Impact of Testosterone Recovery on Clinical Outcomes of Patients Treated with Salvage Radiotherapy and Androgen Suppression: A Secondary Analysis of the NRG/RTOG 0534 Sport Phase 3 Trial

PURPOSE/OBJECTIVE(S)

Testosterone (T) kinetics and its relationship with clinical outcomes has not been studied in trials using salvage radiotherapy and androgen deprivation therapy (ADT). We performed a secondary analysis of the NRG Oncology/RTOG 0534 SPPORT trial, which compared prostate bed radiotherapy (PBRT) (arm 1), PBRT + short-term androgen deprivation therapy (ADT) (arm 2), or PBRT + pelvic lymph node radiotherapy (PLNRT) + short-term ADT (arm 3). We assessed longitudinal serum T levels and the impact of testosterone recovery (TR) on clinical outcomes.

MATERIALS/METHODS

ADT was given for 4-6 months in arms 2 and 3, starting 2 months prior to radiotherapy. The trial excluded patients with baseline T < 40% of the lower limit of normal. TR was defined in 3 ways: 1) return to non-castrate level (>50 ng/dL), 2) return to normal level (>300 ng/dL), and 3) return to baseline level. Time to TR was estimated using cumulative incidence and death without an event considered a competing risk. Unadjusted and adjusted hazard ratios and 95% confidence intervals (CIs) were calculated using Cox proportional hazards model. Freedom from progression (FFP) was defined as biochemical failure according to the Phoenix definition (PSA ≥2 ng/mL over the nadir PSA), clinical failure (local, regional, or distant), or death from any cause.

RESULTS

A total of 1699 patients with T at baseline and at least 1 follow-up assessment were included. The median age was 64 years (IQR 59 - 69), 12.8% were black, 14.9% had diabetes, and 54.1% were former or current smokers. Median baseline T in arms 1, 2 and 3 was 320 ng/dL (IQR 239 - 424), 319 ng/dL (IQR 237 - 438) and 330 ng/dL (IQR 252 - 446), respectively. At 6 months, median T in arms 1, 2 and 3 was 290 ng/dL (IQR 210 - 390), 190.4 ng/dL (IQR 66 - 296) and 191 ng/dL (IQR 40.5 - 313). At 2 years, in arms 2 and 3, TR to non-castrate, normal and baseline levels were 95%, 55% and 23%, respectively. At 5 years, in arms 2 and 3, TR to non-castrate, normal and baseline levels were 98%, 73% and 42%, respectively. FFP was superior in arms 2 and 3 vs. arm 1 in patients with TR by all three definitions. In patients with recovered T to normal levels by 2 years (n = 904), the 5-year FFP rates were 71.8% (95% CI 66.9-76.6) in arm 1, 77.2% (72.1-82.2) in arm 2, and 86.3% (82.3-90.3) in arm 3 (arm 2 vs arm 1: HR 0.74, 95% CI 0.56-0.98, p = 0.034; arm 3 vs arm 1: HR 0.54, 95% CI 0.40-0.72, p<.0001).

CONCLUSION

This work represents the largest study of T kinetics in patients treated with salvage radiation and ADT. Approximately half of patients did not normalize their T levels by 2 years. Our data validate an incremental and meaningful FFP benefit of adding short-term ADT and PLNRT to PBRT independent of T recovery.

Role of ATP Binding Cassette Subfamily A Member 1 (ABCA1) in Chemoradiotherapy-induced Renal Injury

PURPOSE/OBJECTIVE(S)

Radiation therapy (RT) alone or combined with chemotherapy reduces cholesterol efflux and causes chronic kidney disease (CKD). There is no treatment for CKD except renal replacement strategies such as dialysis or transplantation. We hypothesize that cancer treatment-induced ABCA1 deficiency leads to dysregulation of cholesterol metabolism, making podocytes susceptible and cancerous cells resistant to treatment-induced injuries.

MATERIALS/METHODS

To quantify the cell index of LNCaP, 786-0, and Podcytes were grown in an e-plate reader (Roche) for 24 h and then were treated with either enzalutamide (10µM) or sunitinib (1.0 µM) or cyclophosphamide (10µM) with or without RT (4Gy) or ABCA1 inducer (liver-X-receptors agonist (GW3965; Sigma; 10µM). Podocyte cholesterol efflux assay was measured using NBD-cholesterol efflux assay, and expression of ABCA1 and cleaved caspase-3 were measured by western blotting. 10-14-week-old C57BL/6 male and female mice were given bilateral kidney X-irradiation of 4Gy with or without cisplatin (3mg/kg; IV). Functional kidney parameters, histopathological changes, and ultrastructural changes were measured at baseline and 20 weeks after treatment. GFR was measured using a FITC-sinistrin-based transdermal monitor.

RESULTS

In vitro studies suggest that after radiation exposure (4Gy and 8Gy), ABCA1 expression decreases in a dose and time-dependent manner in cultured podocytes (p < 0.05), which coincides with reduced cholesterol efflux (p < 0.05) and increased podocyte apoptosis (p < 0.01). In contrast, LXR agonist treatment in vitro prevents reduced ABCA1 expression and cholesterol efflux and prevents podocytes from radiation-induced apoptosis. Our in vitro studies further suggest that Enzalutamide treatment alone reduces the growth of LNCaP and podocytes, and RT (5Gy) plus enzalutamide combination treatment further decreases the growth of LNCaP and podocytes. However, LXR agonist treatment further increased the efficacy of enzalutamide and RT treatment against LNCaP and increased podocyte growth simultaneously. Similarly, Sunitinib with or without RT reduces the growth of renal cancer cells (786-0) and podocytes. LXR agonist treatment further increases the efficacy of the sunitinib and RT against 786-0 cells and simultaneously increases podocyte growth. Cyclophosphamide reduces the growth of the podocytes, and LXR agonist treatment improves the podocyte growth after CP treatment. In vivo studies observed that focal bilateral kidney irradiation with or without cisplatin of C57BL/6 mice induces lipid accumulation in the kidney cortex and increases GBM thickness (p < 0.001), which correlates with decreased Abca1 expression, podocyte number, and GFR.

