Validated machine learning tools to distinguish immune checkpoint inhibitor, radiotherapy, COVID-19 and other infective pneumonitis.

BACKGROUND: Pneumonitis is a well-described, potentially disabling, or fatal adverse effect associated with both immune checkpoint inhibitors (ICI) and thoracic radiotherapy. Accurate differentiation between checkpoint inhibitor pneumonitis (CIP) radiation pneumonitis (RP), and infective pneumonitis (IP) is crucial for swift, appropriate, and tailored management to achieve optimal patient outcomes. However, correct diagnosis is often challenging, owing to overlapping clinical presentations and radiological patterns. METHODS: In this multi-centre study of 455 patients, we used machine learning with radiomic features extracted from chest CT imaging to develop and validate five models to distinguish CIP and RP from COVID-19, non-COVID-19 infective pneumonitis, and each other. Model performance was compared to that of two radiologists. RESULTS: Models to distinguish RP from COVID-19, CIP from COVID-19 and CIP from non-COVID-19 IP out-performed radiologists (test set AUCs of 0.92 vs 0.8 and 0.8; 0.68 vs 0.43 and 0.4; 0.71 vs 0.55 and 0.63 respectively). Models to distinguish RP from non-COVID-19 IP and CIP from RP were not superior to radiologists but demonstrated modest performance, with test set AUCs of 0.81 and 0.8 respectively. The CIP vs RP model performed less well on patients with prior exposure to both ICI and radiotherapy (AUC 0.54), though the radiologists also had difficulty distinguishing this test cohort (AUC values 0.6 and 0.6). CONCLUSION: Our results demonstrate the potential utility of such tools as a second or concurrent reader to support oncologists, radiologists, and chest physicians in cases of diagnostic uncertainty. Further research is required for patients with exposure to both ICI and thoracic radiotherapy.

Gross tumour volume radiomics for prognostication of recurrence & death following radical radiotherapy for NSCLC.

Recurrence occurs in up to 36% of patients treated with curative-intent radiotherapy for NSCLC. Identifying patients at higher risk of recurrence for more intensive surveillance may facilitate the earlier introduction of the next line of treatment. We aimed to use radiotherapy planning CT scans to develop radiomic classification models that predict overall survival (OS), recurrence-free survival (RFS) and recurrence two years post-treatment for risk-stratification. A retrospective multi-centre study of >900 patients receiving curative-intent radiotherapy for stage I-III NSCLC was undertaken. Models using radiomic and/or clinical features were developed, compared with 10-fold cross-validation and an external test set, and benchmarked against TNM-stage. Respective validation and test set AUCs (with 95% confidence intervals) for the radiomic-only models were: (1) OS: 0.712 (0.592-0.832) and 0.685 (0.585-0.784), (2) RFS: 0.825 (0.733-0.916) and 0.750 (0.665-0.835), (3) Recurrence: 0.678 (0.554-0.801) and 0.673 (0.577-0.77). For the combined models: (1) OS: 0.702 (0.583-0.822) and 0.683 (0.586-0.78), (2) RFS: 0.805 (0.707-0.903) and 0·755 (0.672-0.838), (3) Recurrence: 0·637 (0.51-0.·765) and 0·738 (0.649-0.826). Kaplan-Meier analyses demonstrate OS and RFS difference of >300 and >400 days respectively between low and high-risk groups. We have developed validated and externally tested radiomic-based prediction models. Such models could be integrated into the routine radiotherapy workflow, thus informing a personalised surveillance strategy at the point of treatment. Our work lays the foundations for future prospective clinical trials for quantitative personalised risk-stratification for surveillance following curative-intent radiotherapy for NSCLC.

A comparison of machine learning methods for predicting recurrence and death after curative-intent radiotherapy for non-small cell lung cancer: Development and validation of multivariable clinical prediction models.

