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Open Access Publications from the University of California

Scholarly Works (23 results)

  • Thesis
  • Peer Reviewed
UC San Francisco Electronic Theses and Dissertations (2018)

Cancer is the second leading cause of death in the United States, with cancer of the breast and cancer of the lung and bronchus together accounting for approximately 29% of all cancer cases and 32% of all cancer deaths. Cancer screening tests are a means to reduce mortality of these two cancer types. While the current guidelines aim to maximize the potential benefits from screening while minimizing harms, there is still significant effort needed to achieve optimal breast and lung cancer screening uptake. This dissertation builds upon recent research leveraging multilevel frameworks to examine factors affecting cancer screening use and their importance in clinical practice and in screening guidelines.

The first chapter comprehensively examines the current evidence regarding how various life expectancy factors are associated with screening mammography uptake among women ages 65 and older. The primary objective was to understand the important role life expectancy could play in patient-provider communication regarding whether to continue screening at an advanced age. The second chapter focuses on the variation in performance of lung cancer screening scans, which use low-dose computed tomography. This project sought to identify the potential institutional-level predictors that could lead to radiation doses outside the current guidelines for these scans, potentially impacting the expected margin of benefit from screening. The third and final chapter is a multilevel assessment of the effect of employment status on screening mammography utilization during the Great Recession, to better understand how societal changes can influence individual-level cancer screening behaviors.

Together these projects highlight the interdependence of factors at multiple levels in the cancer screening environment. Examination of these multilevel factors can improve integration of new interventions to optimize cancer screening uptake and ensure that early detection practices are successful, thus improving treatment outcomes and maximizing survival.

    Cover page: Multilevel Factors in Cancer Screening
    • Article
    • Peer Reviewed
    UC San Francisco Previously Published Works (2016)

    Background

    Approximately half of new invasive breast cancer cases diagnosed each year in the United States occur among women aged 65 years and older. The increasing life expectancy coupled with the attendant rise in breast cancer incidence and elimination of out-of-pocket expenses for screening mammography as a result of the Affordable Care Act could lead to higher utilization rates of screening mammography. Although research indicates that life expectancy should be a strong consideration when making screening decisions among older women, the extent to which screening mammography utilization is tailored to comorbidity and life expectancy is not well established.

    Methods/design

    To identify relevant studies, a systematic search of the literature will be conducted using PubMed and EMBASE between January 1, 1991, and March 1, 2016. Additional studies will be found through citation review or by contacting experts in the field. The inclusion criteria will be any study design comprised of women aged 65 and older, assessing women's comorbidity, functional impairments, and/or health status, and reporting outcome measures that addressed mammography utilization within the last 1-5 years. For each study, two authors will independently abstract data regarding study eligibility and outcomes to determine relevance. Quantitative results will be extracted from text and tables, choosing preferably those adjusted for important confounders.

    Discussion

    The review will provide evidence on the impact of comorbidity, functional limitations, and health status on screening mammography utilization in older women and inform decision aids in this area.

    Systematic review registration

    PROSPERO CRD42016032661.
      Cover page: Utilization of screening mammography in older women according to comorbidity and age: protocol for a systematic review
      • Article
      • Peer Reviewed
      UC San Diego Previously Published Works (2021)

      Background and aims

      The optimal time interval for diagnostic colonoscopy completion after an abnormal stool-based colorectal cancer (CRC) screening test is uncertain. We examined the association between time to colonoscopy and CRC outcomes among individuals who underwent diagnostic colonoscopy after abnormal stool-based screening.

      Methods

      We performed a retrospective cohort study of veterans age 50 to 75 years with an abnormal fecal occult blood test (FOBT) or fecal immunochemical test (FIT) between 1999 and 2010. We used multivariable Cox proportional hazards to generate CRC-specific incidence and mortality hazard ratios (HRs) and 95% confidence intervals (CI) for 3-month colonoscopy intervals, with 1 to 3 months as the reference group. Association of time to colonoscopy with late-stage CRC diagnosis was also examined.

      Results

      Our cohort included 204,733 patients. Mean age was 61 years (SD 6.9). Compared with patients who received a colonoscopy at 1 to 3 months, there was an increased CRC risk for patients who received a colonoscopy at 13 to 15 months (HR 1.13; 95% CI 1.00-1.27), 16 to 18 months (HR 1.25; 95% CI 1.10-1.43), 19 to 21 months (HR 1.28; 95% CI: 1.11-1.48), and 22 to 24 months (HR 1.26; 95% CI 1.07-1.47). Compared with patients who received a colonoscopy at 1 to 3 months, mortality risk was higher in groups who received a colonoscopy at 19 to 21 months (HR 1.52; 95% CI 1.51-1.99) and 22 to 24 months (HR 1.39; 95% CI 1.03-1.88). Odds for late-stage CRC increased at 16 months.

