Psychometric Properties of the Patient Health Questionnaire-9 in Patients With Breast Cancer.

OBJECTIVE: Due to the high frequency of depressive symptoms associated with breast cancer, it is crucial to screen for depression in breast cancer patients. While numerous screening tools are available for depression in this population, there is a need for a brief and convenient tool to enhance clinical use. This study aims to investigate the psychometric properties of the Patient Health Questionnaire-9 (PHQ-9) in patients with breast cancer. METHODS: Patients with breast cancer (n=327) who visited the Breast Cancer Clinic were included in this study. The reliability of the PHQ-9 was analyzed by Cronbach's α, and the construct validity of the PHQ-9 was explored by factor analysis. The concurrent validity of the PHQ-9 was evaluated by Pearson correlation analysis with the Hospital Anxiety and Depression Scale (HADS) and Perceived Stress Scale (PSS). RESULTS: The values of Cronbach's α ranged from 0.800 to 0.879 was acceptable. The exploratory factor analysis revealed that the one-factor model and two-factor model of the PHQ-9 explained 46% and 57% of the variance, respectively. The PHQ-9 were significantly correlated with those of HADS (r=0.702, p<0.001) and PSS (r=0.466, p<0.001). Consequently, the PHQ-9 demonstrated acceptable reliability and validity in breast cancer patients. CONCLUSION: The findings of this study indicate that the PHQ-9 exhibits acceptable reliability and validity in patients with breast cancer. The convenience of this brief self-report questionnaire suggests its potential as a reliable and valid tool for assessing depression in breast cancer clinics.

Management of Gestational Gigantomastia with Goldilocks Procedure after Mastectomy: A Case Report and Review of Literature.

Gestational gigantomastia is characterized by the rapid growth of breasts during pregnancy. The treatment method of gestational gigantomastia is unclear; if the medical treatment is ineffective, surgery is considered. However, sufficient research on which method is best to perform breast reconstruction for the gestational gigantomastia patient has not yet been conducted. Our patient was young and had aesthetic needs; thus, we did not recommend modified radical mastectomy. However, it was difficult for the patient to consider active reconstruction using an implant or autologous tissue because of the expected complications and economic problems. The patient had a thin body shape and very large breasts compared with the trunk. Therefore, breast volume was not significantly required after reconstruction. Additionally, we expected that a considerable portion of skin would remain after mastectomy as a tubular-shaped breast. It was expected that the Goldilocks technique would be sufficient to meet the patient's volume needs. Therefore, we proceeded with total mastectomy and reconstruction using the Goldilocks procedure. No complications were recorded after the operation; most of the patient's discomfort was resolved, and the shape and size of the breasts were satisfactory.

Analysis of Watson for oncology and clinicians' treatment recommendations for patients with breast cancer in Korea: A single center experience.

Background: Various clinical applications have been attempted using artificial intelligence (AI) clinical decision support system (CDSS), and it has become a starting point for personalized cancer treatment. We aimed to identify the degree of agreement between the AI-CDSS, Watson for Oncology (WFO), and the clinician in treatment recommendations for Korean breast cancer patients and to provide guidelines for future improvement. Methods: One hundred and eighty-three breast cancer patients who underwent treatment at the Pusan National University Hospital between January 1, 2016 and May 31, 2017 were enrolled in this study. The concordance between WFO's and clinicians' treatment recommendations were examined according to various factors. Results: WFO gave the same treatment option recommendations as clinicians in 74 (40.4%) of the cases. According to the logistic regression, the difference in recommendation concordance between stage I and stage III was statistically significant (P = 0.004), and there was no difference among other factors. Conclusion: The concordance of treatment recommendations was low overall. However, this is largely attributable to the differences of medical insurance system and healthcare environment between the United States and Korea. In the future, region-specific features should be considered or reflected during the development of AI-CDSS.

Psychometric Properties of Assessment Tools for Depression, Anxiety, Distress, and Psychological Problems in Breast Cancer Patients: A Systematic Review.