BACKGROUND: Surveillance is universally recommended for non-small cell lung cancer (NSCLC) patients treated with curative-intent radiotherapy. High-quality evidence to inform optimal surveillance strategies is lacking. Machine learning demonstrates promise in accurate outcome prediction for a variety of health conditions. The purpose of this study was to utilise readily available patient, tumour, and treatment data to develop, validate and externally test machine learning models for predicting recurrence, recurrence-free survival (RFS) and overall survival (OS) at 2 years from treatment. METHODS: A retrospective, multicentre study of patients receiving curative-intent radiotherapy for NSCLC was undertaken. A total of 657 patients from 5 hospitals were eligible for inclusion. Data pre-processing derived 34 features for predictive modelling. Combinations of 8 feature reduction methods and 10 machine learning classification algorithms were compared, producing risk-stratification models for predicting recurrence, RFS and OS. Models were compared with 10-fold cross validation and an external test set and benchmarked against TNM-stage and performance status. Youden Index was derived from validation set ROC curves to distinguish high and low risk groups and Kaplan-Meier analyses performed. FINDINGS: Median follow-up time was 852 days. Parameters were well matched across training-validation and external test sets: Mean age was 73 and 71 respectively, and recurrence, RFS and OS rates at 2 years were 43% vs 34%, 54% vs 47% and 54% vs 47% respectively. The respective validation and test set AUCs were as follows: 1) RFS: 0·682 (0·575-0·788) and 0·681 (0·597-0·766), 2) Recurrence: 0·687 (0·582-0·793) and 0·722 (0·635-0·81), and 3) OS: 0·759 (0·663-0·855) and 0·717 (0·634-0·8). Our models were superior to TNM stage and performance status in predicting recurrence and OS. INTERPRETATION: This robust and ready to use machine learning method, validated and externally tested, sets the stage for future clinical trials entailing quantitative personalised risk-stratification and surveillance following curative-intent radiotherapy for NSCLC. FUNDING: A full list of funding bodies that contributed to this study can be found in the Acknowledgements section.

Immune Checkpoint Inhibitor and Radiotherapy-Related Pneumonitis: An Informatics Approach to Determine Real-World Incidence, Severity, Management, and Resource Implications.

Pneumonitis is a well-described, potentially life-threatening adverse effect of immune checkpoint inhibitors (ICI) and thoracic radiotherapy. It can require additional investigations, treatment, and interruption of cancer therapy. It is important for clinicians to have an awareness of its incidence and severity, however real-world data are lacking and do not always correlate with findings from clinical trials. Similarly, there is a dearth of information on cost impact of symptomatic pneumonitis. Informatics approaches are increasingly being applied to healthcare data for their ability to identify specific patient cohorts efficiently, at scale. We developed a Structured Query Language (SQL)-based informatics algorithm which we applied to CT report text to identify cases of ICI and radiotherapy pneumonitis between 1/1/2015 and 31/12/2020. Further data on severity, investigations, medical management were also acquired from the electronic health record. We identified 248 cases of pneumonitis attributable to ICI and/or radiotherapy, of which 139 were symptomatic with CTCAE severity grade 2 or more. The grade ≥2 ICI pneumonitis incidence in our cohort is 5.43%, greater than the all-grade 1.3-2.7% incidence reported in the literature. Time to onset of ICI pneumonitis was also longer in our cohort (mean 4.5 months, range 4 days-21 months), compared to the median 2.7 months (range 9 days-19.2 months) described in the literature. The estimated average healthcare cost of symptomatic pneumonitis is £3932.33 per patient. In this study we use an informatics approach to present new real-world data on the incidence, severity, management, and resource burden of ICI and radiotherapy pneumonitis. To our knowledge, this is the first study to look at real-world incidence and healthcare resource utilisation at the per-patient level in a UK cancer hospital. Improved management of pneumonitis may facilitate prompt continuation of cancer therapy, and improved outcomes for this not insubstantial cohort of patients.

Real-world outcomes in thoracic cancer patients with severe Acute respiratory syndrome Coronavirus 2 (COVID-19): Single UK institution experience.

