
Shayna Showalter
· Associate Professor of SurgeryVerifiedUniversity of Virginia · Molecular Physiology and Biological Physics
Active 1974–2026
Research topics
- Demography
- Medicine
- Internal medicine
- Family medicine
- Environmental health
Selected publications
2026-01-09
articleOpen access<p>Supplementary Figure 3 shows posterior predictive checks for the model predicting MCS change from diagnosis to two years. The figure includes kernel density overlays and distributions of replicated vs observed means and variances.</p>
Annals of Surgical Oncology · 2026-01-19
article2026-01-09
articleOpen access<p>Supplementary Table 3 presents the R-hat convergence diagnostics for all Bayesian models used in the study. It includes the minimum and maximum R̂ values for each model across both cohorts and outcome types (PCS and MCS). All R̂ values are close to 1, indicating excellent convergence of the Markov chains.</p>
2026-01-09
articleOpen access<div>AbstractBackground:<p>Evidence comparing patients’ health-related quality of life (HRQOL) before and after breast cancer diagnosis, and factors influencing these trajectories, is limited because of unpredictable onset. We analyzed predictors of HRQOL change in elderly patients with breast cancer across two transitions: pre- to post-diagnosis and at diagnosis versus 2 years later.</p>Methods:<p>Using Surveillance, Epidemiology, and End Results–Medicare Health Outcomes Survey linkage, we analyzed patients with breast cancer >65 years who completed two HRQOL surveys. Two cohorts were examined: patients with surveys before and within 1 year after diagnosis (cohort 1) and those with surveys within 1 year of diagnosis and 2 years after diagnosis (cohort 2). Bayesian regression identified predictors of physical component summary (PCS) and mental component summary (MCS) score changes.</p>Results:<p>In cohort 1 (<i>n</i> = 1,546), advanced stage was associated with greater HRQOL decline, with mean PCS changes ranging from −2.1 to −6.5 and MCS from −2.0 to −5.1. Baseline activities of daily living (ADL) limitations were associated with mean PCS declines ranging from −2.0 to −2.6 and mean MCS decline of −2.0. Better baseline health perception was protective with mean PCS increases ranging from +1.4 to +3.4. In cohort 2 (<i>n</i> = 891), baseline ADL limitations were associated with mean PCS declines ranging from −1.6 to −5.5 and mean MCS decline of −2.5, whereas poor health perception was associated with mean PCS decline of −3.2. Excellent health perception was protective (mean MCS: +4.1). Surgery, chemotherapy, and radiation had no HRQOL affect.</p>Conclusions:<p>Baseline health perception and ADL limitations are critical determinants of HRQOL trajectories, outweighing treatments.</p>Impact:<p>Early intervention strategies based on baseline assessments may improve survivorship.</p></div>
Fast learning-free organoid quantification and tracking with OrganoSeg2
Scientific Reports · 2026-02-09
articleOpen accessOrganoids are routinely imaged by brightfield microscopy at low magnification, but these images are challenging to analyze quantitatively at scale. Given differences in organoid-culture format and image acquisition among research groups, there is a general need for versatile segmentation algorithms that refine for specific applications. Here, we introduce OrganoSeg2, an overhauled software that substantively advances the multi-window adaptive thresholding of its predecessor. OrganoSeg2 gives users access to additional segmentation parameters that were latent in OrganoSeg, and common operations are accelerated ~10-fold. Using data from six organoid types, we find that the generalized segmentation accuracy of OrganoSeg2 surpasses multiple alternatives, including segmenters based on deep learning. OrganoSeg2 adds longitudinal single-organoid tracking and multicolor fluorescence quantification, which we use to examine growth trajectories and radiotherapy responses in luminal breast cancer organoids. OrganoSeg2 is shared freely as installation packages for current users and source code for future developers (https://github.com/JanesLab/OrganoSeg2).
2025-03-21
preprintOpen accessPurpose: Sleep quality and sexual functioning are interrelated, with problems in these domains frequent among breast cancer survivors. As there is limited evidence on how these constructs influence one another over time, this secondary analysis examines the prospective association between breast cancer survivors’ sleep quality and sexual satisfaction.Methods: 313 distressed breast cancer survivors (age M=52, 84% non-Hispanic White) were randomized to either a mobile app distress intervention (IntelliCare) or a psychoeducational control app. Participants reported sleep quality (Pittsburgh Sleep Quality Index; PSQI) and sexual satisfaction (PROMIS Satisfaction with Sex Life Scale; SWSLS) at baseline, 8 weeks, 6 months, and 12 months. Parallel process latent growth modeling was used to examine associations between constructs over time, controlling for age and partner status. Moderation by study condition was tested.Results: The final parallel process model fit the data (χ²(29)=24.47, p=.71; CFI=1.00; SRMR=.025) with no moderation effects by study condition. Both sleep quality (slope B=0.54, p&lt;.001) and sexual satisfaction (slope B=0.58, p=.004) improved over time, with worse initial scores in the domain predicting greater improvement (PSQI intercept-slope covariance: B=-1.02, p=.01; SWSLS: B=-4.62, p=.01). Sleep quality and sexual satisfaction were positively associated at baseline (PSQI-SWSLS intercept covariance B=6.74, p&lt;.001), but initial levels of one domain did not predict changes in the other, nor were the trajectories of the two domains related (ps&gt;.05).Conclusions: Poor sleep quality and sexual satisfaction were common and concurrently related in distressed breast cancer survivors, yet changes in these domains were not related. Survivors reporting concerns in one domain should be evaluated for concerns in the other; however, improving sleep or sexual satisfaction alone is unlikely to produce lasting benefits in the other domain.