OBJECTIVE: Various and accurate psychiatric assessments in patients with breast cancer who frequently suffer from psychological problems due to long-term survivors are warranted. This systematic review aimed to investigate the current evidence on psychometric properties of psychiatric assessment for evaluating psychological problems in breast cancer patients. METHODS: This systematic review progressed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline. Four electronic databases such as Web of Science, PubMed, Embase, and Cumulative Index to Nursing and Allied Health Literature were searched. This study protocol was registered on Open Science Framework. RESULTS: Of the 2,040 articles, 21 papers were finally included. Among them, only five studies showed the performance of psychiatric assessment tools. Among 13 assessment tools used in the selected articles, the Hospital Anxiety and Depression Scale (HADS), Distress Thermometer (DT), or Mini-Mental Adjustment to Cancer Scale was frequently used for the evaluation of psychological problems. The DT and Psychosocial Distress Questionnaire-Breast Cancer showed acceptable performances for the prediction of depression and anxiety assessed by the HADS. CONCLUSION: This systematic review found psychiatric assessment tools with acceptable reliability and validity for breast cancer patients. However, comparative studies on reliability and validity of various scales are required to provide useful information for the selection of appropriate assessment tools based on the clinical settings and treatment stages of breast cancer. Joint research among the fields of psychiatry and breast surgery is needed for research to establish the convergent, concurrent, and predictive validity of psychiatric assessment tools in breast cancer patients.

Temporary blindness caused by corneal edema after a local anesthetic injection in the eyebrow region: a case report.

Plastic surgery around the eyes is usually performed under local anesthesia, using a mixture of lidocaine and epinephrine. Blindness is a rare but devastating complication after the injection of local anesthesia in this region. Most cases reported to date have been caused by occlusion of the ophthalmic artery or central retinal artery. In this case report, however, we present a highly unusual case of blindness caused by corneal edema after a local anesthetic injection. A patient visited the emergency room with a laceration on the eyebrow, and local anesthesia was injected before suturing. Immediately after the injection, severe corneal edema developed, making it impossible to observe the structures in the anterior chamber in detail or check the light reflex and visual acuity of the naked eye. An antibiotic (moxifloxacin hydrochloride) and high-concentration steroid eyedrops were promptly applied. High-concentration steroids were also administered orally. On day 13 post-injury, the visual acuity of the naked eye improved to 1.0, and no recurrence of corneal lesions was observed. Although the cause of corneal edema after the local injection could not be conclusively identified, we hope that this report will help raise clinicians' awareness of this complication and appropriate treatment methods.

Characterization of breast cancer subtypes based on quantitative assessment of intratumoral heterogeneity using dynamic contrast-enhanced and diffusion-weighted magnetic resonance imaging.

OBJECTIVE: To investigate whether intratumoral heterogeneity, assessed via dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging (DWI), reflects the molecular subtypes of invasive breast cancers. MATERIAL AND METHODS: We retrospectively evaluated data from 248 consecutive women (mean age ± standard deviation, 54.6 ± 12.2 years) with invasive breast cancer who underwent preoperative DCE-MRI and DWI between 2019 and 2020. To evaluate intratumoral heterogeneity, kinetic heterogeneity (a measure of heterogeneity in the proportions of tumor pixels with delayed washout, plateau, and persistent components within a tumor) was assessed with DCE-MRI using a commercially available computer-aided diagnosis system. Apparent diffusion coefficients (ADCs) were obtained using a region-of-interest technique, and ADC heterogeneity was calculated using the following formula: (ADCmax-ADCmin)/ADCmean. Possible associations between imaging-based heterogeneity values and breast cancer subtypes were analyzed. RESULTS: Of the 248 invasive breast cancers, 61 (24.6%) were classified as luminal A, 130 (52.4%) as luminal B, 25 (10.1%) as HER2-enriched, and 32 (12.9%) as triple-negative breast cancer (TNBC). There were significant differences in the kinetic and ADC heterogeneity values among tumor subtypes (p < 0.001 and p = 0.023, respectively). The TNBC showed higher kinetic and ADC heterogeneity values, whereas the HER2-enriched subtype showed higher kinetic heterogeneity values compared to the luminal subtypes. Multivariate linear analysis showed that the HER2-enriched (p < 0.001) and TNBC subtypes (p < 0.001) were significantly associated with higher kinetic heterogeneity values. The TNBC subtype (p = 0.042) was also significantly associated with higher ADC heterogeneity values. CONCLUSIONS: Quantitative assessments of heterogeneity in enhancement kinetics and ADC values may provide biological clues regarding the molecular subtypes of breast cancer. KEY POINTS: • Higher kinetic heterogeneity was associated with HER2-enriched and triple-negative breast cancer. • Higher ADC heterogeneity was associated with triple-negative breast cancer. • Aggressive breast cancer subtypes exhibited higher intratumoral heterogeneity based on MRI.

Usefulness of using additional ultrasonic dissection device in breast cancer surgery: a retrospective cohort study.