BACKGROUND: UK COVID-19 mortality rates are amongst the highest globally. Controversy exists on the vulnerability of thoracic cancer patients. We describe the characteristics and sequelae of patients with thoracic cancer treated at a UK cancer centre infected with COVID-19. METHODS: Patients undergoing care for thoracic cancer diagnosed with COVID-19 (RT-PCR/radiology/clinically) between March-June 2020 were included. Data were extracted from patient records. RESULTS: Thirty-two patients were included: 14 (43%) diagnosed by RT-PCR, 18 (57%) by radiology and/or convincing symptoms. 88% had advanced thoracic malignancies. Eleven of 14 (79%) patients diagnosed by RT-PCR and 12 of 18 (56%) patients diagnosed by radiology/clinically were hospitalised, of which four (29%) and 2 (11%) patients required high-dependency/intensive care respectively. Three (21%) patients diagnosed by RT-PCR and 2 (11%) patients diagnosed by radiology/clinically required non-invasive ventilation; none were intubated. Complications included pneumonia and sepsis (43% and 14% respectively in patients diagnosed by RT-PCR; 17% and 11% respectively in patients diagnosed by radiology/clinically). In patients receiving active cancer treatment, therapy was delayed/ceased in 10/12 (83%) and 7/11 (64%) patients diagnosed by RT-PCR and radiology/clinically respectively. Nine (28%) patients died; all were smokers. Median time from symptom onset to death was 7 days (range 3-37). CONCLUSIONS: The immediate morbidity from COVID-19 is high in thoracic cancer patients. Hospitalisation and treatment interruption rates were high. Improved risk-stratification models for UK cancer patients are urgently needed to guide safe cancer-care delivery without compromising efficacy.

Intratumoral Hydrogen Peroxide With Radiation Therapy in Locally Advanced Breast Cancer: Results From a Phase 1 Clinical Trial.

PURPOSE: Hydrogen peroxide (H2O2) plays a vital role in normal cellular processes but at supraphysiological concentrations causes oxidative stress and cytotoxicity, a property that is potentially exploitable for the treatment of cancer in combination with radiation therapy (RT). We report the first phase 1 trial testing the safety and tolerability of intratumoral H2O2 + external beam RT as a novel combination in patients with breast cancer and exploratory plasma marker analyses investigating possible mechanisms of action. METHODS AND MATERIALS: Twelve patients with breast tumors ≥3 cm (surgically or medically inoperable) received intratumoral H2O2 with either 36 Gy in 6 twice-weekly fractions (n = 6) or 49.5 Gy in 18 daily fractions (n = 6) to the whole breast ± locoregional lymph nodes in a single-center, nonrandomized study. H2O2 was mixed in 1% sodium hyaluronate gel (final H2O2 concentration 0.5%) before administration to slow drug release and minimize local discomfort. The mixture was injected intratumorally under ultrasound guidance twice weekly 1 hour before RT. The primary endpoint was patient-reported maximum intratumoral pain intensity before and 24 hours postinjection. Secondary endpoints included grade ≥3 skin toxicity and tumor response by ultrasound. Blood samples were collected before, during, and at the end of treatment for cell-death and immune marker analysis. RESULTS: Compliance with H2O2 and RT was 100%. Five of 12 patients reported moderate pain after injection (grade 2 Common Terminology Criteria for Adverse Events v4.02) with median duration 60 minutes (interquartile range, 20-120 minutes). Skin toxicity was comparable to RT alone, with maintained partial/complete tumor response relative to baseline in 11 of 12 patients at last follow-up (median 12 months). Blood marker analysis highlighted significant associations of TRAIL, IL-1ß, IL-4, and MIP-1α with tumor response. CONCLUSIONS: Intratumoral H2O2 with RT is well tolerated with no additional toxicity compared with RT alone. If efficacy is confirmed in a randomized phase 2 trial, the approach has potential as a cost-effective radiation response enhancer in multiple cancer types in which locoregional control after RT alone remains poor.

Systemic treatment of brain metastases in non-small cell lung cancer.