CONCLUSION

This study shows that LXR agonist treatment protects podocytopathy in vitro and chemotherapy or radiotherapy-induced kidney injury in vivo. ABCA1 may be an important therapeutic target for chemoradiotherapy-induced kidney injuries in cancer patients.

Validation of a Genomic Classifier in the NRG Oncology/RTOG 0521 Phase III Trial of Docetaxel with Androgen Suppression and Radiotherapy for Localized High-Risk Prostate Cancer

PURPOSE/OBJECTIVE(S)

Decipher is a prognostic genomic classifier (GC) validated in several prospective NRG Oncology Phase III trials. Herein, we validate the GC in pre-treatment biopsy samples for risk stratification in a cohort of high-risk men treated with definitive radiotherapy and androgen suppression with or without docetaxel chemotherapy.

MATERIALS/METHODS

As per a pre-specified and approved NCI analysis plan (Navigator #1061), we obtained available formalin-fixed paraffin-embedded tissue from biopsy specimens from the NRG biobank from patients enrolled on the NRG/RTOG 0521 randomized phase III trial. After central review, the highest-grade tumors were profiled on clinical-grade whole-transcriptome arrays (Veracyte, San Diego, CA) and GC scores were obtained. Pre-specified categorical GC scores, adjusted for archival tissue analysis, were used to define higher (>0.46) and lower (≤0.46) risk groups. The primary objective was to validate the independent prognostic ability of GC for metastasis-free survival (MFS) with Cox multivariable analyses (MVA).

RESULTS

Samples were obtained from 283 consented, evaluable patients with tissue (50% of trial) yielding 183 (65%) GC scores that passed quality metrics, 91 from control and 92 from the interventional arm. Median age was 66 years, median PSA was 19.3 ng/uL (IQR: 8.1-41.4), 81% had clinical stage ≥T2 and 80% had Gleason score ≥8 (47% ≥9). Median GC score was 0.55 (IQR: 0.38-0.78) and overall the arms were balanced for key covariates. With a median follow-up of 9.9 years (IQR: 9.3, 10.7), 67 MFS events including 34 distant metastases (DM) were observed. On MVA, only the GC (per 0.1 unit) was independently associated with MFS (HR 1.12, 95% CI 1.01-1.25) as well as DM (sHR 1.22, 95% CI 1.06-1.41), whereas the 4 pre-defined trial risk groups used for stratification (based on Gleason score, T-stage and PSA), randomization and patient age were not. For categorical GC, on MVA, higher-risk GC patients (65%) had worse DM (sHR 2.82, 95% CI 1.1-7.3) compared to those with lower GC. Cumulative incidence of DM at 10-years was 27% for higher GC vs 9% (95% CI 7-18%) for lower GC. No biomarker-by-treatment interaction with GC and the addition of docetaxel was detected.

CONCLUSION

In pre-treatment biopsy samples from a randomized Phase 3 trial cohort, GC demonstrated its ability to further risk stratify clinically high-risk men demonstrating an independent association of GC score with DM and MFS. High-risk prostate cancer is a heterogeneous disease state and GC can improve risk stratification to help personalize shared decision-making. NRG-GU009/PREDICT-RT (NCT04513717) aims to determine the optimal therapy based on GC score for high-risk prostate cancer.

Toxicity Analysis of a Modified Prostate Bed CTV Based on PSMA-PET Patterns of Failure

PURPOSE/OBJECTIVE(S)

After radical prostatectomy (RP), about 20-50% of prostate cancer patients experience biochemical failure, and many can be cured with salvage radiotherapy (sRT). Adding androgen deprivation and pelvic lymph node (PLN) RT to sRT decreases risk of disease progression at the cost of increased toxicity. PSMA PET patterns of local failure after RP show failures outside the RTOG prostate bed CTV (RTOG_CTV) occurring postero-laterally and inferiorly, while in much of the covered bladder local failures are not seen. A modified CTV (m_CTV) encompassing all sites of observed local failures and less of the bladder would potentially reduce dose to the bladder but increase dose to rectum. Herein, we compared sRT plans using RTOG_CTV vs. m_CTV and assessed predicted genitourinary (GU) and gastrointestinal adverse events (AEs).

MATERIALS/METHODS

Volumes for RTOG_CTV, m_CTV, PLN CTV, and OARs were retrospectively contoured on planning CT scans of 28 post-RP patients. Plans were generated for each RTOG_CTV and m_CTV. Doses to prostate bed PTV (CTV + 8mm expansion, 6mm posteriorly) and PLN CTV were 68 Gy and 52.7 Gy, respectively, all in in 34 fractions. Dose-volume histogram (DVH) data for bladder, rectum, and bowel of each plan were extracted. Normal Tissue Complication Probability (NTCP) curves were generated using Lyman-Kutcher-Burman model to predict risk of late G≥3 GU AEs, early GU urgency, leakage, frequency, nocturia, late GI bleed, and late G≥3 GI AEs. Data were compared using 2 sample t-test and Wilcox signed rank test. Correlation of bladder volume and differences in DVH and NTCP data between plans was assessed using Pearson coefficient.

