taken with a small needle for confirmation — often performed under stereotactic or vacuum-assisted biopsy.
DCIS Grades — Low, Intermediate, High
Pathologists classify DCIS into 3 grades based on cellular characteristics, which is crucial for treatment planning.
Low Grade (Grade 1): Cells are near normal, grow/divide slowly, and have a low risk of becoming invasive.
Intermediate Grade (Grade 2): Moderately abnormal cells.
High Grade (Grade 3): Highly abnormal cells, rapid growth/division, often with comedo necrosis (cell death in the middle of the duct), higher risk of invasive progression.
Comedo necrosis is a pathological feature indicating increased aggression of DCIS. It is often found in high-grade DCIS and is a factor that leads physicians to consider a comprehensive treatment plan (lumpectomy + radiation) rather than simply observing symptoms.
Treatment of DCIS
Treatment options vary depending on the size, grade, and location of the DCIS, as well as the patient's characteristics.
5.1 Lumpectomy + Whole Breast Radiation Therapy (Standard)
The primary treatment for DCIS is a lumpectomy (breast-conserving surgery) followed by 3-6 weeks of whole-breast radiation therapy — reducing the risk of recurrence in the same breast by half.
5.2 Lumpectomy without radiation therapy (Selected Low-Risk Cases)
In low-risk DCIS (low grade, small size < 2.5 cm, margin ≥ 3 mm, age > 50 years), lumpectomy alone without radiation therapy may be considered — especially if the oncotype DX DCIS score is low.
5.3 Mastectomy (Selected Cases)
For cases of large or multicentric/extensive DCIS, nipple-sparing mastectomy + immediate reconstruction is a good option to preserve breast appearance.
5.4 IORT (Intrabeam) for DCIS — in eligible cases.
At Namarak Hospital, some DCIS patients can receive IORT (In-Surgical Radiation Therapy) instead of conventional radiation therapy for 3-6 weeks, following the TARGIT-A protocol. The appropriate criteria are:
Age ≥ 50 years (some institutions use 45 years)
Low to Intermediate Grade DCIS
Size ≤ 2.5 cm.
Single focus (not multicentric)
No margin ≥ 2 mm.
ER-positive (HR+)
No extensive intraductal component or lymphovascular invasion.
The medical team will assess each individual's suitability. If they meet the criteria, the patient can complete radiation therapy in a single day in the operating room — without needing to come for daily radiation therapy for 3-6 weeks.
5.5 Endocrine Therapy (for HR+ DCIS)
In patients with DCIS who are estrogen receptor positive (ER+), tamoxifen or aromatase inhibitors may be considered for 5 years to reduce the risk of recurrence and the development of cancer in the other breast.
Why is the re-excision rate so low at Namarak Hospital? — Intraoperative Specimen Radiography
A classic problem with DCIS surgery is the high re-excision rate in general hospitals — because DCIS is mostly detected as microcalcifications on mammograms that are not palpable. This means that during surgery, surgeons have to guess the extent of the lesion, resulting in incomplete excision or margins that are too close, requiring the patient to return for a repeat surgery after pathology results are obtained.
The international DCIS re-excision rate:
General hospitals: 25-35%
Breast care center (standard): 15-20%
Specialized centers with Specimen Radiography in OR: 8-12%
How does Specimen Radiography work?
At Numarak Hospital, we have an Intraoperative Specimen Radiography (IS) machine in our operating room — as soon as the surgeon takes a DCIS biopsy, we take an X-ray of that piece on the operating table to check three key points:
1. Were the targeted microcalcifications achieved? — Compared to the pre-operative mammogram.
2. How far are the microcalcifications from the edge of the tissue sample? — Check if the margin is free.
3. Are there any remaining suspicious calcifications that might need to be removed?
If the biopsy X-ray reveals a margin that is too close or if residual calcifications remain , the surgeon can immediately remove additional tissue in the same operating room — while the patient remains under anesthesia — eliminating the need for a follow-up surgery on a different day.
Benefits that patients will receive.
Reduce the re-excision rate — from 25-35% to 8-12%.
Reduce stress and anxiety — get immediate margin results in the operating room, no need to wait 7-14 days for pathology.
Reduce costs and time — no need for repeat surgery, no need for a second round of anesthesia.
Better cosmetic results — one incision, no need for repeated treatments.
No delays in ongoing treatment — start radiation/hormone therapy on schedule.
Increase confidence in cancer treatment outcomes — margin is safe from the start, avoiding the risk of local recurrence.
Research from Layfield et al. (Br J Surg 2012) and McCormick et al. (Ann Surg Oncol 2004) confirms that the use of Intraoperative Specimen Radiography significantly reduces the re-excision rate in DCIS and early breast cancer surgery.
This technique works in conjunction with Scout Radar Localization , which identifies undetectable DCIS locations — the combination of these two technologies results in exceptionally high accuracy for DCIS surgery at Namarak Hospital.