Brain metastases (BrMs) are associated with significant morbidity and are found in up to 50% of patients with advanced non-small cell lung cancer (NSCLC). Most of the literature focuses on symptomatic BrMs, with a lack of baseline brain imaging in asymptomatic patients. Unfortunately, much of the data on local treatments with or without systemic treatment is retrospective. Clinical trials of systemic treatments largely exclude patients with BrMs. Chemotherapy is an active treatment for BrM with response rates in the brain similar to other sites of disease. Targeted systemic treatments in patients with driver mutations (EGFR and ALK-MET to date) have impressive central nervous system (CNS) penetrance and response rates. Unfortunately, no prospective data can currently guide the timings or modality of local therapies with systemic treatments in these patients who have a high incidence of CNS disease, but retrospective data suggest that early local therapies may give better intracranial progression-free survival (ICPFS). Recent immunotherapy trials have included patients with BrMs. These patients have largely been pre-treated with local therapies and are asymptomatic. Thus, the current standard is becoming, early local therapies before or in conjunction with immunotherapy agents. The approach seems to be safe. Prospective studies are needed in NSCLC BrMs patients to make sure any benefit from local therapies on the ICPFS and quality of life is not overlooked. Here we report what we think are reasonable conclusions from the available data and make suggestions for future clinical trials in the management of NSCLC BrMs.

18F-Fludeoxyglucose PET/CT in SCLC: Analysis of the CONVERT Randomized Controlled Trial.

INTRODUCTION: We used phase-3 CONVERT trial data to investigate the impact of fludeoxyglucose F 18 (18F-FDG) positron emission tomography (PET)/computed tomography (CT) in SCLC. METHODS: CONVERT randomized patients with limited-stage SCLC to twice-daily (45 Gy in 30 fractions) or once-daily (66 Gy in 33 fractions) chemoradiotherapy. Patients were divided into two groups in this unplanned analysis: those staged with conventional imaging (contrast-enhanced thorax and abdomen CT and brain imaging with or without bone scintigraphy) and those staged with 18F-FDG PET/CT in addition. RESULTS: Data on a total of 540 patients were analyzed. Compared with patients who underwent conventional imaging (n = 231), patients also staged with 18F-FDG PET/CT (n = 309) had a smaller gross tumor volume (p = 0.003), were less likely to have an increased pretreatment serum lactate dehydrogenase level (p = 0.035), and received more chemotherapy (p = 0.026). There were no significant differences in overall (hazard ratio = 0.87, 95% confidence interval: 0.70-1.08, p = 0.192) and progression-free survival (hazard ratio = 0.87, 95% confidence interval: 0.71-1.07], p = 0.198) between patients staged with or without 18F-FDG PET/CT. In the conventional imaging group, we found no survival difference between patients staged with or without bone scintigraphy. Although there were no differences in delivered radiotherapy dose, 18F-FDG PET/CT-staged patients received lower normal tissue (lung, heart, and esophagus) radiation doses. Apart from a higher incidence of late esophagitis in patients staged with conventional imaging (for grade ≥1, 19% versus 11%; [p = 0.012]), the incidence of acute and late radiotherapy-related toxicities was not different between the two groups. CONCLUSION: In CONVERT, survival outcomes were not significantly different in patients staged with or without 18F-FDG PET/CT. However, this analysis cannot support the use or omission of 18F-FDG PET/CT owing to study limitations.

Association of Chemoradiotherapy With Outcomes Among Patients With Stage I to II vs Stage III Small Cell Lung Cancer: Secondary Analysis of a Randomized Clinical Trial.

