Reproductive factors and mammographic density within the International Consortium of Mammographic Density: A cross-sectional study.

BACKGROUND: Elevated mammographic density (MD) for a woman's age and body mass index (BMI) is an established breast cancer risk factor. The relationship of parity, age at first birth, and breastfeeding with MD is less clear. We examined the associations of these factors with MD within the International Consortium of Mammographic Density (ICMD). METHODS: ICMD is a consortium of 27 studies with pooled individual-level epidemiological and MD data from 11,755 women without breast cancer aged 35-85 years from 22 countries, capturing 40 country-& ethnicity-specific population groups. MD was measured using the area-based tool Cumulus. Meta-analyses across population groups and pooled analyses were used to examine linear regression associations of square-root (√) transformed MD measures (percent MD (PMD), dense area (DA), and non-dense area (NDA)) with parity, age at first birth, ever/never breastfed and lifetime breastfeeding duration. Models were adjusted for age at mammogram, age at menarche, BMI, menopausal status, use of hormone replacement therapy, calibration method, mammogram view and reader, and parity and age at first birth when not the association of interest. RESULTS: Among 10,988 women included in these analyses, 90.1% (n = 9,895) were parous, of whom 13% (n = 1,286) had ≥ five births. The mean age at first birth was 24.3 years (Standard deviation = 5.1). Increasing parity (per birth) was inversely associated with √PMD (ß: - 0.05, 95% confidence interval (CI): - 0.07, - 0.03) and √DA (ß: - 0.08, 95% CI: - 0.12, - 0.05) with this trend evident until at least nine births. Women who were older at first birth (per five-year increase) had higher √PMD (ß:0.06, 95% CI:0.03, 0.10) and √DA (ß:0.06, 95% CI:0.02, 0.10), and lower √NDA (ß: - 0.06, 95% CI: - 0.11, - 0.01). In stratified analyses, this association was only evident in women who were post-menopausal at MD assessment. Among parous women, no associations were found between ever/never breastfed or lifetime breastfeeding duration (per six-month increase) and √MD. CONCLUSIONS: Associations with higher parity and older age at first birth with √MD were consistent with the direction of their respective associations with breast cancer risk. Further research is needed to understand reproductive factor-related differences in the composition of breast tissue and their associations with breast cancer risk.

21-gene expression assay and clinical outcomes of premenopausal patients with hormone receptor-positive breast cancer.

The prognostic role of the recurrence score (RS) based on the 21-gene expression assay in premenopausal women is not well delineated, and we investigated the association of outcomes and the RS in premenopausal patients who had 21-gene expression assay at Asan Medical Center, Seoul, Korea, between June 2005 and July 2018. Invasive breast cancer-free survival (IBCFS) by STEEP version 2.0 was compared according to the RS and clinical risk factors. A total of 554 patients were included in our study and 116 patients (20.9%) had age <40 years, 238 patients (43.0%) had luminal B subtype (Ki67 ≥ 20%), and 83 patients (15.0%) had RS >25. All patients received adjuvant tamoxifen ± chemotherapy. Overall, patients with RS >25 showed trend toward worse IBCFS from multivariable analysis (adjusted HR 1.89 [95% CI: 0.95-3.73], P = .069). When comparing outcomes according to age and luminal subtypes, patients with luminal B subtype and age <40 years (n = 60) showed significantly worse outcomes compared to the others (luminal A or luminal B + age ≥40 years, n = 494; adjusted HR 2.95 [95% CI: 1.49-5.82], log-rank P < .001). Among patients with luminal B subtype and age <40 years, there was no significant association observed between IBCFS and the RS (log-rank P = .51). In conclusion, while RS >25 showed association with poor outcomes in premenopausal women, it may have less prognostic significance among those with luminal B subtype and age <40 years.

Long-term outcome in patients with nodal-positive breast cancer treated with sentinel lymph node biopsy alone after neoadjuvant chemotherapy.