BACKGROUND: In breast cancer surgery, electrocautery (EC) is commonly used with the basic method of knot tying, and there are few reports of using other devices such as ultrasonic dissection device (UDD). This study was designed to compare the case of using EC with the basic method of knot tying and the case of using UDD in breast cancer surgery. METHODS: From April 2019 to March 2020, 376 patients who underwent breast cancer surgery at Pusan National University Hospital were enrolled. We compared operation time, complications, and blood loss volume between surgery with and without UDD. RESULTS: We included 306 patients for the final analysis, 142 in the control group and 164 in the trial group. The operation time [minutes (min)] was significantly reduced in the trial group compared to the control group (111.2 vs. 95.5 min, P<0.001). In subgroup analysis, the operation time in the trial group was significantly reduced. There was no significant difference in intraoperative blood loss (P=0.999) and complications [seroma (P=0.965), hematoma (P=0.999), cellulitis (P=0.999)]. CONCLUSIONS: Our study showed that the use of a UDD for surgeons to select instruments for breast cancer surgery may be a good option for both patients and surgeons.

Correlation of ICG lymphography and lymphoscintigraphy severity stage in secondary upper limb lymphedema.

PURPOSE: To examine the correlation between lymphedema severity stages on lymphoscintigraphy and on indocyanine green (ICG) lymphography in patients with secondary lymphedema after breast cancer. MATERIALS AND METHODS: This retrospective study was conducted on patients who underwent both lymphoscintigraphy and ICG lymphography for the evaluation of secondary lymphedema after breast cancer. The images were classified into type I - V according to the Arm Dermal Backflow (ADB) stage and modified MD Anderson Cancer Center (MDACC) stage on ICG lymphography and lymphoscintigraphy images on the basis of how lymphatic flow was preserved and how dermal back flow was extended. The correlation between scales was analysed. RESULTS: A total of 47 patients were referred to our hospital for the evaluation of secondary lymphedema after breast cancer. There was no significant difference between lymphoscintigraphy severity scale and ADB stage (anterior and posterior). The lymphoscintigraphy severity scale and modified MDACC stage were significantly different. In the correlation analysis, lymphoscintigraphy and ADB (anterior) stage (r = 0.83), lymphoscintigraphy and ADB (posterior) stage (r = 0.86) and lymphoscintigraphy and modified MDACC stage (r = 0.85) exhibited very strong positive correlations. Intra-rater agreement between lymphoscintigraphy and ADB (anterior) stage and lymphoscintigraphy and ADB (posterior) was substantial (κ=0.62 and κ=0.69, respectively) and fair (κ = 0.36) between lymphoscintigraphy and modified MDACC stage. CONCLUSION: Lymphoscintigraphy severity stage and ADB stage on ICG lymphography showed very strong positive correlation and substantial agreement. These two modalities can work synergistically to evaluate lymphedema severity.

Recurrent late seroma after immediate breast reconstruction with latissimus dorsi musculocutaneous flap.

The latissimus dorsi musculocutaneous flap (LDMCF) is widely used for breast reconstruction. However, it has the disadvantage of frequent seroma formation at the donor site, and late seroma has also been reported. The authors report histological findings after the surgical treatment of a late, repeatedly recurrent seroma at 10 years after breast reconstruction with LDMCF. In 2008, a 66-year-old female patient underwent immediate breast reconstruction with LDMCF. In 2015, a late seroma was found at the donor site. After aspiration and drainage, the seroma recurred again in 2018. Total surgical excision of the seroma was performed and bloody-appearing fluid was identified in the capsule. The excised tissue was biopsied. Histological examination revealed no evidence of blood in the fluid, and multinucleated giant cells with amorphous eosinophilic proteinaceous material were identified. The cyst was suggestive of chronic granulomatous inflammation. There was no recurrence at 8 months postoperatively. The patient described herein underwent surgical treatment of late seroma that recurred after immediate breast reconstruction with LDMCF, and histological findings were identified. These results may be helpful for other future studies regarding late seroma after breast reconstruction with LDMCF.

Diffusion-weighted MRI of estrogen receptor-positive, HER2-negative, node-negative breast cancer: association between intratumoral heterogeneity and recurrence risk.