Importance: There is limited evidence to guide stage I to II small cell lung cancer (SCLC) treatment. Objective: To examine the characteristics and outcomes among patients with stage I to II SCLC treated with modern chemoradiotherapy. Design, Setting, and Participants: In this post hoc secondary analysis of the Concurrent Once-Daily vs Twice-Daily Radiotherapy Trial (CONVERT), a multicenter phase 3 trial conducted in patients with limited-stage SCLC from April 7, 2008, to November 29, 2013, patients with TNM stage I to II SCLC were compared with those with stage III disease. Data analysis was performed from November 1, 2017, to February 28, 2018. Interventions: In CONVERT, patients were randomized to receive twice-daily (45 Gy in 30 fractions) or once-daily (66 Gy in 33 fractions) chemoradiotherapy. Prophylactic cranial irradiation (PCI) was offered, if indicated. Main Outcomes and Measures: The primary trial end point was overall survival (OS). TNM staging information was collected prospectively; this was an unplanned analysis because stratification was not performed according to TNM stage. Results: A total of 509 (277 [54.4%] men; mean [SD] age, 61.5 [8.3] years) of 543 patients (93.7%) with TNM staging information were eligible for this subgroup analysis, and 86 of the 509 (16.9%) had TNM stage I to II disease. The median gross tumor volume was smaller in patients with stage I to II disease (38.4 cm3; range, 2.2-593.0 cm3) compared with patients with stage III disease (93 cm3; range, 0.5-513.4 cm3) (P < .001). No other significant differences were found in baseline and treatment characteristics and chemoradiotherapy adherence between the 2 groups or the number of patients with stage I to II disease (78 [90.7%]) and stage III disease (346 [81.8%]) who received PCI (P = .10). Patients with stage I to II disease achieved longer OS (median, 50 months [95% CI, 38 to not reached months] vs 25 months [95% CI, 21-29 months]; hazard ratio, 0.60 [95% CI, 0.44-0.83]; P = .001) compared with patients with stage III disease. In patients with stage I to II disease, no significant survival difference was found between the trial arms (median, 39 months in the once-daily arm vs 72 months in the twice-daily arm; P = .38). Apart from lower incidence of acute esophagitis in patients with stage I to II disease compared with patients with stage III disease (grade ≥3, 9 [11.3%] vs 82 [21.1%]; P < .001), the incidences of acute and late toxic effects were not significantly different. Conclusions and Relevance: Patients with stage I to II SCLC in CONVERT achieved long-term survival with acceptable toxic effects after chemoradiotherapy and PCI. This study suggests that patients with stage I to II small cell lung cancer treated with modern chemoradiotherapy have better outcomes compared with patients with stage III disease, providing information that practitioners can potentially give their patients to aid clinical decisions. Trial Registration: ClinicalTrials.gov identifier: NCT00433563.

A randomized control trial evaluating fluorescent ink versus dark ink tattoos for breast radiotherapy.

OBJECTIVE: The purpose of this UK study was to evaluate interfraction reproducibility and body image score when using ultraviolet (UV) tattoos (not visible in ambient lighting) for external references during breast/chest wall radiotherapy and compare with conventional dark ink. METHODS: In this non-blinded, single-centre, parallel group, randomized control trial, patients were allocated to receive either conventional dark ink or UV ink tattoos using computer-generated random blocks. Participant assignment was not masked. Systematic (∑) and random (σ) setup errors were determined using electronic portal images. Body image questionnaires were completed at pre-treatment, 1 month and 6 months to determine the impact of tattoo type on body image. The primary end point was to determine that UV tattoo random error (σsetup) was no less accurate than with conventional dark ink tattoos, i.e. <2.8 mm. RESULTS: 46 patients were randomized to receive conventional dark or UV ink tattoos. 45 patients completed treatment (UV: n = 23, dark: n = 22). σsetup for the UV tattoo group was <2.8 mm in the u and v directions (p = 0.001 and p = 0.009, respectively). A larger proportion of patients reported improvement in body image score in the UV tattoo group compared with the dark ink group at 1 month [56% (13/23) vs 14% (3/22), respectively] and 6 months [52% (11/21) vs 38% (8/21), respectively]. CONCLUSION: UV tattoos were associated with interfraction setup reproducibility comparable with conventional dark ink. Patients reported a more favourable change in body image score up to 6 months following treatment. Advances in knowledge: This study is the first to evaluate UV tattoo external references in a randomized control trial.

Clinical impact of IMPORT HIGH trial (CRUK/06/003) on breast radiotherapy practices in the United Kingdom.