RESULTS

The m_CTV and RTOG_CTV had a median volume of 70.56cc (IQR 59.72-82.17cc) and 132.14cc (IQR 109.33-155.84cc), respectively. Use of m_CTVs resulted in mean absolute decrease of 20.22% and 17.94% in bladder V65 Gy and V40 Gy, respectively (p<0.01 for both), without differences in rectum V65 Gy (p = 0.44), rectum V40 Gy (p = 0.11), or bowel V45 Gy (p = 0.29). Per NTCP curves, m_CTV plans had mean absolute decrease of 24.89% in predicted late G≥3 GU AEs (p<0.01). For predicted early GU AEs, there were mean absolute decreases ranging from 4.85 to 10.21% (p<0.01 for all). Predicted late GI bleed (p = 0.98) and late G≥3 GI AEs (p = 0.99) were not significantly different between plans. When assessed as a continuous variable, smaller bladder volumes had strong correlation with more benefit from m_CTV in bladder V65 Gy (r = -0.71, p<0.01) and moderate correlation with less early GU AEs (r -0.59 to -0.56, p<0.01 for all). There was no correlation with bladder V40 Gy (p = 0.27) or late G≥3 GU AEs (p = 0.14).

CONCLUSION

The m_CTV plans had significantly less dose to the bladder, no increased dose to the rectum and significantly lower predicted rates of early and late GU toxicity. Using a m_CTV encompassing observed local failures from PSMA PET could improve the therapeutic ratio for patients undergoing sRT. Further clinical validation is warranted.

Prognostic Significance of Pretreatment Immune Cell Infiltration in Muscle Invasive Bladder Cancer Treated with Definitive Chemoradiation: Analysis of NRG RTOG 0524 and 0712

PURPOSE/OBJECTIVE(S)

Chemoradiation therapy (CRT) is an organ conserving approach in the treatment of locally advanced bladder cancer. Chemoradiation is thought to potentially result in immunogenic stimulation, and bladder cancer is often a tumor with high immune cell infiltration. Thus, we aimed to profile the tumor immune microenvironment of bladder cancer and identify prognostic immune biomarkers for CRT response by profiling tumor samples from NRG/RTOG 0524 and 0712, two prospective trials of CRT in muscle invasive bladder cancer (MIBC).

MATERIALS/METHODS

Pretreatment tissue samples from both trials were profiled using Cofactor Genomics ImmunoPrism, an RNA sequencing assay that uses gene expression profiles to quantify immune cell populations in the tumor microenvironment (TME). Differential gene expression was estimated for different immune cell type proportions across samples. Kaplan-Meier survival analysis and log rank tests were performed to evaluate differences in overall survival (OS) stratified by genes influenced by immune cell proportions or genes associated with immune response signatures.

RESULTS

A total of 70 samples (43 from RTOG 0524 and 27 from RTOG 0712) underwent analysis using the ImmunoPrism assay. Immune cell proportions were as follows: CD8 T cells: median 1.2%, CD4 T cells: median 0.8%, Treg cells: median 9.2%, CD19 B cells: median 5.1%, M2 macrophages: median 0.8%, M1 macrophages: median 0%. Unbiased clustering based on gene expression profiles driven by immune cell proportions demonstrated two groups: cluster 1 with a low percentage of immune cells and shorter OS (median 31 months) and cluster 2 with a high percentage of immune cells and longer OS (median 101 months, p = 0.036). Higher expression of genes associated with T cell infiltration (CD8A and ICOS) was associated with improved OS (104 vs 35 months, p = 0.028, HR = 0.48 (0.25 - 0.94), p = 0.031) as was higher expression of IDO1, which is associated with the interferon gamma pathway (104 vs 35 months, p = 0.042, HR = 0.49 (0.24 - 0.99), p = 0.046).

CONCLUSION

Bladder tumors have a wide range of immune cell infiltration in the TME. Increased immune cell proportions are prognostic for OS following CRT, as well as a higher expression of genes associated with T cell infiltration interferon gamma signaling. These findings have implications for the integration of immunotherapy in the definitive management of MIBC; and can be explored further in the ongoing NRG/SWOG 1806 trial.

Dose-Volume Parameters to the Urinary Tract Sub-Volumes and Predictors of Genitourinary Acute Toxicity in a Phase 2 Clinical Trial Assessing MRI-Guided Prostate Boost for Localized Prostate Cancer - The Miami BlastM Trial

PURPOSE/OBJECTIVE(S)

The relationship between radiotherapy dose to the sub-volumes of the genitourinary (GU) tract and GU toxicity is poorly understood, particularly in prostate cancer patients treated with an intraprostatic dominant lesion (IDL) boost. While the use of IDL boost improves outcomes, it results in higher doses to GU structures and potentially increased toxicity. We investigated the association between dose-volume histogram (DVH) parameters for urinary tract sub-volumes and GU toxicity in the context of IDL boost in patients enrolled in the Miami BlastM Trial.

MATERIALS/METHODS

DVH data were assessed for patients enrolled in the Miami BlastM, a randomized phase 2 trial (NCT20140627) evaluating upfront versus integrated IDL boost. IDL GTV boost consisted of either 12-14 Gy administered on day 1 or integrated boost of 2.4 Gy per fraction (91.2 Gy total, 98.5 Gy 2.0 Equiv), with the prostate receiving 76 Gy in 38 fractions. Bladder trigone (BTg) and urethra sub-volumes were contoured retrospectively on planning CT scans. GU toxicity was assessed using Common Toxicity Criteria for Adverse Events (CTCAE) version 4 and International Prostate Symptom Score (IPSS). DVHs of the bladder, BTg, bladder minus BTg, prostatic urethra, and bulbomembranous urethra were examined. The primary composite endpoint was CTCAE GU acute toxicity grade (G) ≥2 and/or IPSS increase of ≥10 from baseline. Secondary endpoints were GU acute toxicity G≥2, GU late toxicity G≥2, and IPSS increase of ≥10 from baseline. Univariable and multivariable logistic regression analyses were performed.