OBJECTIVES: To investigate possible associations between quantitative apparent diffusion coefficient (ADC) metrics derived from whole-lesion histogram analysis and breast cancer recurrence risk in women with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative, node-negative breast cancer who underwent the Oncotype DX assay. METHODS: This retrospective study was conducted on 105 women (median age, 48 years) with ER-positive, HER2-negative, node-negative breast cancer who underwent the Oncotype DX test and preoperative diffusion-weighted imaging (DWI). Histogram analysis of pixel-based ADC data of whole tumors was performed, and various ADC histogram parameters (mean, 5th, 25th, 50th, 75th, and 95th percentiles of ADCs) were extracted. The ADC difference value (defined as the difference between the 5th and 95th percentiles of ADCs) was calculated to assess intratumoral heterogeneity. Associations between quantitative ADC metrics and the recurrence risk, stratified using the Oncotype DX recurrence score (RS), were evaluated. RESULTS: Whole-lesion histogram analysis showed that the ADC difference value was different between the low-risk recurrence (RS < 18) and the non-low-risk recurrence (RS ≥ 18; intermediate to high risk of recurrence) groups (0.600 × 10-3 mm2/s vs. 0.746 × 10-3 mm2/s, p < 0.001). Multivariate regression analysis demonstrated that a lower ADC difference value (< 0.559 × 10-3 mm2/s; odds ratio [OR] = 5.998; p = 0.007) and a small tumor size (≤ 2 cm; OR = 3.866; p = 0.012) were associated with a low risk of recurrence after adjusting for clinicopathological factors. CONCLUSIONS: The ADC difference value derived from whole-lesion histogram analysis might serve as a quantitative DWI biomarker of the recurrence risk in women with ER-positive, HER2-negative, node-negative invasive breast cancer. KEY POINTS: • A lower ADC difference value and a small tumor size were associated with a low risk of recurrence of breast cancer. • The ADC difference value could be a quantitative marker for intratumoral heterogeneity. • Whole-lesion histogram analysis of the ADC could be helpful for discriminating the low-risk from non-low-risk recurrence groups.

Risk stratification system for groups with a low, intermediate, and high risk of subsequent distant metastasis and death following isolated locoregional recurrence of breast cancer.

PURPOSE: This study aimed to identify prognostic factors for long-term outcomes among patients with isolated locoregional recurrence (ILRR) of breast cancer as their first failure event. Many prognostic tools have been developed to inform systemic treatment choices in the adjuvant setting, but tools for predicting post-ILRR prognosis are scarce. METHODS: A total of 495 patients who experienced ILRR after primary surgery at the Asan Medical Center between 1989 and 2008 were included. All patient information and tumor characteristics at the initial surgery were retrieved from our retrospectively collected database, and ILRRs were categorized as local recurrence or regional recurrence (RR). Distant metastasis-free survival (DMFS), breast cancer-specific survival (BCSS), and overall survival post-ILRR were calculated. RESULTS: The median follow-up from the ILRR was 65 months (range 1-249 months), and the 5-year post-ILRR DMFS rate was 58.9%. We found three factors-lymph node metastasis, a disease-free interval < 30 months, and RR as the ILRR type-that were independent prognostic factors for both DMFS [hazard ratio (HR) = 2.08, 1.60, and 1.59; P < 0.001, 0.002, and 0.003, respectively] and BCSS (HR = 2.28, 1.99, and 1.48; P < 0.001, < 0.001, and 0.016, respectively) post-ILRR. Patients were classified into four groups according to the presence these three prognostic indicators: the low-, intermediate-, high-, and extremely high-risk groups. The 5-year post-ILRR DMFS rates were 79.4%, 68.1%, 47.6%, and 36.0%, respectively. CONCLUSIONS: This risk stratification system for subsequent distant metastases after ILRR can be used to make more informed decisions regarding prognosis-based local or systemic management strategies.

The feasibility of quantitative parameters of lymphoscintigraphy without significant dermal backflow for the evaluation of lymphedema in post-operative patients with breast cancer.

PURPOSE: We aimed to evaluate the potential role of quantitative methods associated with lymphoscintigraphy for the assessment of severity of lymphedema post-operatively in patients with breast cancer who did not show definite dermal backflow activity on the lymphoscintigraphy. METHODS: We evaluated 47 lymphoscintigraphies without dermal backflow in patients with lymphedema who received a mastectomy and axillary dissection or sentinel lymph node dissection for invasive ductal carcinoma of the breast. The quantitative asymmetry indices (QAIs) of both arms were calculated for each axilla, upper arm, forearm, and the whole arm. The QAI was defined as the radiopharmaceutical uptake ratio of the affected side to the unaffected side. Arm circumference was measured at four locations per arm to identify the maximal circumference difference (MCD) between affected and unaffected sides. RESULTS: The total and forearm QAIs of each side arm were significantly higher in the group with above moderate stage lymphedema compared with the mild stage group. Previous radiotherapy also had a significant effect on radiotracer retention expressed as QAI. The MCD was significantly correlated with QAI values of the forearm and the whole arm. The QAI of axillary areas was not significantly correlated with circumferential measurements of the arm. CONCLUSIONS: The QAIs have significant value for the diagnosis and severity of lymphedema and may therefore potentially be used as an objective tool for the assessment of lymphedema.

