Abstract
OBJECTIVE:
To retrospectively explore correlation of the resected specimen volume of breast microcalcification lesions and endogenous and exogenous factors of stereotactic needle localization biopsy (SNLB).
MATERIALS AND METHODS:
Totally 214 patients underwent SNLB for non-palpable breast lesion with microcalcification lesions. Of 211 patients, 198 patients underwent single needle localization and 13 patients underwent multi-needle localization (26 lesions). Lesion sizes, distribution characteristics, lesion localization accuracy and resected specimen volumes were recorded and analyzed using a generalized linear model (GLM).
RESULTS:
The average lesion diameter is 2.63±1.73 cm. The localization accuracy of 187 lesions were moderate, 26 were too deep and 11 were too superficial. The mean resected specimen volume (V) was 17.51±5.14 cm3. One-way ANOVA analysis showed that 3 factors, including lesion sizes, distribution characteristics and the localization accuracy were associated with resected specimen volume (F = 67.56–112.78, P < 0.001). GLM revealed that lesion sizes, single clustered distribution and accurate localization were significant factors for resected specimen volume (F = –4.82–11.36, P < 0.05). The ratio (%) of the resected specimen volume to the involved breast volume (V0) was defined as the degree of breast defect. The mean breast defect of 125 benign patients (V/V0) was 27.5% ranging from 10.1% to 42.3%.
CONCLUSION:
Average lesion diameter and localization accuracy are highly significant variables for the resected specimen volume. Localization accuracy as a subjective controllable variable is one of the important factors that determine the volume of lesion resection. Single clustered distribution was more susceptible localization accuracy than other characteristic distributions. Improving localization accuracy can reduce resected specimen volume, which can reduce breast defect to a certain extent.
Keywords
Introduction
With the spread of breast cancer screening population every year and the extensive use of high resolution X-ray digital mammography and other imaging screening modalities [1, 2], a large number of non-palpable breast lesions (NPLBs) is found in clinical, of which microcalcifications are the main feature in early stage of breast diseases, especially breast cancer [3–6]. For NPLBs of Breast Imaging Reporting and Data System (BI-RADS) category 4 and above, lesion biopsy and further surgical resection are recommended. Core needle biopsy (CNB), vacuum-assisted biopsy (VAB) and needle localization biopsy (NLB) are the main lesion biopsy for histological confirmation methods [7–9], of which stereotactic needle localization biopsy (SNLB) can cover the shortage of histological underestimation due to insufficient specimen of stereotactic core needle biopsy (SCNB), and avoid the possible needle metastases of breast cancer cells during stereotactic vacuum-assisted biopsy (SVAB) [10–12].
SNLB can maintain the morphological integrity as far as possible by oriented resection and obtain enough reliable pathological specimen for qualitative diagnosis of NPLB at the same time. Previous researches [13, 14] showed that 52–60% of the SNLB histological diagnosis are benign. Of these patients, the biopsy resected specimen volume directly decides the breast defect degree after surgical biopsy, and affects the psychological health status and quality of life of females to a certain extent, especially for Asian young women because of insufficient glands and small volume. Meanwhile, most of the affected women who are under 40 years and still in the reproductive age with breastfeeding needs. It is important for them to maximize breast shape and function after SNLB.
The resected specimen volume achieved by SNLB directly determines the extent of breast defects. SNLB is performed under x-ray guidance. Patient position, the site and depth of needle insertion are dependent on microcalcification sizes
This study retrospectively analyzed the data of 211 patients with NPLBs who underwent SNLB biopsy in our hospital to find out the variables which are related with the resected specimen volume by analyzing variables of lesion size, distribution characteristic and localization accuracy.
Materials and methods
Study population
The data of 214 patients who were diagnosed with NPLBs and underwent stereotactic wire localization SNLBs biopsy from April 2015 to December 2017 in our hospital were enrolled. And three patients were excluded because of intraoperative vagus nerve response.
211 patients were female, age of 26 to 63 years old (Median, 39 years old). Mammography examination showed 224 lesions with single-clustered, mulit-sand-like, scattered or regional distributed microcalcifications, of which, 208 patients were BI-RADS category 4 to 5 and 3 patients were BI-RADS category 3 with severe anxiety. All patients underwent SNLB biopsy after mammography diagnosis in a week. This research was approved by medical ethics committee and all patients signed informed consent.