RESULTS

A total of 129 patients treated between February 2015 and January 2022 were eligible for analysis. One hundred and one (78%) patients developed either GU acute toxicity G≥2 (68%) and/or an IPSS increase of ≥10 from baseline (30%). Less than 2% of patients developed GU toxicity G≥3. BTg V30 Gy was significantly associated with IPSS increase ≥10 (p = 0.046). The bulbomembranous urethral maximum dose was significantly associated with GU acute toxicity G≥2 and GU late toxicity G≥2 (p <0.05 for both). Average maximum and mean urethral doses were 88.9 and 81.5 Gy, respectively. The BTg maximum dose, V20 Gy, V30 Gy, and V40 Gy were not significantly associated with the primary composite endpoint (p = 0.56, 0.75, 0.89, 0.82, respectively). On multivariable analysis, a higher bulbomembranous urethral maximum dose was significantly associated with GU acute toxicity G≥2 and/or IPSS increase of ≥10 from baseline (p = 0.019).

CONCLUSION

Our data suggest a dose-effect relationship between maximum doses to the bulbomembranous urethra and GU toxicity. A better understanding of RT-related changes to specific sub-volumes of the urethra and strategies to mitigate urethral dose could enhance the therapeutic ratio in prostate cancer patients treated with MRI-guided IDL boost.

Quality of Life Results of Addition of Androgen Deprivation Therapy and Pelvic Lymph Node Treatment to Prostate Bed Salvage Radiotherapy: NRG Oncology/RTOG 0534 SPPORT

PURPOSE/OBJECTIVE(S)

Report the quality of life (QOL) analysis of the SPPORT trial of men with a detectable prostate specific antigen (PSA) after prostatectomy for prostate cancer randomized to (Arm 1) salvage prostate bed radiotherapy (PBRT), (Arm 2) 4-6 months of short-term androgen deprivation therapy (STADT) + PBRT, and (Arm 3) pelvic lymph node radiotherapy (PLNRT) + STADT + PBRT. Primary analysis established a benefit of adding PLNRT and STADT to PBRT. There was higher short term but no statistically significant difference in long term adverse events with the exception of blood or bone marrow events.

MATERIALS/METHODS

QOL endpoints were assessed at baseline, 6 weeks after RT start, 1 and 5 years, including Expanded Prostate Cancer Index Composite (EPIC) (bowel, urinary, sexual, and hormonal domains), Hopkins Symptom Checklist (HSCL-25) (depressive symptoms), and the EuroQol (EQ-5D) (health state weights used in quality adjusted life years (QALYs). In addition to statistical significance, differences in scores were assessed using 0.5 standard deviation (SD) as the criterion for clinical importance. Difference among arms was assessed using pairwise t-tests, Fisher's exact test, and mixed effects regression modeling. To control for multiplicity, the p-value required for statistical significance is p<0.025.

RESULTS

Six hundred forty-four patients consented to QOL, about 210 on each arm. Baseline characteristics were not significantly different among arms: 81% were white and 54% <65 years. For EPIC, bowel domain scores decreased at 6 weeks post-RT then increased by years 1 and 5, although not to baseline levels. One clinically significant difference in bowel scores was Arm 3 vs. Arm 1 at 6 weeks. For the urinary domain, scores decreased at 6 weeks post-RT and remained below baseline at 1 and 5 years, but there were no significant differences among arms. For the sexual domain, there were statistically significant differences between arms at 6 weeks and 1 year with patients receiving STADT exhibiting poorer sexual QOL scores. By year 5 the differences were no longer significant. A similar pattern was seen for the hormonal domain. For HSCL-25, differences at 6 weeks were statistically but not clinically significant, and there were no significant differences at the later time points. Comparisons of QALYs for overall survival over an 8-year horizon showed no significant group differences, with a mean of about 7.8 in each arm. Regarding freedom from progression, QALY means were 5.7, 6.5, and 7.4 years for Arms 1, 2, and 3, respectively, with a significant difference between Arms 3 and 1 (p = <.001) favoring the more intensive treatment.

CONCLUSION

While QOL generally declined among all arms at 6 weeks post RT, there were no clinically significant differences in QOL among arms at 5 years. QALYs for freedom from progression favored STADT + PLNRT + PBRT for salvage treatment of prostate cancer.

Agreement of acute serious events recorded across datasets using linked Australian general practice, hospital, emergency department and death data: implications for research and surveillance

Introduction

Understanding the level of recording of acute serious events in general practice electronic health records (EHRs) is critical for making decisions about the suitability of general practice datasets to address research questions and requirements for linking general practice EHRs with other datasets.

Objectives

To examine data source agreement of five serious acute events (myocardial infarction, stroke, venous thromboembolism (VTE), pancreatitis and suicide) recorded in general practice EHRs compared with hospital, emergency department (ED) and mortality data.

Methods

Data from 61 general practices routinely contributing data to the MedicineInsight database was linked with New South Wales administrative hospital, ED and mortality data. The study population comprised patients with at least three clinical encounters at participating general practices between 2019 and 2020 and at least one record in hospital, ED or mortality data between 2010 and 2020. Agreement was assessed between MedicineInsight diagnostic algorithms for the five events of interest and coded diagnoses in the administrative data. Dates of concordant events were compared.

Results

The study included 274,420 general practice patients with at least one record in the administrative data between 2010 and 2020. Across the five acute events, specificity and NPV were excellent (>98%) but sensitivity (13%-51%) and PPV (30%-75%) were low. Sensitivity and PPV were highest for VTE (50.9%) and acute pancreatitis (75.2%), respectively. The majority (roughly 70-80%) of true positive cases were recorded in the EHR within 30 days of administrative records.