A novel technique for placing titanium mesh with porous polyethylene via the endoscopic transnasal approach into the orbit for medial orbital wall fractures.

BACKGROUND: The endoscopic transnasal approach is widely used for reconstructing the medial orbital wall by filling it with a silicone sheet or Merocel, but this technique has the disadvantage of retaining the packing for a long time. To overcome this drawback, a method of positioning an absorbable plate in the orbit has been introduced, but there is a risk of defect recurrence after the plate is absorbed. Here, the authors report the results of a novel surgical technique of placing a nonabsorbable titanium mesh with porous polyethylene into the orbit through the endoscopic transnasal approach. METHODS: Fourteen patients underwent surgery using the endoscopic transnasal approach. Preoperative computed tomography (CT) was used to calculate the size of the bone defect due to the fracture, and the titanium mesh was designed to be shorter than the anteroposterior length of the defect and longer than its height. The titanium mesh was inserted into the orbit under an endoscopic view. The authors then confirmed that the titanium mesh supported the orbital contents by pressing the eyeball and finished the operation. Immediately after surgery, CT results were evaluated. RESULTS: Postoperative CT scans confirmed that the titanium mesh was well-inserted and in the correct position. All patients were discharged without any complications. CONCLUSIONS: We obtained satisfactory results by inserting a titanium mesh with porous polyethylene into the orbit via the transnasal approach endoscopically.

Concordance in postsurgical radioactive iodine therapy recommendations between Watson for Oncology and clinical practice in patients with differentiated thyroid carcinoma.

BACKGROUND: To the authors' knowledge, the indications for radioactive iodine (RAI) therapy in patients with differentiated thyroid carcinoma (DTC) are unclear; treatment decisions are based on physician judgment. The objective of the current study was to identify the degree of concordance between postsurgical RAI therapy recommended by Watson for Oncology (WFO), a clinical decision support system for oncological therapy, and that recommended by physicians for patients with DTC. METHODS: The current retrospective cohort study included 207 patients with DTC who underwent thyroidectomy between 2017 and 2018. Treatment recommendations were considered concordant if WFO rendered recommendations consistent with those of the physicians. RESULTS: Treatment recommendations were concordant for 160 patients (77%). The concordance rate significantly differed according to the American Thyroid Association (ATA) risk category (P < .001) and American Joint Committee on Cancer TNM stage (seventh edition; P = .004). Logistic regression analysis demonstrated that treatment recommendations were significantly less likely to be concordant in patients with ATA intermediate-risk and stage III disease compared with those with ATA low-risk and stage I disease (odds ratio, 0.16 [P < .001] and OR, 0.35 [P = .004], respectively). CONCLUSIONS: The authors believe the concordance rate between postsurgical RAI therapy recommendations rendered by WFO and those rendered by physicians was too low to justify adopting WFO for the comprehensive screening of patients with DTC. This is particularly true among patients with ATA intermediate-risk and stage III disease, reflecting differences in practice patterns between the United States (where WFO was calibrated) and Korea. Hence, WFO is not a substitute for physicians, and also may require regional customization to improve its assistive capability.

Diffusion-weighted Imaging of Invasive Breast Cancer: Relationship to Distant Metastasis-free Survival.