PURPOSE: Sentinel lymph node biopsy (SLNB) has yet to be accepted as the standard staging procedure in node positive (cN1) breast cancer patients who had clinical complete response in the axilla (cN0) following neoadjuvant chemotherapy (NAC), due to the presumed high false negative rate associated with SLNB in such scenario. This study aimed to determine whether there is a significant difference in the axillary recurrence rate (ARR) and long-term survival in this group of patients, receiving SLNB alone versus axillary lymph node dissection (ALND). METHODS: A retrospective cohort of cN1 patients who were rendered cN0 by NAC from January 2014 to December 2018 were identified from the Asan Medical Center database. Patients' characteristics and outcomes were collected and analyzed. RESULTS: 902 cN1 patients treated with NAC and turned cN0 were identified. 477 (52.9%) patients achieved complete pathological response in the axilla (ypN0). At a median follow up of 65 months, ARR was 3.2% in the SLNB only group and 1.8% in the ALND group (p = 0.398). DFS and OS were significantly worse in patients with ALND as compared to patients with SLNB only (p = 0.011 and 0.047, respectively). We noted more patients in the ALND group had T3-4 tumor. In the subgroup analysis, we showed that in the T1-2 subgroup (n = 377), there was no statistically significant difference in DFS and OS (p = 0.242 and 0.671, respectively) between SLNB only and ALND group. CONCLUSION: Our findings suggest that cN1 patients who were converted to ypN0 following NAC may be safely treated with SLNB only.

Characteristics and risk factors of axillary lymph node metastasis of microinvasive breast cancer.

PURPOSE: To select patients who would benefit most from sentinel lymph node biopsy (SLNB) by investigating the characteristics and risk factors of axillary lymph node metastasis (ALNM) in microinvasive breast cancer (MIBC). METHODS: This retrospective study included 1688 patients with MIBC who underwent breast surgery with axillary staging at the Asan Medical Center from 1995 to 2020. RESULTS: Most patients underwent SLNB alone (83.5%). Seventy (4.1%) patients were node-positive, and the majority had positive lymph nodes < 10 mm, with micro-metastases occurring frequently (n = 37; 55%). Node-positive patients underwent total mastectomy and axillary lymph node dissection (ALND) more than breast-conserving surgery (BCS) and SLNB compared with node-negative patients (p < 0.001). In the multivariate analysis, independent predictors of ALNM included young age [odds ratio (OR) 0.959; 95% confidence interval (CI) 0.927-0.993; p = 0.019], ALND (OR 11.486; 95% CI 5.767-22.877; p < 0.001), number of lymph nodes harvested (≥ 5) (OR 3.184; 95% CI 1.555-6.522; p < 0.001), lymphovascular invasion (OR 6.831; 95% CI 2.386-19.557; p < 0.001), presence of multiple microinvasion foci (OR 2.771; 95% CI 1.329-5.779; p = 0.007), prominent lymph nodes in preoperative imaging (OR 2.675; 95% CI 1.362-5.253; p = 0.004), and hormone receptor positivity (OR 2.491; 95% CI 1.230-5.046; p = 0.011). CONCLUSION: Low ALNM rate (4.1%) suggests that routine SLNB for patients with MIBC is unnecessary but can be valuable for patients with specific risk factors. Ongoing trials for omitting SLNB in early breast cancer, and further subanalyses focusing on rare populations with MIBC are necessary.

Comparison of long-term oncological outcomes after central lumpectomy versus nipple-sparing breast-conserving surgery for centrally located breast cancer: a propensity score-matched study.

PURPOSE: To compare the oncological safety of nipple-sparing breast-conserving surgery (BCS) versus central lumpectomy for centrally located breast cancer (CLBC). METHODS: Patients who underwent BCS for CLBC at Asan Medical Center from 2007 to 2018 were reviewed retrospectively. The oncological outcomes of nipple-sparing BCS (NS-BCS) and central lumpectomy were compared using univariate and multivariate Cox regression analyses and compared again after 1:1 propensity score matching (PSM). RESULTS: The study included 306 patients who underwent NS-BCS and 106 patients who underwent central lumpectomy (median follow-up: 111 months). On multivariate analysis, central lumpectomy had a lower risk of local recurrence compared to NS-BCS, albeit without statistical significance (HR 0.14, 95% CI 0.02-1.24; p = 0.077). There was no significant difference in the risk of death (HR 0.14, 95% CI 0.01-1.68, p = 0.12). After PSM, each group had 106 patients. The 5-year and 10-year local recurrence-free survival rates were 94.2% and 92.9% for NS-BCS, and 99.1% and 99.1% for central lumpectomy, respectively (p = 0.031). There were no significant differences in overall survival, regional recurrence-free survival, or distant recurrence-free survival. Fifteen patients (4.9%) who underwent NS-BCS had ipsilateral breast tumor recurrence (IBTR), of which 40% were in the nipple-areolar complex and previous surgical sites. One patient (0.9%) who underwent central lumpectomy experienced an IBTR in a different quadrant. CONCLUSION: NS-BCS showed more local recurrence than central lumpectomy. When deciding whether to spare the nipple during BCS in CLBC, patients should be sufficiently informed about the risk of IBTR.