X-ray guided by stereotactic wire localization biopsy
We used MAMMO DS digital high resolution breast X-ray equipment of GE Company. Matched three-dimensional positioning system and fishhook-shaped single hook locating pin of 20G (hook90/80/70, Promex Company) was applied. Conventional and orientation photographing applied Stand mode exposure. Previewing conventional images before orientation to choose orientation calcification. Patients were asked to sit, soft rolls were put behind their back for support to reduce displacement. CC or ML, LM oppression were chosen, according to lesion size, position and distribution to put target calcification in the center of posting, taking the shortest distance of locating pin passing through breast. Oppressed breast and extended glands at the same time to reduce the skin surface apophysis after oppressing the breast. Pressure was 15–24dan till there was no breast morphological change. Applied each film of 0° and±15° photography for bulb tube, system automatically calculated the three-dimensional coordinate value. Chose locating pin of appropriate length, adjusted rack to preselection spot, sterilized skin surface, insert the needle through needle holder groove and made sure whether the ubiety between the needle tip and the target calcification is right or not, and then relieved oppression and pulled out epitheca. Took a film perpendicular to the needle inserting direction, verified whether the back stitch is open or not, evaluated the distance from needle tip to lesion and fixed the end of the guide wire. Delineated the excision extent on the last localization film to guide surgery.
GLM related parameters
Microcalcification distribution (
Statistical data analysis
SAS 9.5 software was used for recording data and statistical analysis. Quantitative data was represented as
Results
211 patients (224 lesions) with microcalcifications was studied, including 127 of single clustered, 53 of multiple clustered and 44 of regional distribution as
According to the pathological diagnosis (Table 1), 135 (60.3%, 135/224) lesions were benign, 27 microcalcifications were cystic hyperplasia, 26 lesions were hyperplasia with calcification, 32 lesions were hyperplasia accompanied with intraductal papilloma, 39 lesions were mammary adenosis, 7 lesions were cyst with latex calcification, 4 lesions were inflammation and 21 lesions (9.4%, 21/224) were atypical ductal hyperplasia (ADH). 68 lesions (30.4%, 68/224) were pathologically diagnosed as breast cancer, among which 37 lesions were invasive ductal carcinoma, 11 were lobular carcinoma, 8 lesions were mucinous adenocarcinoma and 12 lesions were carcinoma in situ or intraductal carcinoma (Fig. 1).
Comparison of breast mammography BI-RADS category with pathological results
Comparison of breast mammography BI-RADS category with pathological results
DCIS: ductal carcinoma in situ, IDC: invasive ductal carcinoma, LC: lobular carcinoma, MAC: mucinous adenocarcinoma.

Patient, female, 42 years old. Right breast of non-palpable breast lesions with microcalcifications (1.1×1.5 cm2) on the superior lateral quadrant, the needle was inserted vertically. Localization moderate. Histologic result was shown as intraductal carcinoma in situ with small focal ductal carcinoma infiltration.
Lesion average diameter (
One-way analysis of variance lesion average diameter (D), lesion distribution (D*) and localization accuracy (L) with resected specimen volume (V)
df: degree of freedom.
GLM coefficient test of lesion average diameter (D), lesion distribution (D*) and localization accuracy (L) with resected specimen volume (V)
df: degree of freedom.