OBJECTIVE: IMPORT HIGH is a multicentre randomized UK trial testing dose-escalated intensity-modulated radiotherapy (IMRT) after tumour excision in females with early breast cancer and higher than average local recurrence risk. A survey was carried out to investigate the impact of this trial on the adoption of advanced breast radiotherapy (RT) techniques in the UK. METHODS: A questionnaire was sent to all 26 IMPORT HIGH recruiting RT centres to determine whether the trial has influenced non-trial breast RT techniques in terms of volume delineation, dosimetry, treatment delivery and verification. In order to compare the clinical practice of breast RT between IMPORT HIGH and non-IMPORT HIGH centres, parts of the Royal College of Radiologists (RCR) breast RT audit result were used in this study. RESULTS: 26/26 participating centres completed the questionnaire. After joining the trial, the number of centres routinely using tumour bed clips to guide whole-breast RT rose from 5 (19%) to 21 (81%). 20/26 (77%) centres now contour target volumes and organs at risk (OARs) in some or all patients compared with 14 (54%) before the trial. 14/26 (54%) centres offer inverse-planned IMRT for selected non-trial patients with breast cancer, and 10/14 (71%) have adopted the IMPORT HIGH trial protocol for target volume and OARs dose constraints. Only 2/26 (8%) centres used clip information routinely for breast treatment verification prior to IMPORT HIGH, a minority that has since risen to 7/26 (27%). Data on 1386 patients was included from the RCR audit. This suggested that more cases from IMPORT HIGH centres had surgical clips implanted (83 vs 67%), were treated using CT guided planning with full three-dimensional dose compensation (100 vs 75%), and were treated with photon boost RT (30 vs 8%). CONCLUSION: The study suggests that participation in the IMPORT HIGH trial has played an important part in providing the guidance and support networks needed for the safe integration of advanced RT techniques, where appropriate, as a standard of care for breast cancer patients treated at participating cancer centres. ADVANCES IN KNOWLEDGE: We investigated the impact of the IMPORT HIGH trial on the adoption of advanced breast RT techniques in the UK and the trial has influenced non-trial breast RT techniques in terms of volume delineation, dosimetry, treatment delivery and verification.

A prospective study comparing radiographer- and clinician-based localization for patients with metastatic spinal cord compression (MSCC) to assess the feasibility of a radiographer-led service.

OBJECTIVE: To investigate whether there was parity between treatment fields localized by radiographers and clinicians, by comparing geographical variations and hence determining the feasibility of a radiographer-led service. METHODS: 23 patients with metastatic spinal cord compression (MSCC) were prospectively sampled. Four radiographers not involved in the original planning performed localization on each patient. The 92 localizations that they determined were compared with the clinician-approved fields. Agreement was defined as ≤0.5 cm between field length, width and three isocentre co-ordinates. To be feasible, agreement was required in a minimum of 97% of the cases. The potential time saved with a radiographer-led approach was also recorded. RESULTS: Agreement between clinicians and radiographers was 97.8%. For all field parameters, the average differences were <0.3 cm and were significantly different from the 0.5-cm median (p < 0.0001) that would establish no agreement using Wilcoxon signed-rank test. The average (range) delay awaiting clinician approval was 54 min (4-141 min). CONCLUSION: Strong agreement between radiographer and clinician localizations was established. It was also highlighted that time could be saved in the patient's pathway by removing the need to wait for clinician approval. We believe this supports a radiographer-led service. ADVANCES IN KNOWLEDGE: This article is novel, as it is the first known comparison between clinicians and radiographers in the localization of MSCC radiotherapy. These data show the feasibility of introducing radiographer-led practice and a methodology that could be potentially transferred to investigate the localization parity for other treatment sites.

The UK HeartSpare Study (Stage IB): randomised comparison of a voluntary breath-hold technique and prone radiotherapy after breast conserving surgery.