Oncological Safety of Skipping Axillary Lymph Node Dissection in Patients with Clinical N0, Sentinel Node-Positive Breast Cancer Undergoing Total Mastectomy.

OBJECTIVE: This study aimed to determine whether sentinel lymph node biopsy (SLNB) alone could afford oncological outcomes comparable with axillary lymph node dissection (ALND) in patients with early breast cancer without palpable lymphadenopathy who underwent total mastectomy (TM) and were SLN-positive. METHODS: This study analyzed clinical data of 6747 patients with breast cancer who underwent TM between 2014 and 2018 in two tertiary hospitals in Korea. Overall, 643 clinical stage T1-3 N0 patients who did not receive neoadjuvant therapy and had one to two metastatic SLNs at the time of surgery were included. Propensity score matching was performed between the SLNB alone and ALND groups, adjusting for clinical T stage and number of metastatic SLNs. In total, 237 patients were allocated to each group. RESULTS: Mean number of metastatic SLNs was 1.2 for the SLNB group and 1.6 for the ALND group. With a median follow-up of 65.0 months, 5 year disease-free survival was 90.8% for the SLNB group and 93.9% for the ALND group (hazard ratio [HR] 1.35, 95% confidence interval [CI] 0.70-2.58; p = 0.36). 5 year ipsilateral locoregional recurrence-free survival (LRRFS) was not significantly different between the two groups (95.1% and 98.3% for the SLNB and ALND groups, respectively) [HR 1.86, 95% CI 0.69-5.04; p = 0.21]. In the SLNB group, patients who received radiation therapy (RT) showed superior 5 year LRRFS than patients who did not receive RT (100% vs. 92.9%; p = 0.02). CONCLUSION: Collectively, our findings suggest that SLNB could afford comparable outcomes to ALND in patients with early breast cancer and one to two metastatic SLNs who underwent TM. Importantly, RT could decrease locoregional recurrence in patients who underwent SLNB alone.

Surveillance for Distant Metastasis in Breast Cancer Patients Who Underwent Contemporary Management: A Report from the Korean Breast Cancer Society Survivor Research Group.

BACKGROUND: Current guidelines recommend against the use of routine imaging tests to detect distant metastasis in asymptomatic breast cancer patients. However, recent advancements in effective therapeutics and diagnostic accuracy have raised the need to reassess the clinical efficacy of intensive metastasis surveillance. We report the results of a multicenter retrospective study to investigate the association between intensive imaging studies and survival outcomes. PATIENTS AND METHODS: We retrospectively reviewed the data of 4130 patients who underwent surgery from 11 hospitals in Korea between January 2010 and December 2011. Patients were divided into two groups on the basis of the intensity of metastasis imaging studies during their disease-free period. The types and intervals of the imaging studies were based on each physician's decisions. RESULTS: High-intensive screening showed a shorter distant metastasis-free survival [p < 0.001, hazard ratio (HR) 1.62; 95% confidence interval (CI) 1.29-2.04], especially for patients in whom bone or lung was the first site of metastasis. With a median follow-up period of 110.0 months, the 5-year breast cancer-specific survival (BCSS) rate was 96.5%. The high-intensity screening group showed significantly poorer BCSS compared with the low-intensity screening group (p < 0.001, HR 3.13; 95% CI 2.32-4.21). However, both multivariable analysis and propensity score matching analysis showed no significant association between the screening intensity and BCSS. CONCLUSIONS: Frequent imaging studies to detect distant metastasis were associated with earlier detection of distant metastasis, especially for lung and bone metastasis. However, intensive surveillance showed no apparent association with BCSS despite the use of currently available treatments.

Chemically induced cone degeneration in the 13-lined ground squirrel.