The localization accuracy rate among lesion of different size are 16.5%, 83.5%, respectively (Table 4). Breast defect as
Frequency among localization accuracy (L) and lesion average diameter (D)
Mammography was of high sensitivity and specificity for detecting non-palpable breast lesions with microcalcifications and could evaluate the benign and malignant degree of microcalcifications by BI-RADS. SNLB supplied possibility for the localization biopsy and resection of microcalcifications, which were defined as BI-RADS category 4 or 5, even some category 3 with severe anxiety. Researches [13, 14] in the past about localization biopsy of microcalcification were restricted to comparison of calcification imaging manifestation and pathological results to elaborate the application value of SNLB, of which 55–60% of the patients were diagnosed as benign according to localization biopsy pathological results. The resected specimen volume during SNLB directly decided the breast defects post-surgery. As an important organ of female secondary sex characteristic, breast defect could lead to psychological burden to some extents and affect the love, marriage, family life of patients and caused fertility and lactation anxiety. The volume of resected specimen was depended on the objective factors of lesion sizes, distribution characteristic and localization accuracy and patient cooperation degree, which were extrinsic and can be controlled. Therefore, the improvement of localization accuracy during SNLB and patient cooperation degree might be effectively reduce the resected specimen volume and then decrease the breast defect degree to some extent.
The one-way analysis of variance of lesion sizes, distribution characteristic and localization accuracy with resected specimen volume turned out that their effects on the resected specimen volume are statistically significant difference (P < 0.05), which meant that all of them were independent variables affecting resected specimen volume. Generalized linear model (GLM) which had more extensive application range was chosen for fitting since the dependent variable of this research was continuous variables, while the independent variables were mixed variables. GLM is simple least squares regression, which can be used to analyze classified variable or discontinuous variable, instead of only continuous variables complying with normal distribution [18, 19]. This study analyzed the significance of each independent variable on dependent variable with GLM, to clear the magnitude of the influence on the resected specimen volume of objective variables and controllable variables, and then did likelihood-ratio test to the estimation coefficient of the significant variables of the equation. The estimation coefficient of lesion size (
The decrease of the resected specimen volume is about 3.23 times of the lesion of “single clustered” distribution comparing with the lesion of “multiple clustered” or “regional” distribution. Moreover, the lesion of “multiple clustered” distribution is 1.55 times smaller than the lesion of “regional” distribution, but the volume of the two sublayers is of no statistical difference. Location accuracy (
The analysis of localization accuracy among lesion of different size groups show statistical difference, which meant localization accuracy among lesion of different size was of different efficacy. The ratio was 16.5%, 83.5%, respectively. The localization accuracy of stereotactic wire localization biopsy for microcalcifications
The correlation analysis of lesion average diameter (
In addition, the breast defect (
Therefore, we should pay more attentions to the localization accuracy of stereotactic wire localization biopsy. We think that we should improve our skills according to the following five aspects: (1) Localization environmental requirement. Localization accuracy in terms of equipment depends on the accuracy condition of high precision electronic components, which may be affected by the environment temperature and humidity [23]. The standard conditions are room temperature 18°C∼26°C, humidity 20% ∼90%, and atmospheric pressure 860∼1060 hpa. (2) Adjustment of breast stereotactic instruments. Before localization, horizontal and vertical adjustment for equipment should be done (valid for 24 hours), make sure that every link of the localization system operates normally. The allowed error after adjustment should be less than 0.2 mm. (3) Patients position design [24]. Preview conventional radiography to know the lesion size, distribution and estimate the length of needle to be inserted. Design the shortest inserting path, inserting direction and the patient tolerable body position. (4) Choose the characteristic calcification as target. The target should be as close to the lesion center as possible [25]. (5) Psychological intervention to patients. Any movement of the patients during every step may lead to inaccurate localization. Good communication pre-operation to establish good trust, clear the importance of positive cooperation, dispersion of patients attention during operation to reduce the uncomfortable reaction are effective methods to ensure patients good cooperation [26].
Conclusion
SNLB is the most widely used and effective method for NLPBs with microcalcifications qualitative diagnosis and surgical resection. Meanwhile, more than half of the patients who accepted SNLB surgery are benign disease, it is of significant clinical value to retain breast integrity and improve the patient psychological health status after SLNB by improve the localization accuracy during SLNB to reduce breast defect to normal breast glandular tissue and breast resected extent, especially Asian women with small volume breast.
Disclosure
The authors report no conflicts of interest in this work.
Footnotes
Acknowledgments
This work was financially supported by the National Natural Science Foundation of China under Grant No. 81671757 and the CAMS Innovation Fund for Medical Sciences under No.2016-I2M-1-001 and Beijing Hope Run Special Fund of Cancer Foundation of China No. LC2016B07.