Background Combined minimum apparent diffusion coefficient (ADC) and ADC difference value may improve the diagnostic performance of breast diffusion-weighted imaging (DWI) compared with mean ADC. Purpose To investigate whether ADC parameters at DWI are associated with distant metastasis-free survival in women with invasive breast cancer. Materials and Methods Between 2013 and 2014, 258 consecutive women (mean age ± standard deviation, 50.9 years ± 10.5; age range, 23-85 years) with newly diagnosed invasive breast cancer who underwent preoperative MRI with DWI were evaluated. All DWI examinations were retrospectively reviewed by two radiologists blinded to clinical information. The mean, minimum, and maximum ADCs were measured by manually placing regions of interest within the lesions, and the ADC difference value (the difference between minimum and maximum ADCs) was calculated to evaluate intratumoral heterogeneity. Cox proportional hazards models were used to determine the associations between ADC parameters and distant metastasis-free survival after adjustment for clinical-pathologic factors. Results In 25 of the 258 women (9.7%), distant metastasis developed at a median follow-up of 51 months. The ADC difference value was higher in women with distant metastasis than in those without distant metastasis (mean, 0.743 × 10-3 mm2/sec vs 0.566 × 10-3 mm2/sec, respectively; P < .001). Multivariable Cox proportional hazards analysis showed that a higher ADC difference value (>0.698 × 10-3 mm2/sec) (hazard ratio [HR], 4.5; 95% confidence interval [CI]: 2.0, 10.0; P < .001), presence of axillary node metastasis (HR, 3.3; 95% CI: 1.2, 9.3; P = .02), and estrogen receptor negativity (HR, 2.6; 95% CI: 1.2, 5.7; P = .02) were associated with poorer distant metastasis-free survival. Conclusion A higher apparent diffusion coefficient difference value at diffusion-weighted imaging is associated with poorer distant metastasis-free survival of women with invasive breast cancer. © RSNA, 2019 See also the editorial by Taourel in this issue.

Sentinel node biopsy after neoadjuvant chemotherapy for breast cancer with axillary node metastasis: A survey of clinical practice.

BACKGROUND: A survey of breast surgeons was conducted to evaluate changes in clinical practice regarding sentinel node biopsy (SNB) among clinically node-negative patients after neoadjuvant chemotherapy for breast cancer with axillary node metastasis. METHODS: We conducted two surveys among 252 members of the Korean Breast Cancer Society. The questionnaire comprised a case presentation and two associated questions. The case outlined a woman diagnosed with right breast cancer; core needle biopsy had confirmed invasive ductal carcinoma and tumor size was 4 cm on imaging examination. Fine needle aspiration examination for axillary lymph node enlargement showed metastatic carcinoma. The patient underwent neoadjuvant chemotherapy and tumor size was decreased by 2 cm; axillary lymph node enlargement was not observed on palpitation or imaging examination. Finally, the patient underwent breast conserving surgery. Survey recipients were asked: 1. Would you perform SNB in this patient? 2. If you perform SNB and no axillary node metastasis is seen, would you perform additional axillary lymph node dissection (ALND)? RESULTS: The response rate was 28.2% (71/252) and 15.1% (38/252) in 2013 and 2017, respectively. For the first question, the SNB to ALND ratio increased significantly from 54% versus 46% in 2013 to 92% versus 8% in 2017 (p < 0.001). The proportion of surgeons performing no additional ALND versus additional ALND increased from 38% versus 54% in 2013 to 53% versus 37% in 2017, but did not reach statistical significance (p = 0.1). CONCLUSIONS: These data show that application of SNB among clinically node-negative patients after neoadjuvant chemotherapy for breast cancer with node metastasis has increased among surgeons in Korea.

The clinical impact of 21-gene recurrence score on treatment decisions for patients with hormone receptor-positive early breast cancer in Korea.

PURPOSE: The 21-gene (Oncotype DX) recurrence score (RS) assay is useful in predicting the benefits of adjuvant chemotherapy for early breast cancer patients and is widely used in Western countries. However, to date, it has not gained much popularity in East Asia. We analyzed the results from five institutions' experience from using the 21-gene assay and examined the impact of assay results on decision making of chemotherapy in Korean breast cancer patients and the associations between RS and clinicopathologic characteristics. MATERIALS AND METHODS: The 21-gene assay was performed on 212 patients with estrogen receptor-positive early breast cancer in five institutions. Each center made systemic treatment decisions both before and after the knowledge of assay results. RESULTS: Among the 212 patients, 132 (62.3%) had a low RS of < 18, 60 (28.3%) had an intermediate RS of 18-30, and 20 (9.4%) had a high RS of ≥ 31. Histologic grade, presence of micrometastases, Ki-67, and presence of lymphatic invasion were statistically associated with the RS results. Treatment decisions were changed in 115 of 212 patients (54.2%) in 109 of 212 (51.4%) from chemotherapy plus hormone therapy to hormone therapy, and in six of 212 (2.8%) from hormone therapy to chemotherapy plus hormone therapy. CONCLUSION: The 21-gene breast cancer assay proved to have a significant impact on treatment decision- making. The test reduces chemotherapy use in more than 50% of Korean estrogen receptor-positive, early breast cancer patients.