PURPOSE: To compare mean heart and left anterior descending coronary artery (LAD) doses (NTDmean) and positional reproducibility in larger-breasted women receiving left breast radiotherapy using supine voluntary deep-inspiratory breath-hold (VBH) and free-breathing prone techniques. MATERIALS AND METHODS: Following surgery for early breast cancer, patients with estimated breast volumes >750 cm(3) underwent planning-CT scans in supine VBH and free-breathing prone positions. Radiotherapy treatment plans were prepared, and mean heart and LAD doses were calculated. Patients were randomised to receive one technique for fractions 1-7, before switching techniques for fractions 8-15 (40 Gy/15 fractions total). Daily electronic portal imaging and alternate-day cone-beam CT (CBCT) imaging were performed. The primary endpoint was the difference in mean LAD NTDmean between techniques. Population systematic (Σ) and random errors (σ) were estimated. Within-patient comparisons between techniques used Wilcoxon signed-rank tests. RESULTS: 34 patients were recruited, with complete dosimetric data available for 28. Mean heart and LAD NTDmean doses for VBH and prone treatments respectively were 0.4 and 0.7 (p<0.001) and 2.9 and 7.8 (p<0.001). Clip-based CBCT errors for VBH and prone respectively were ⩽3.0 mm and ⩽6.5 mm (Σ) and ⩽3.5 mm and ⩽5.4 mm (σ). CONCLUSIONS: In larger-breasted women, supine VBH provided superior cardiac sparing and reproducibility than a free-breathing prone position.

Voluntary breath-hold technique for reducing heart dose in left breast radiotherapy.

Breath-holding techniques reduce the amount of radiation received by cardiac structures during tangential-field left breast radiotherapy. With these techniques, patients hold their breath while radiotherapy is delivered, pushing the heart down and away from the radiotherapy field. Despite clear dosimetric benefits, these techniques are not yet in widespread use. One reason for this is that commercially available solutions require specialist equipment, necessitating not only significant capital investment, but often also incurring ongoing costs such as a need for daily disposable mouthpieces. The voluntary breath-hold technique described here does not require any additional specialist equipment. All breath-holding techniques require a surrogate to monitor breath-hold consistency and whether breath-hold is maintained. Voluntary breath-hold uses the distance moved by the anterior and lateral reference marks (tattoos) away from the treatment room lasers in breath-hold to monitor consistency at CT-planning and treatment setup. Light fields are then used to monitor breath-hold consistency prior to and during radiotherapy delivery.

Diffusion-weighted imaging of the high-risk breast: Apparent diffusion coefficient values and their relationship to breast density.

PURPOSE: To document the apparent diffusion coefficient (ADC) of fibroglandular breast tissue in women at high-risk of developing breast cancer and investigate the relationship between ADC and breast density. MATERIALS AND METHODS: Local research ethics approval was obtained. A total of 33 high-risk women including 17 BRCA1/2 mutation carriers (mean age, 43 years) and 16 women postmantle irradiation (mean age 40 years) underwent diffusion-weighted MRI between days 6 and 16 of their menstrual cycle. ADC histograms from a region of interest in fibroglandular tissue and mammographic breast density measurements were obtained. Mean, percentile ADC values (10th, 25th, 50th, 75th, 90th) and skew were compared for the two groups; ADC and mammographic breast density were correlated. RESULTS: Mean ADC values (×10(-6) mm(2) /s) were 2017 ± 197 in postmantle irradiated women and 1827 ± 289 in BRCA1/2 mutation carriers (P = 0.035) with significant differences at all percentiles (P < 0.0001) but not skew (P = 0.44). ADC values showed weak positive correlation with mammographic breast density in BRCA1/2 mutation carriers (r = 0.51, P = 0.043) but not in postmantle radiotherapy patients (r = 0.49, P = 0.13). CONCLUSION: Higher ADC values seen in fibroglandular tissue postmantle irradiation compared with BRCA1/2 mutation carriers has potential to improve tumor detection in these patients. Lack of correlation between ADC and breast density postmantle irradiation may be a result of microstructural changes.

The UK HeartSpare Study: randomised evaluation of voluntary deep-inspiratory breath-hold in women undergoing breast radiotherapy.