      Conclusions

      Increased time to colonoscopy is associated with higher risk of CRC incidence, death, and late-stage CRC after abnormal FIT/FOBT. Interventions to improve CRC outcomes should emphasize diagnostic follow-up within 1 year of an abnormal FIT/FOBT result.
        Cover page: Time to Colonoscopy After Abnormal Stool-Based Screening and Risk for Colorectal Cancer Incidence and Mortality
        • Article
        • Peer Reviewed
        UC San Diego Previously Published Works (2021)

        Objective

        Young-onset colorectal cancer (YCRC) incidence is rising. Scant data exist on YCRC risk after presentation with concerning symptoms such as iron-deficiency anaemia (IDA) or haematochezia. We examined the association between IDA and YCRC, and haematochezia and YCRC.

        Design

        Cohort study of US Veterans aged 18-49 years receiving Veterans Health Administration (VHA) care 1999-2016. IDA analytic cohort was created matching individuals without incident IDA to those with IDA 4:1 based on sex, birth year and first VHA visit date (n=239 000). We used this approach to also create a distinct haematochezia analytic cohort (n=653 740). Incident YCRC was ascertained via linkage to cancer registry and/or cause-specific mortality data. We computed cumulative incidence, risk difference (RD) and HRs using Cox models in each cohort.

        Results

        Five-year YCRC cumulative incidence was 0.45% among individuals with IDA versus 0.05% without IDA (RD: 0.39%, 95% CI: 0.33%-0.46%), corresponding to an HR of 10.81 (95% CI: 8.15-14.33). Comparing IDA versus no IDA, RD was 0.78% for men (95% CI: 0.64%-0.92%) and 0.08% for women (95% CI: 0.03%-0.13%), and RD increased by age from 0.14% for <30 years to 0.53% for 40-49 years. YCRC cumulative incidence was 0.33% among individuals with haematochezia versus 0.03% without haematochezia (RD: 0.30%, 95% CI: 0.26%-0.33%), corresponding to an HR of 10.66 (95% CI: 8.76-12.97). Comparing haematochezia versus no haematochezia, RD increased by age from 0.04% for <30 years to 0.43% for 40-49 years.

        Conclusion

        Colonoscopy should be strongly considered in adults aged <50 years with IDA or haematochezia without a clinically confirmed alternate source.
          Cover page: Young-onset colorectal cancer risk among individuals with iron-deficiency anaemia and haematochezia
          • Article
          • Peer Reviewed
          UC San Diego Previously Published Works (2021)
          Rising trends in the incidence and mortality of early-onset colorectal cancer (CRC) in those who are younger than 50 years have been well established. These trends have spurred intense investigation focused on elucidating the epidemiology and characteristics of early-onset CRC, as well as on identifying strategies for early detection and prevention. In this review, we provide a contemporary update on early-onset CRC with a particular focus on epidemiology, molecular characterization, red flag signs and symptoms, and screening for early-onset CRC.
            Cover page: An Update on the Epidemiology, Molecular Characterization, Diagnosis, and Screening Strategies for Early-Onset Colorectal Cancer
            • Article
            • Peer Reviewed
            UC San Diego Previously Published Works (2022)

            Background

            Early onset colorectal cancer (CRC) incidence is rising under age 50, with a birth cohort effect for increasing incidence among individuals born 1950 and later. It is unclear whether increasing incidence trends will confer increased risk beyond age 50, the previously most commonly recommended age to initiate screening, when screening availability might modify incidence trends.

            Aim

            Evaluate US trends in colorectal cancer (CRC) for ages 40-59 years.

            Methods

            We analyzed counts and incidence rates for CRC, including by anatomic subsite, using the US Cancer Statistics dataset covering 100% of the population 2003-2017. Joinpoint regression was used to quantify Average Annual Percent Change (AAPC) in cancer incidence by age subgroup.

            Results

            470,458 CRC cases were observed age 40-59, with absolute numbers of rectal (n = 4173) and distal cases (n = 3327) per year for age 50-54 approaching age 55-59 cases for rectal (n = 4566) and distal (n = 3682) cancer by 2017. Increasing early onset rectal cancer incidence per 100,000 occuring under age 50 was observed to extend to age 50-54, from 4.9 to 6.3 for age 40-44 (AAPC 2.1; 95% CI 1.5-2.7), 9.3 to 12.0 for age 45-49 (AAPC 1.5; 95% CI 1.1-1.4), and from 16.7 to 19.5 for age 50-54 (AAPC 1.0; 95% CI 0.7-1.3).