Conclusion

Large proportions of events identified from administrative data were not detected by diagnostic algorithms applied to general practice EHRs within the specific time period. EHR data extraction and study design only partly explain the low sensitivities/PPVs. Our findings support the use of Australian general practice EHRs linked to hospital, ED and mortality data for robust research on the selected serious acute conditions.

Utilisation of pre-exposure prophylaxis (PrEP) for HIV prevention in the Australian general practice setting: a longitudinal observational study

BACKGROUND

Pre-exposure prophylaxis (PrEP) became available through the Australian Pharmaceutical Benefits Scheme (PBS) on 1 April 2018 for HIV infection prevention in patients ≥18years at medium-to-high HIV risk. The aims were to investigate PrEP utilisation in general practice since PBS listing, and factors associated with discontinuation.

METHODS

This longitudinal study included patients aged 18-74years attending general practices participating in MedicineInsight, a large-scale national primary care database of deidentified electronic health records, between October 2017 and September 2019.

RESULTS

PrEP utilisation increased 10-fold following PBS listing. On average, patients had 9.7 PrEP prescriptions per year; a medication possession ratio of 80.8%. Of 1552 patients prescribed PrEP from April 2018, most were male (98.3%), aged 18-39years (59.3%), resided in major cities (86.7%) and in the two most socioeconomically advantaged quintiles (70.0%). Almost half (49.1%) of the patients were identified as new to PrEP. At study end, 65.1% were on active PrEP (16.5%, of whom had non-continuous use), 19.2% had discontinued PrEP and 15.7% were lost to follow up. Patients who discontinued were more likely to attend low rather than high PrEP caseload practices (adjusted odds ratio [aOR] 1.7; 95% CI: 1.0-2.8; P=0.047). The odds of non-continuous therapy was 2.9-fold higher in patients with bipolar disorder (aOR 2.89; 95% CI: 1.10-7.6; P=0.045).

CONCLUSIONS

Following PBS listing, PrEP utilisation increased and stopping therapy was associated with attending low caseload practices. General practice education, particularly among low caseload practices, could help address these disparities.

Characteristics of patients aged 50-74 years with a request for an immunochemical faecal occult blood test in the Australian general practice setting

ObjectiveTo support improving participation in the National Bowel Cancer Screening Program (NBCSP), we aimed to identify Medicare-subsidised test requests for immunochemical faecal occult blood tests (FOBT) in Australian general practice for patients aged 50-74 years, eligible for the NBCSP, and describe sociodemographics, risk factors, indications and outcomes.MethodsA cross-sectional study was conducted using de-identified data from 441 Australian general practice sites in the MedicineInsight database, recorded from 1 January 2018 to 31 December 2019.ResultsOf the 683 625 eligible patients, 45 771 (6.7%) had a record of a general practitioner (GP)-requested FOBT, either to aid diagnosis in symptomatic patients, or for screening; 144 986 (21.2%) patients had only an NBCSP FOBT. A diagnosis of polyps, gastrointestinal inflammatory condition or haemorrhoids, or a referral to a gastroenterologist or general surgeon, was more commonly recorded in the 6 months after a GP-requested FOBT than after an NBCSP FOBT. Uptake of NBCSP FOBTs was lower among those with obesity, high alcohol consumption and current smokers, who are at higher risk of bowel cancer.ConclusionsThis study describes the patient characteristics, reasons and outcomes associated with GP-requested FOBTs, identifies under-screened population sub-groups, and suggests involvement of GPs to improve participation in the NBCSP.

Patterns of real-world opioid prescribing in Australian general practice (2013-18)

Little is known about private-market opioid prescribing and how Australian opioid policies impact prescribing across public and private markets in Australia. We aimed to investigate publicly subsidised and private-market opioid prescribing from 2013 to 2018. We used prescribing records from MedicineInsight, an Australian primary care database, to examine trends in prescriptions for non-injectable opioid formulations from October 2013 to September 2018. We examined annual opioid prescribing trends overall, by opioid agent, and by market (public and private). We further examined patterns of fentanyl patch prescribing focusing on co-prescribed medicines and use in opioid-naïve patients. Opioids accounted for 8% of all prescriptions over the study period and 468 893 patients were prescribed at least one opioid of interest. Prescribing rates for oxycodone/naloxone and tapentadol increased, whereas those for fentanyl patches, morphine and single-agent oxycodone decreased over the study period. Private-market prescribing rates of codeine (schedule 4) increased notably following its up-scheduling to prescription-only status. Among patients prescribed fentanyl patches, 29% were potentially opioid-naïve and 49% were prescribed another opioid on the same day. The private-medicines market is a small but growing component of opioid use in Australia and one way in which prescribers and patients can avoid access restrictions in the public market for these medicines. Although fentanyl patch prescribing declined, there is room for improvement in prescribing fentanyl patches among opioid-naïve patients, and co-prescribing of fentanyl patches with other sedatives.

763Validity of algorithms for identifying five chronic conditions in MedicineInsight, Australian national primary care data

Background

MedicineInsight is a database containing de-identified electronic health records (EHRs) from over 700 Australian general practices. To support the trust placed in analyses of MedicineInsight data, additional evidence regarding the accuracy of the data is needed.

Methods

This study measures the validity of algorithms available in MedicineInsight that identify patients with depression, anxiety, asthma, type 2 diabetes and osteoporosis. Fifty practices met eligibility criteria regarding patient load and location, five were randomly selected and four agreed to participate. Within each practice, 250 patients aged ≥ 40 years were randomly selected. This age restriction increased the prevalence of the evaluated conditions, thereby optimising statistical power. Trained staff review the full EHR for these patients, including progress notes and correspondence, which are not available in MedicineInsight because they may contain identifiable information.

Results

With data collection almost complete, the target sample size will not be attainable. Power calculations indicate the current sample of 479 should provide adequate precision. For each condition of interest, the sensitivity, specificity, positive predictive value and negative predictive value of the algorithm is calculated. The full EHR review is the gold standard against which the algorithms are benchmarked.