Animal models of retinal degeneration are critical for understanding disease and testing potential therapies. Inducing degeneration commonly involves the administration of chemicals that kill photoreceptors by disrupting metabolic pathways, signaling pathways, or protein synthesis. While chemically induced degeneration has been demonstrated in a variety of animals (mice, rats, rabbits, felines, 13-lined ground squirrels (13-LGS), pigs, chicks), few studies have used noninvasive high-resolution retinal imaging to monitor the in vivo cellular effects. Here, we used longitudinal scanning light ophthalmoscopy (SLO), optical coherence tomography, and adaptive optics SLO imaging in the euthermic, cone-dominant 13-LGS (46 animals, 52 eyes) to examine retinal structure following intravitreal injections of chemicals, which were previously shown to induce photoreceptor degeneration, throughout the active season of 2019 and 2020. We found that iodoacetic acid induced severe pan-retinal damage in all but one eye, which received the lowest concentration. While sodium nitroprusside successfully induced degeneration of the outer retinal layers, the results were variable, and damage was also observed in 50% of contralateral control eyes. Adenosine triphosphate and tunicamycin induced outer retinal specific damage with varying results, while eyes injected with thapsigargin did not show signs of degeneration. Given the variability of damage we observed, follow-up studies examining the possible physiological origins of this variability are critical. These additional studies should further advance the utility of chemically induced photoreceptor degeneration models in the cone-dominant 13-LGS.

A role of anterior cingulate cortex in the emergence of worker-parasite relationship.

We studied the brain mechanisms underlying action selection in a social dilemma setting in which individuals' effortful gains are unfairly distributed among group members. A stable "worker-parasite" relationship developed when three individually operant-conditioned rats were placed together in a Skinner box equipped with response lever and food dispenser on opposite sides. Specifically, one rat, the "worker," engaged in lever-pressing while the other two "parasitic" rats profited from the worker's effort by crowding the feeder in anticipation of food. Anatomically, c-Fos expression in the anterior cingulate cortex (ACC) was significantly higher in worker rats than in parasite rats. Functionally, ACC inactivation suppressed the worker's lever-press behavior drastically under social, but only mildly under individual, settings. Transcriptionally, GABAA receptor- and potassium channel-related messenger RNA expressions were reliably lower in the worker's, relative to parasite's, ACC. These findings indicate the requirement of ACC activation for the expression of exploitable, effortful behavior, which could be mediated by molecular pathways involving GABAA receptor/potassium channel proteins.

Predicting Long-Term Engagement in mHealth Apps: Comparative Study of Engagement Indices.

BACKGROUND: Digital health care apps, including digital therapeutics, have the potential to increase accessibility and improve patient engagement by overcoming the limitations of traditional facility-based medical treatments. However, there are no established tools capable of quantitatively measuring long-term engagement at present. OBJECTIVE: This study aimed to evaluate an existing engagement index (EI) in a commercial health management app for long-term use and compare it with a newly developed EI. METHODS: Participants were recruited from cancer survivors enrolled in a randomized controlled trial that evaluated the impact of mobile health apps on recovery. Of these patients, 240 were included in the study and randomly assigned to the Noom app (Noom Inc). The newly developed EI was compared with the existing EI, and a long-term use analysis was conducted. Furthermore, the new EI was evaluated based on adapted measurements from the Web Matrix Visitor Index, focusing on click depth, recency, and loyalty indices. RESULTS: The newly developed EI model outperformed the existing EI model in terms of predicting EI of a 6- to 9-month period based on the EI of a 3- to 6-month period. The existing model had a mean squared error of 0.096, a root mean squared error of 0.310, and an R2 of 0.053. Meanwhile, the newly developed EI models showed improved performance, with the best one achieving a mean squared error of 0.025, root mean squared error of 0.157, and R2 of 0.610. The existing EI exhibited significant associations: the click depth index (hazard ratio [HR] 0.49, 95% CI 0.29-0.84; P<.001) and loyalty index (HR 0.17, 95% CI 0.09-0.31; P<.001) were significantly associated with improved survival, whereas the recency index exhibited no significant association (HR 1.30, 95% CI 1.70-2.42; P=.41). Among the new EI models, the EI with a menu combination of menus available in the app's free version yielded the most promising result. Furthermore, it exhibited significant associations with the loyalty index (HR 0.32, 95% CI 0.16-0.62; P<.001) and the recency index (HR 0.47, 95% CI 0.30-0.75; P<.001). CONCLUSIONS: The newly developed EI model outperformed the existing model in terms of the prediction of long-term user engagement and compliance in a mobile health app context. We emphasized the importance of log data and suggested avenues for future research to address the subjectivity of the EI and incorporate a broader range of indices for comprehensive evaluation.