            Conclusions

            CRC trends suggest observed increased risks under age 50 are also present after age 50, despite prior availability of screening for this group. Recent CRC trends support initiation of screening earlier than age 50, and promotion of "on-time" screening initiation.
              Cover page: Increasing Colorectal Cancer Incidence Before and After Age 50: Implications for Screening Initiation and Promotion of “On-Time” Screening
              • Article
              • Peer Reviewed
              UC San Francisco Previously Published Works (2018)

              Study design

              Secondary analysis of prospective, multicenter data.

              Objective

              To evaluate impact of sagittal parameters on health-related quality of life (HRQoL) in adults with lumbosacral spondylolisthesis.

              Methods

              Adults with unoperated lumbosacral spondylolisthesis were identified in the Spinal Deformity Study Group database. Pearson's correlations were calculated between SF-12 (Short Form-12)/Scoliosis Research Society-30 (SRS-30) scores and radiographic parameters (C7 sagittal vertical axis [SVA] deviation, T1 pelvic angle, pelvic tilt [PT], pelvic incidence, sacral slope, slip angle, Meyerding slip grade, Labelle classification). Main effects linear regression models measured association between individual health status measures and individual radiographic predictor variables.

              Results

              Forty-five patients were analyzed (male, 15; female, 30; average age 40.5 ± 18.7 years; 14 low-grade, 31 high-grade). For low-grade slips, SVA had strong negative correlations with SF-12 mental component score (MCS), SRS-30 appearance, mental, and satisfaction domains (r = -0.57, r = -0.60, r = -0.58, r = -0.53, respectively; P < .05). For high-grade slips, slip angle had a moderate negative correlation with SF-12 MCS (r = -0.36; P = .05) and SVA had strong negative correlations with SF-12 physical component score (PCS), SRS-30 appearance and activity domains (r = -0.48, r = -0.48, r = -0.45; P < .05) and a moderate negative correlation with SRS-30 total (r = -0.37; P < .05). T1 pelvic angle had a moderate negative correlation with SF-12 PCS and SRS-30 appearance (r = -0.37, r = -0.36; P ≤ .05). For every 1° increase in PT, there was a 0.04-point decrease in SRS appearance, 0.05-point decrease in SRS activity, 0.06-point decrease in SRS satisfaction, and 0.04-point decrease in SRS total score (P < .05).

              Conclusion

              Lumbosacral spondylolisthesis in adults negatively affects HRQoL. Multiple radiographic sagittal parameters negatively affect HRQoLs for patients with low- and high-grade slips. Improvement of sagittal parameters is an important goal of surgery for adults with lumbosacral spondylolisthesis.
                Cover page: Correlation Between Lumbopelvic and Sagittal Parameters and Health-Related Quality of Life in Adults With Lumbosacral Spondylolisthesis.
                • Article
                • Peer Reviewed
                UC San Francisco Previously Published Works (2018)

                Background

                The extent to which screening mammography (SM) recommendations in older women incorporate life expectancy factors is not well established.

                Objective

                The objective of this review was to evaluate evidence on SM utilization in older women by life expectancy factors.

                Data sources

                We searched Medline, Embase and Web of Science from January 1991 to March 2016.

                Study selection

                We included studies examining SM utilization in women ages ≥65 years that measured life expectancy using comorbidity, functional limitations or health or prognostic status.

                Data extraction and synthesis

                ORs and 95% CIs were extracted and grouped by life expectancy category. Findings were aggregated into pooled ORs and 95% CIs and meta-analyzed by life expectancy category.

                Main outcomes and measures

                The primary outcome was SM utilization within the last 5 years. Life expectancy factors included number of comorbidities, Charlson Comorbidity Index (CCI), activities of daily living, instrumental activities of daily living, self-reported health status and 5-year prognostic indices.

                Results

                Of 2,606 potential titles, we identified 25 meeting the inclusion criteria (comorbidity: eight studies, functional status: 11 studies and health/prognostic status: 13 studies). Women with higher CCI scores had decreased SM utilization (pooled OR: 0.75, 95% CI: 0.67-0.85), but increased absolute number of comorbidities were weakly associated with increased SM utilization (pooled OR: 1.17, 95% CI: 1.00-1.36). Women with more functional limitations had lower SM use odds than women with no limitations (pooled OR: 0.72, 95% CI: 0.62-0.83). Screening utilization odds were lower among women with poor vs excellent health (pooled OR: 0.85, 95% CI: 0.74-0.96).