Conclusions

The findings will indicate whether these algorithms demonstrate adequate accuracy to be used for research and decision-making.

Key messages

This additional understanding regarding the accuracy of MedicineInsight data will facilitate the interpretation of analyses of MedicineInsight data and guide improvements to the algorithms.

Breathlessness and opioid prescribing in COPD in general practice: a cross-sectional, observational study

Chronic breathlessness is a disabling syndrome, prevalent in people with advanced chronic obstructive pulmonary disease (COPD). Regular, low-dose, oral sustained-release morphine is approved in Australia to reduce symptomatic chronic breathlessness. We aimed to determine the current prescribing patterns of opioids for chronic breathlessness in COPD in Australian general practice and to define any associated patient and practitioner characteristics. Five years (2011 to 2016) of the Bettering the Evaluation and Care of Health database, an Australian national, continual, cross-sectional study of clinical care in general practice were used. The database included 100 consecutive clinical encounters from almost 1000 general practitioners annually (n=488 100 encounters). Descriptive analyses with subsequent regression models were generated. Breathlessness as a patient-defined reason for encounter was identified in 621 of 4522 encounters where COPD was managed. Opioids were prescribed in 309 of 4522 encounters where COPD was managed (6.8%; (95% CI) 6.1-7.6), of which only 17 were prescribed for breathlessness, and the rest for other conditions almost entirely related to pain. Patient age (45-64 years versus age 80+ years, OR 1.68; 1.19-2.36), Commonwealth Concession Card holders (OR 1.70; 1.23-2.34) and socioeconomic disadvantage (OR 1.30; 1.01-1.68) were associated with increased likelihood of opioid prescription at COPD encounters. The rate of opioid prescriptions rose over the 5 years of study. In primary care encounters for COPD, opioids were prescribed in 6.8% of cases, but almost never for breathlessness. These data create a baseline against which to compare changes in prescribing as the treatment of chronic breathlessness evolves.

Prevalence, incidence and management of atopic dermatitis in Australian general practice using routinely collected data from MedicineInsight

Background/Objectives

The prevalence of atopic dermatitis (AD) has increased significantly in industrialised countries in recent decades but data about the incidence or prevalence of AD in Australia are sparse. We aimed to determine the prevalence and incidence of AD among patients seen in Australian general practice and the use of specified medicines.

Methods

This was a cross‐sectional study of 2.1 million patients attending 494 general practices in the MedicineInsight program from 1 January 2017 to 31 December 2018. We assessed the prevalence (lifetime and current), incidence, management and severity of AD.

Results

The lifetime (ever diagnosed) prevalence of AD in this general practice population was 16.4% and was greater in females (17.3%) than males (15.3%). One in five patients with AD were classified as having moderate‐to‐severe disease. Prevalence over the last two years was 6.3%. The incidence of AD in 2018 was 2.0% and was greater in females (2.2%) and for patients aged 0–4 years (3.9%). Patients with AD had an increased risk of insomnia, anxiety and depression, compared to those with no recorded AD. For AD patients, topical corticosteroids were the most commonly prescribed AD medication (36.5%) and topical calcineurin inhibitors the least (0.1%), with systemic corticosteroids (15.6%) more commonly prescribed than other immunosuppressants (0.9%).

Conclusions

Our findings provide important insights into the epidemiology of AD and its management in Australian general practice. This information is likely to be useful in planning effective interventions to support GPs in the optimal management of patients with AD.

Osteoporosis management in Australian general practice: an analysis of current osteoporosis treatment patterns and gaps in practice

Background

Among Australians aged 50 and over, an estimated 1 in 4 men and 2 in 5 women will experience a minimal trauma fracture during their remaining lifetime. Effective fracture prevention is hindered by substantial undertreatment, even of patients who clearly warrant pharmacological therapy. Poor adherence to osteoporosis treatment is also a leading cause of repeat fractures and hospitalisation. The aim of this study was to identify current osteoporosis treatment patterns and gaps in practice in Australia, using general practice data, and to explore general practitioners’ (GPs’) attitudes to osteoporosis treatment and their views on patient factors affecting osteoporosis management.

Methods

The study was conducted in two phases. Phase 1 was a longitudinal retrospective cohort study which utilised data from MedicineInsight – a national general practice data program that extracts longitudinal, de-identified patient data from clinical information systems (CISs) of participating general practices. Phase 2 included semi-structured, in-depth telephone interviews with a sample of MedicineInsight practice GPs. Data were analysed using an inductive thematic analysis method informed by the theory of planned behaviour.

Results

A diagnosis of osteoporosis was recorded in 12.4% of patients over the age of 50 years seen in general practice. Of those diagnosed with osteoporosis, almost a quarter were not prescribed osteoporosis medicines. From 2012 to 17, there was a progressive increase in the number of denosumab prescriptions, while prescriptions for bisphosphonates and other osteoporosis medicines decreased. More than 80% of patients who ceased denosumab treatment had no subsequent bisphosphonate prescription recorded. Interviews with GPs revealed beliefs and attitudes that may have influenced their intentions towards prescribing and osteoporosis management.

Conclusions

This study suggests that within the Australian general practice setting, osteoporosis is underdiagnosed and undertreated. In addition, it appears that most patients who ceased denosumab treatment had no record of subsequent antiresorptive therapy, which would place them at risk of further fractures. The study supports the need for the development of clinical education programs addressing GP knowledge gaps and attitudes, and the implementation of specific interventions such as good reminder/recall systems to avoid delays in reviewing and treating patients with osteoporosis.

