Research Purpose: 
To compare the clinical efficacy of conventional targeting methods vs. customized 3D printing surgical guide for breast-conserving surgery after neoadjuvant chemotherapy, which is made patient specific based on MRI. 

Research Background: 
If the tumor size is large in breast cancer patients, the possibility of conserving the breasts by reducing the size of breast cancer by performing the neoadjuvant chemotherapy is increasing. It is important to know the exact area of residual cancer for complete resection of the tumor during partial resection after neoadjuvant systemic therapy. Accurate area marking was difficult. Usually, the tumor is marked by ultrasound or mammography guide H-wire insertion to confirm the location of the tumor before surgery, but there are several limitations.

1) Neoadjuvant systemic therapy (NST) 
Neoadjuvant systemic therapy in breast patients has the advantage of being able to see the effect of treatment in advance, and it is possible to reduce the size of the tumor so that it can be operated in patients who cannot operate or switch from total mastectomy to partial resection. 

2) Breast MRI 
MRI is the most accurate imaging method for predicting areas of breast cancer. In particular, it has good accuracy in predicting the area of residual cancer after NST. However, conventional targeting methods make it difficult to quantitatively mark the area of the tumor observed in MRI.
Problem 
* MRI posture differs from surgical posture
-For accurate diagnosis, breast MRI is performed in the prone position using a breast coil. 
-Since surgery is performed in supine position, compared with the lesion location determined by prone MRI, there is a constant deviation due to breast deformation, which makes it difficult to accurately determine the location of the lesion during surgery.

3) Breast Conserving Surgery (BCS) 
The positive resection margin should lead to recurrence, so that the area of the tumor should be accurately identified before surgery to remove it precisely so that there is no tumor at the margin. Completely remove the tumor but preserve normal tissue as much as possible for cosmetic results. 

Problems with conventional targeting methods
-Difficulty in marking the area of the tumor on the MRI in the breast
Cannot quantitatively mark tumor areas
-It is difficult to know the original tumor area before treatment
-Causing pain in patients
-The procedure takes time
-Deviation occurs according to the operator

In order to solve these problems, we have developed a patient customized 3D printing breast surgery guide (3DP-BSG) that can display the tumor range using MRI information before and after treatment. we wants to check the accuracy and usefulness of 3DP-BSG in BCS after NST.

Treatment

The experimental group applies the 3D printing breast surgery guide (3DP-BSG). 3DP-BSG is prepared based on pre- and post-treatment medical images (MRI / CT) in patients undergoing neoadjuvant chemotherapy. In breast-conserving surgery, 3DP-BSG is used to target tumors.

Arm Label

Target Number of Participant

Arm Type

Arm Description

* Control group: Standard treatment of surgical method using the conventional targeting method
①  To mark the area of the tumor before surgery, mammography or ultrasound guide hook wire and skin marking are performed according to the determination of the concentration.
②  After removing the tumor along the marked area, check several surrounding margins for remaining tumors through frozen section analysis to determining further resection.
③  After the hemostasis, check that there is no bleeding and complete the surgery.
Adverse events are recorded when there are new signs/symptoms or deterioration of underlying diseases after random assignment.
The investigator satisfaction survey is completed

Arm Label

Target Number of Participant

Arm Type

Arm Description

Test group: Apply 3D printing breast surgery guide (3DP-BSG)
① Surgical guide is produced by 3D printing to target the tumor by 3D modeling breast and tumor using neoadjuvant before and after medical images (MRI, CT)
Place the 3DP-BSG on the breast surface using the body landmarks (top end point of the sternum and the corresponding side / opposite papilla) before surgery
③ Mark the area of the tumor on the surface of the breast using 3DP-BSG and inject the blue-dye using a syringe along the guide column to indicate the extent of resection around the tumor.
④ After removing the tumor along the markings on the skin outside / inside the breast, check the presence of residual cancer through the cryosection test in several areas of the marginal resection to determine whether to further resection.
⑤ After the hemostasis check that there is no bleeding and finish the operation.

Gender

Age

Description

•Female patients from 20 to 79  years of age 
•Patients who received or is receiving neoadjuvant chemotherapy, after diagnosed with invasive breast cancer by histology
•Patients who are scheduled to have breast-conserving surgery after neoadjuvant chemotherapy 
•Subjects who fully understands and agrees in writing to the Informed consent form

• Patients who have contraindications of MRI
 ① Those with an inserted electrical device, clip for the prevention of aneurysm, artificial of metallic material around the eyeball
 ② Patients who have Claustrophobia
 ③ Patients with difficulty using gadolinium-based angiography - severe allergic or impaired of kidney function (creatinine > 2.0) 
 ④ Pregnant
• Difficult partial resection due to large calcification lesions
• Patients deemed unsuitable to participate in this clinical trial at the Investigator's discretion

Tumor at first resection margin

During surgery

Distance from tumor to edge of specimen

Postoperative pathology examination

Volume of the removed specimen

Postoperative pathology examination

Weight of removed specimen

Postoperative pathology examination

Surgery time

During surgery

Patient satisfaction

Outpatient visit after surgery (2 weeks after surgery +/- 7 days)

Surgeon's Satisfaction

Within 7 days after surgery