Monitoring and Recurrence Risk After DCIS Treatment
Patients with DCIS should be closely monitored after treatment to check for recurrence or the development of new cancer.
Years 1-5: Physical examination and mammogram every 6-12 months.
Year 5 onwards: Mammogram once a year.
Risk of recurrence (Lumpectomy + Radiation): ~10-15% in 10 years.
Half of the recurrences are DCIS again, and the other half become invasive cancer.
Risk of developing new cancer in the other breast: ~5-10% in 10 years.
Why choose Namarak for DCIS treatment?
Intraoperative Specimen Radiography in the operating room — Significantly reduces the re-excision rate.
Hologic 3D Mammogram + Genius AI — Accurately detects microcalcifications in the early stages.
Scout Radar Localization — Accurately locates undetectable DCIS (Diagnostic Intervention System) objects to the millimeter level.
IORT (Intrabeam 600) — An alternative to DCIS in eligible cases.
A team of five specialized breast surgeons — a multidisciplinary approach.
Medical oncologist — for planning endocrine therapy.
Hidden Scar + Oncoplastic Surgery — for better cosmetic results.
The philosophy of "like visiting a friend's house" — High Tech, High Touch
Frequently Asked Questions (FAQ)
Is DCIS really cancerous?
DCIS is stage 0 breast cancer — it is a pathological cancer that has not spread outside the milk ducts and therefore cannot metastasize to other organs. At this stage, it is considered "pre-invasive" or "non-invasive." Appropriate treatment can lead to a cure in almost all cases.
Can DCIS spread?
DCIS itself is not yet invasive (in situ), but if left untreated, approximately 30-50% of DCIS will develop into invasive cancer within 10-20 years, depending on the grade of DCIS — high-grade DCIS has a higher risk than low-grade DCIS. Therefore, doctors recommend treatment for all cases.
Will a repeat surgery be needed for DCIS?
Depending on whether the initial surgery was successful and the margins are safe, the re-excision rate for DCIS at general hospitals is 25-35%. This is because DCIS is often detected by microcalcifications that are not palpable. At Namarak Hospital, we use Intraoperative Specimen Radiography to examine the tissue sample immediately in the operating room — if the margins are too close, additional tissue can be removed on the same day. This results in a very low re-excision rate.
Does DCIS require chemotherapy?
Typically, chemotherapy is not necessary — DCIS is stage 0 cancer that has not spread, so chemotherapy is not required. The primary treatment is surgery, radiation therapy, and in ER-positive cases, hormone therapy (Tamoxifen or Aromatase Inhibitor) may be used.
Can DCIS use IORT (Intrabeam) instead of conventional radiation therapy?
In some cases, IORT for DCIS is suitable for patients aged ≥ 50 years, low to intermediate grade, size ≤ 2.5 cm, single focus, margin ≥ 2 mm, and ER-positive. Our medical team will assess suitability on an individual basis according to the TARGIT-A protocol.
Can DCIS recur?
Yes — the risk of recurrence in the same breast after lumpectomy + radiation is ~10-15% in 10 years. Half recur as DCIS, and half become invasive cancer. Regular mammograms are therefore very important.
Are there gene tests for DCIS to help with decision-making?
There is an Oncotype DX DCIS Score, a genetic test that examines 12 genes from a DCIS tissue sample to assess the risk of recurrence at 10 years. It is used to determine whether a patient needs radiation therapy after lumpectomy — suitable for patients who need insightful information for decision-making.
Why is DCIS detected so early?
Because DCIS is often detected during mammogram screening, where microcalcifications—small calcified deposits in the breast that are undetectable and asymptomatic—regular mammograms as recommended (every 1-2 years for women over 40) are key to detecting DCIS at an early stage where it can be easily treated and cured. The Hologic 3D Mammogram + Genius AI machine at Namarak detects microcalcifications with greater accuracy than a standard 2D mammogram.
About Numarak Hospital
Numarak Hospital is a specialized breast and breast cancer hospital located on Phetchaburi Road, Bangkok. Operating under the philosophy of "Like visiting a friend's house" — High Tech, High Touch — it combines international-standard technology with compassionate care.
For consultations regarding DCIS or to request a second opinion, please contact:
Note: This information is for general knowledge purposes only and is not personalized medical advice. Appropriate treatment guidelines depend on the nature of the disease and the individual's physical condition. Please consult a specialist physician for proper diagnosis and treatment.
References
NCCN Clinical Practice Guidelines — Breast Cancer (Version 2.2025) — DCIS Section
Vaidya JS, et al. TARGIT-A Trial — IORT for Early Breast Cancer including DCIS. BMJ 2020;370:m2836
Layfield DM, et al. Intraoperative Specimen Radiography. Br J Surg 2012
McCormick JT, et al. Intraoperative Specimen Radiography reduces Re-excision Rate. Ann Surg Oncol 2004
Solin LJ, et al. Oncotype DX DCIS Score — Genomic Test for DCIS Recurrence Risk
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