Abstract 4183: Recruiting African-American prostate cancer patients for biobank research

Significant racial disparities exist in prostate cancer (PCa) incidence and mortality rates. Exploration of the basis for disparities would be enhanced by access to data and biological specimens on men of African Ancestry (AA). Unfortunately, AA men remain underrepresented in cancer biorepositories. To address this gap, we have embarked on an effort to create a state-wide biospecimen bank focused on AA men with PCa in Florida. The objective is to collect and manage patients’ data, outcome information, and biospecimens (i.e., tumor tissue samples and saliva) from diverse AA men for research. The objective is to collect and manage patients’ data, outcome information, and biospecimens who have been diagnosed with PCa in Florida. Self-identified AA PCa patients, diagnosed between 2013 and 2017, who were living in Florida at the time of diagnosis were identified through the Florida State cancer registry. Potential participants were mailed packets describing the study, with follow-up by telephone to answer questions and obtain informed consent. Interested patients were screened for eligibility and asked to complete a questionnaire, provide a saliva sample, and provide permission to obtain their tumor tissue sample. Patients were offered up to $30 for participating in the study. The Florida Cancer Registry reported a total of 7,960 AA PCa cases during the ascertainment period. Information packets were sent to 4,898 AA. A total of 116 were found to be ineligible mainly due to deceased or non-English speaking patients. To date, 796 have consented to participate, 1,175 declined ether by mail (n=185) or phone (=985), 740 could not be located, and 2,033 have not responded to the initial information packet/phone after total of 5 attempts. This yields a participation rate of 16.3% (796/4,898). The adjusted participation rate, or the percentage of participants who consented to participate out of those who had communication with the research team, is 41% (796/1,959). Primary reasons for declining include patients stating that they are not interested (72%), too sick (8%), or too busy (5%). A significant inverse association was found between current age and participation rate (p&lt;0.0001) but not insurance status. Older AA PCa patients were found to be less likely to participate in the study. A significant association was also found between Gleason score and participation rate. AA men who had a more aggressive form of PCa (higher Gleason score) were more likely to participate in the study (p&lt;0.01). Our results demonstrate that recruiting Blacks/African-American PCa patients in the biobank study using a cancer registry is feasible, yet difficult. Despite prevailing recruitment challenges, we implemented a diverse of recruitment methods to increase reach. These recruitment methods helped identify additional avenues for targeting this population to increase participation and, ultimately, address cancer disparities among this population.

Citation Format: Jennifer Damonte, Siddhartha Roy, Carmen Benson, Kala Jamison, Hyun Park, Allan Pollack, Shahla Masood, Changdong Yeo, Young-chul Kim, Jasreman Dhillon, Kosj Yamoah, Julio Pow-Sang, Thomas A. Sellers, Clement K. Gwede, Jong Y. Park. Recruiting African-American prostate cancer patients for biobank research [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4183.

Problems managed and medications prescribed during encounters with people with autism spectrum disorder in Australian general practice

Autism spectrum disorder is associated with high rates of co-occurring health conditions. While elevated prescription rates of psychotropic medications have been reported in the United Kingdom and the United States, there is a paucity of research investigating clinical and prescribing practices in Australia. This study describes the problems managed and medications prescribed by general practitioners in Australia during encounters where an autism spectrum disorder was recorded. Information was collected from 2000 to 2014 as part of the Bettering the Evaluation and Care of Health programme. Encounters where patients were aged less than 25 years and autism spectrum disorder was recorded as one of the reasons for encounter and/or problems managed ( n = 579) were compared to all other Bettering the Evaluation and Care of Health programme encounters with patients aged less than 25 years ( n = 281,473). At 'autism spectrum disorder' encounters, there was a significantly higher management rate of psychological problems, and significantly lower management rates of skin, respiratory and general/unspecified problems, than at 'non-autism spectrum disorder' encounters. The rate of psychological medication prescription was significantly higher at 'autism spectrum disorder' encounters than at 'non-autism spectrum disorder' encounters. The most common medications prescribed at 'autism spectrum disorder' encounters were antipsychotics and antidepressants. Primary healthcare providers need adequate support and training to identify and manage physical and mental health concerns among individuals with autism spectrum disorder.

Management of vertebral compression fracture in general practice: BEACH program

Importance

The pain associated with vertebral compression fractures can cause significant loss of function and quality of life for older adults. Despite this, there is little consensus on how best to manage this condition.

Objective

To describe usual care provided by general practitioners (GPs) in Australia for the management of vertebral compression fractures.

Design, setting and participants

Data from the Bettering the Evaluation And Care of Health (BEACH) program collected between April 2005 and March 2015 was used for this study. Each year, a random sample of approximately 1,000 GPs each recorded information on 100 consecutive encounters. We selected those encounters at which vertebral compression fracture was managed. Analyses of management options were limited to encounters with patients aged 50 years or over.

Main outcome(s) and measure(s)

i) patient demographics; ii) diagnoses/problems managed; iii) the management provided for vertebral compression fracture during the encounter. Robust 95% confidence intervals, adjusted for the cluster survey design, were used to assess significant differences between group means.

Results

Vertebral compression fractures were managed in 211 (0.022%; 95% CI: 0.018–0.025) of the 977,300 BEACH encounters recorded April 2005– March 2015. That provides a national annual estimate of 26,000 (95% CI: 22,000–29,000) encounters at which vertebral fractures were managed. At encounters with patients aged 50 years or over (those at higher risk of primary osteoporosis), prescription of analgesics was the most common management action, particularly opioids analgesics (47.1 per 100 vertebral fractures; 95% CI: 38.4–55.7). Prescriptions of paracetamol (8.2; 95% CI: 4–12.4) or non-steroidal anti-inflammatory drugs (4.1; 95% CI: 1.1–7.1) were less frequent. Non-pharmacological treatment was provided at a rate of 22.4 per 100 vertebral fractures (95% CI: 14.6–30.1). At least one referral (to hospital, specialist, allied health care or other) was given for 12.3 per 100 vertebral fractures (95% CI: 7.8–16.8).

