In the case of a patient undergoing total mastectomy for intraductal carcinoma (DCIS), the sentinel lymph node is not excised during the primary surgery but only marked for identification. If the final histological examination confirms invasive cancer, delayed surgery is performed to remove the sentinel lymph node that was marked during the initial surgery.

primary endpoint : The success rate of identifying the sentinel lymph node that was marked during the primary surgery in cases where the final histological examination confirms invasive cancer is evaluated.

addendum) The previously documented Breast-Conserving Surgery has been corrected to reflect the accurate procedure of Total Mastectomy.

Primary surgery:

Patients diagnosed with intraductal carcinoma through histological examination and scheduled for axillary lymph node dissection are included.

Prior to the surgery, blue dye and/or radioisotope injection are used to identify the sentinel lymph node, similar to the current practice.

total mastectomy surgery is performed. After identifying the sentinel lymph node in the axillary region, its location is marked using a titanium clip (size 2-4mm) or sutures (Maxon 3-0, a slow monofilament absorbable suture).

The number of marked sentinel lymph nodes is recorded for documentation.

Confirmation of pathological examination results:

If the final surgical specimen confirms invasive carcinoma (size > 1mm) through pathological examination, sentinel lymph node surgery is performed.

addendum)

1. Suture Specification The surgical procedure will utilize Maxon 3-0, a slow monofilament absorbable suture for optimal tissue approximation and healing.
2. Management of Microinvasive Cancer For cases where the tumor size is 1 mm or smaller (microinvasive cancer), the decision to proceed with reoperation will be made at the discretion of the treating physician based on clinical judgment.

Secondary surgery:

Prior to the surgery, an axillary view x-ray is taken to verify the location and number of the clips.

Blue dye and/or radioisotope injection is administered near the axillary incision site.

Accessing the axillary region involves identifying the marked areas using clips or sutures and detecting sentinel lymph nodes for biopsy.

The number of removed clips/sutures and the number of sentinel lymph nodes identified are documented for record keeping.

addendum) Axillary X-ray and Sentinel Node Mapping Axillary x-ray and the use of blue dye or radioisotope injection for sentinel lymph node mapping are not mandatory and may be utilized at the physician's discretion.

Inclusion Criteria:

• Patients aged 20 to 75 years old.
• Patients diagnosed with DCIS through histological examination.
• Patients undergoing mastectomy

Exclusion Criteria:

• In cases where the histopathological findings of the tissue examination indicate suspicious invasive lesions.
• In cases where imaging tests or physical examinations suggest possible lymph node metastasis.
• In patients who have previously undergone axillary lymph node surgery on the same side as the current procedure.
• Pregnant patients.