                Conclusion

                Greater CCI score, functional limitations and lower perceived health were associated with decreased SM use, whereas higher absolute number of comorbidities was associated with increased SM use. SM guidelines should consider these factors to improve assessments of potential benefits and harms in older women.
                  Cover page: Screening mammography use in older women according to health status: a systematic review and meta-analysis
                  • Article
                  • Peer Reviewed
                  UC San Diego Previously Published Works (2019)

                  Objective

                  To conduct an anatomic site-specific case-control study of candidate colorectal cancer (CRC) risk factors.

                  Design

                  Case-control study of US veterans with >1 colonoscopy during 1999-2011. Cases had cancer registry-identified CRC at colonoscopy, while controls were CRC free at colonoscopy and within 3 years of colonoscopy. Primary outcome was CRC, stratified by anatomic site: proximal, distal, or rectal. Candidate risk factors included age, sex, race/ethnicity, body mass index, height, diabetes, smoking status, and aspirin exposure summarised by adjusted ORs and 95% CIs.

                  Results

                  21 744 CRC cases (n=7017 rectal; n=7039 distal; n=7688 proximal) and 612 646 controls were included. Males had significantly higher odds relative to females for rectal cancer (OR=2.84, 95% CI 2.25 to 3.58) than distal cancer (OR=1.84, 95% CI 1.50 to 2.24). Relative to whites, blacks had significantly lower rectal cancer odds (OR=0.88, 95% CI 0.82 to 0.95), but increased distal (OR=1.27, 95% CI 1.19 to 1.37) and proximal odds (OR=1.62, 95% CI 1.52 to 1.72). Diabetes prevalence was more strongly associated with proximal (OR=1.29, 95% CI 1.22 to 1.36) than distal (OR=1.15, 95% CI 1.08 to 1.22) or rectal cancer (OR=1.12, 95% CI 1.06 to 1.19). Current smoking was more strongly associated with rectal cancer (OR=1.81, 95% CI 1.68 to 1.95) than proximal cancer (OR=1.53, 95% CI 1.43 to 1.65) or distal cancer (OR=1.46, 95% CI 1.35 to 1.57) compared with never smoking. Aspirin use was significantly more strongly associated with reduced rectal cancer odds (OR=0.71, 95% CI 0.67 to 0.76) than distal (OR=0.85, 95% CI 0.81 to 0.90) or proximal (OR=0.91, 95% CI 0.86 to 0.95).

                  Conclusion

                  Candidate CRC risk factor associations vary significantly by anatomic site. Accounting for site may enable better insights into CRC pathogenesis and cancer control strategies.
                    Cover page: Risk factors for colorectal cancer significantly vary by anatomic site
                    • Article
                    • Peer Reviewed
                    UC San Francisco Previously Published Works (2023)

                    Purpose

                    To develop a model for factors predictive of Post-Acute Care Facility (PACF) discharge in adult patients undergoing elective multi-level (≥ 3 segments) lumbar/thoracolumbar spinal instrumented fusions.

                    Methods

                    The State Inpatient Databases acquired from the Healthcare Cost and Utilization Project from 2005 to 2013 were queried for adult patients who underwent elective multi-level thoracolumbar fusions for spinal deformity. Outcome variables were classified as discharge to home or PACF. Predictive variables included demographic, pre-operative, and operative factors. Univariate and multivariate logistic regression analyses informed development of a logistic regression-based predictive model using seven selected variables. Performance metrics included area under the curve (AUC), sensitivity, and specificity.

                    Results

                    Included for analysis were 8866 patients. The logistic model including significant variables from multivariate analysis yielded an AUC of 0.75. Stepwise logistic regression was used to simplify the model and assess number of variables needed to reach peak AUC, which included seven selected predictors (insurance, interspaces fused, gender, age, surgical region, CCI, and revision surgery) and had an AUC of 0.74. Model cut-off for predictive PACF discharge was 0.41, yielding a sensitivity of 75% and specificity of 59%.

                    Conclusions

                    The seven variables associated significantly with PACF discharge (age > 60, female gender, non-private insurance, primary operations, instrumented fusion involving 8+ interspaces, thoracolumbar region, and higher CCI scores) may aid in identification of adults at risk for discharge to a PACF following elective multi-level lumbar/thoracolumbar spinal fusions for spinal deformity. This may in turn inform discharge planning and expectation management.
                      Cover page: Development and internal validation of predictive models to assess risk of post-acute care facility discharge in adults undergoing multi-level instrumented fusions for lumbar degenerative pathology and spinal deformity.
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