medRxiv · 2025-01-29
preprintOpen accessSenior authorAbstract Background Prospective randomized data supports radiation omission in women ≥ 65 years who take adjuvant endocrine therapy (AET) following breast-conserving surgery. Many patients who omit radiation stop AET early due to side effects. In the POWER trial, a prospective single-arm study, patients took 90 days of pre-operative endocrine therapy (pre-ET) to assess tolerance before making adjuvant treatment decisions. We hypothesized that patient-reported outcomes (PROs) during pre-ET would be heterogeneous and that 90 days was sufficient time for symptoms to develop. Patients and Methods PRO data from POWER trial participants was obtained before, during, and after pre-ET, including health-related quality of life (HRQoL), depression, and ET symptoms using the EORTC-QLQ, CESD-R, and BCPT-SCL tools. PRO assessments were further analyzed after stratifying patients by high or low perceived sensitivity to medicine (PSM). Results Pre-ET PROs were assessed for 75 participants. The majority (73.3%) reported symptoms during pre-ET. Only 10.7% had symptoms severe enough to stop pre-ET before 90 days. Vasomotor (42.7%) and musculoskeletal (41.3%) symptoms were the most common. HRQoL was preserved for 66.6% participants. Patients with high PSM had more ET side effects. Conclusion Patients developed similar side effects during pre-ET as those typically seen with AET. PROs and the impact of pre-ET on HRQoL were patient-dependent. A 90-day course of pre-ET is sufficient for patients to develop symptoms reflective of long-term AET. Future analyses will assess the association of pre-ET PROs with AET initiation and adherence.
Journal of Surgical Research · 2025-10-06
articleOpen accessSenior authorAnnals of Surgical Oncology · 2025-04-10 · 1 citations
editorial1st authorCorrespondingCancer Epidemiology Biomarkers & Prevention · 2025-10-21
articleBACKGROUND: Evidence comparing patients' health-related quality of life (HRQOL) before and after breast cancer diagnosis, and factors influencing these trajectories, is limited because of unpredictable onset. We analyzed predictors of HRQOL change in elderly patients with breast cancer across two transitions: pre- to post-diagnosis and at diagnosis versus 2 years later. METHODS: Using Surveillance, Epidemiology, and End Results-Medicare Health Outcomes Survey linkage, we analyzed patients with breast cancer >65 years who completed two HRQOL surveys. Two cohorts were examined: patients with surveys before and within 1 year after diagnosis (cohort 1) and those with surveys within 1 year of diagnosis and 2 years after diagnosis (cohort 2). Bayesian regression identified predictors of physical component summary (PCS) and mental component summary (MCS) score changes. RESULTS: In cohort 1 (n = 1,546), advanced stage was associated with greater HRQOL decline, with mean PCS changes ranging from -2.1 to -6.5 and MCS from -2.0 to -5.1. Baseline activities of daily living (ADL) limitations were associated with mean PCS declines ranging from -2.0 to -2.6 and mean MCS decline of -2.0. Better baseline health perception was protective with mean PCS increases ranging from +1.4 to +3.4. In cohort 2 (n = 891), baseline ADL limitations were associated with mean PCS declines ranging from -1.6 to -5.5 and mean MCS decline of -2.5, whereas poor health perception was associated with mean PCS decline of -3.2. Excellent health perception was protective (mean MCS: +4.1). Surgery, chemotherapy, and radiation had no HRQOL affect. CONCLUSIONS: Baseline health perception and ADL limitations are critical determinants of HRQOL trajectories, outweighing treatments. IMPACT: Early intervention strategies based on baseline assessments may improve survivorship.
Recent grants
NIH · $382k · 2018–2023
Postdoctoral Training Grant for MDs in Surgical Oncology Research
NIH · $4.1M · 2011–2026
NIH · $1.5M · 2018–2025
Frequent coauthors
- 144 shared
M Tsukamura
- 144 shared
H. W. B. Engel
- 144 shared
E WOLINSKY
- 144 shared
W Käppler
- 144 shared
Alfred G. Karlson
- 144 shared
H. H. Kleeberg
South African Medical Research Council
- 144 shared
K. H. Schröder
- 144 shared
C. McDURMONT
United States Department of State
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