Conclusions and relevance

The prescription of oral opioid analgesics remains the common general practice approach for vertebral compression fractures management, despite the lack of evidence to support this. Clinical trials addressing management of these fractures are urgently needed to improve the quality of care patients receive.

Primary health care for people with an intellectual disability: an exploration of consultations, problems identified, and their management in Australia

BACKGROUND

People with an intellectual disability (ID) have more complex and different patterns of health care needs than the general population. They experience a greater burden of multi-morbidity, high levels of undetected and unmanaged health issues, and premature mortality than the general population. Primary care has a key role in the health care of people with an ID. Currently, very little is known about the consultation type and length, problems managed, and how general practitioners (GPs) manage these problems for people with an ID compared with the general population. This information would provide valuable insights into how GPs are achieving the health guidelines and facilitating people with an ID to achieve the highest attainable standard of health.

METHODS

A secondary analysis of data was collected from January 2003 to December 2012 from the Bettering the Evaluation and Care of Health (BEACH) programme. Consultation type, consultation length in minutes, problem(s) managed during the consultation, medications, treatments provided, and referrals made, pre and post age-sex standardisation, at all GP encounters with people identified in the encounter record as having an ID ('ID' encounters, n = 690) were compared with those at 'non-ID' encounters (n = 970 641). Statistical significance was tested with 95% confidence intervals.

RESULTS

This study identified significant differences in consultation types, consultation length, problem(s) managed during the consultation, medications, treatments provided, and referrals made at 'ID' encounters compared with 'non-ID' encounters. 'ID' encounters had more indirect encounters, longer consultations, more problems managed, but an under management of common health conditions in people with an ID. Administrative rather than medically related actions dominated clinical treatments for people at 'ID' encounters, and they received fewer procedural treatments, referrals to specialists, and medications compared with those at 'non-ID' encounters.

CONCLUSION

The significant differences in consultations, problems identified and managed suggest that GPs may require additional support to (1) identify and manage common medical conditions experienced by people with an ID; (2) manage the increased time required for consultations; and (3) directly consult with people with an ID. Further research is required to determine why GPs managed problems in a significantly different way for people with an ID.

Aflibercept as a Second Line Therapy for Neovascular Age Related Macular Degeneration in Israel (ASLI) study

PurposeThe purpose of this study is to evaluate an early switch to aflibecept in eyes with neovascular age-related macular degeneration (nvAMD) showing partial or lack of response for initial therapy with bevacizumab.MethodsThe Aflibercept as a Second Line Therapy for Neovascular Age Related Macular Degeneration in Israel (ASLI) was a prospective, multicenter, single-arm clinical trial. Eyes with nvAMD having incomplete response to 3-9 prior bevacizumab injections were recruited. Three monthly intravitreal aflibercept (2 mg) injections were administered, followed by two bi-monthly injections and a final examination at week 28. An optional injection was allowed at week 20.ResultsForty-seven eyes of 46 patients (mean±SD age 76±8 years) were recruited. The mean number of prior bevacizumab injections was 5.5±2.9. The mean visual acuity improved from 60.3±10 ETDRS letters at baseline to 63.1±15 letters at week 28 (P=0.02, paired t-test). The central subfield thickness (CST) reduced from 409±127 micron at baseline to 330±110 microns at week 4 (P=0.0002; paired t-test), and 277±70 microns at week 28 (P=0.00002; paired t-test). Twenty-two eyes had three to five prior bevacizumab injections (mean 5.1±0.7), and 25 eyes had six to nine prior injections (7.32±1.2). Both groups had reduced CST from baseline to week 28 (P=0.0004 and P=0.0007; paired t-test, respectively). Thirty-five (75%) eyes required the optional additional aflibercept injection at week 20.ConclusionsThe ASLI study demonstrated improved BCVA and reduced CST following an early switch to aflibercept therapy in eyes with prior incomplete response to initial therapy with three to nine bevacizumab injections.

Primary health care for people with an intellectual disability: an exploration of demographic characteristics and reasons for encounters from the BEACH programme

BACKGROUND

People with an intellectual disability (ID) have complex and different patterns of healthcare needs. Poor participation in primary health care contributes to the high levels of undetected and unmanaged health issues and premature deaths of people with an ID. Limited research is available on the characteristics of people with an ID, their reasons for consulting general practitioners (GPs), and if these differ to people without an ID. Gaining such insights may provide an avenue to better understand patterns of primary care use and potential gaps in usage by people with an ID given their complex health profile compared with people without an ID.

METHOD

A secondary analysis of data collected January 2003 to December 2012 from The Bettering the Evaluation and Care of Health programme was used. Participant characteristics and their reasons for encounter, pre- and post-age-sex standardisation, at all GP encounters with people identified in the encounter record as having an ID ('ID' encounters, n = 690) were compared with those at 'non-ID' encounters (n = 970 641). Statistical significance was tested with chi-squared statistics or 95% confidence intervals as appropriate.

RESULTS

This study identified significant differences in participant characteristics and their reasons for consulting GPs at ID encounters compared with non-ID encounters. Participants at ID encounters had a skewed demography, an over-representation of presentations for psychological, social and 'general and unspecified' reasons, and an under-representation of presentations for core physical health and preventive health measures. Administrative rather than medically related reasons dominated presentations to general practice at ID encounters.

CONCLUSION

There are significant differences in the characteristics of participants and their reasons for presentation to general practice in Australia for participants at ID encounters compared with non-ID encounters. This work suggests that there is a difference in service use patterns between these two groups. These findings may suggest that people with an ID experience barriers to participating in essential primary healthcare services.