PURPOSE: To determine whether voluntary deep-inspiratory breath-hold (v_DIBH) and deep-inspiratory breath-hold with the active breathing coordinator™ (ABC_DIBH) in patients undergoing left breast radiotherapy are comparable in terms of normal-tissue sparing, positional reproducibility and feasibility of delivery. METHODS: Following surgery for early breast cancer, patients underwent planning-CT scans in v_DIBH and ABC_DIBH. Patients were randomised to receive one technique for fractions 1-7 and the second technique for fractions 8-15 (40 Gy/15 fractions total). Daily electronic portal imaging (EPI) was performed and matched to digitally-reconstructed radiographs. Cone-beam CT (CBCT) images were acquired for 6/15 fractions and matched to planning-CT data. Population systematic (Σ) and random errors (σ) were estimated. Heart, left-anterior-descending coronary artery, and lung doses were calculated. Patient comfort, radiographer satisfaction and scanning/treatment times were recorded. Within-patient comparisons between the two techniques used the paired t-test or Wilcoxon signed-rank test. RESULTS: Twenty-three patients were recruited. All completed treatment with both techniques. EPI-derived Σ were ≤ 1.8mm (v_DIBH) and ≤ 2.0mm (ABC_DIBH) and σ ≤ 2.5mm (v_DIBH) and ≤ 2.2mm (ABC_DIBH) (all p non-significant). CBCT-derived Σ were ≤ 3.9 mm (v_DIBH) and ≤ 4.9 mm (ABC_DIBH) and σ ≤ 4.1mm (v_DIBH) and ≤ 3.8mm (ABC_DIBH). There was no significant difference between techniques in terms of normal-tissue doses (all p non-significant). Patients and radiographers preferred v_DIBH (p=0.007, p=0.03, respectively). Scanning/treatment setup times were shorter for v_DIBH (p=0.02, p=0.04, respectively). CONCLUSIONS: v_DIBH and ABC_DIBH are comparable in terms of positional reproducibility and normal tissue sparing. v_DIBH is preferred by patients and radiographers, takes less time to deliver, and is cheaper than ABC_DIBH.

Lymphocyte radiosensitivity in BRCA1 and BRCA2 mutation carriers and implications for breast cancer susceptibility.

There is conflicting evidence as to whether individuals who are heterozygous for germ-line BRCA1 or BRCA2 mutations have an altered phenotypic cellular response to irradiation. To investigate this, chromosome breakage and apoptotic response were measured after irradiation in peripheral blood lymphocytes from 26 BRCA1 and 18 BRCA2 mutation carriers without diagnosed breast cancer, and 38 unaffected age, ethnically and sex-matched controls. To assess the role of BRCA1 and BRCA2 in homologous recombination, an S phase enrichment chromosome breakage assay was used. BrdUrd incorporation studies allowed verification of the correct experimental settings. We found that BRCA1 mutation carriers without cancer had increased chromosome breaks as well as breaks and gaps per cell post irradiation using the classical G2 assay (p = 0.01 and 0.004, respectively) and the S phase enrichment assay (p = 0.01 and 0.01, respectively) compared to age-matched unaffected controls. BRCA2 mutation carriers without cancer had increased breaks as well as breaks and gaps per cell post irradiation using the S phase enrichment assay (p = 0.045 and 0.012, respectively). No difference was detected using the G2 assay (p = 0.88 and 0.40 respectively). BRCA1 and BRCA2 mutation carriers had normal cell cycle kinetics and apoptotic response to irradiation compared to age-matched controls. Our results show a demonstrable impairment in irradiation induced DNA repair in women with heterozygous germline BRCA1 and BRCA2 mutations prior to being diagnosed with breast cancer.

Gene promoter hypermethylation in ductal lavage fluid from healthy BRCA gene mutation carriers and mutation-negative controls.

INTRODUCTION: Female germline BRCA gene mutation carriers are at increased risk for developing breast cancer. The purpose of our study was to establish whether healthy BRCA mutation carriers demonstrate an increased frequency of aberrant gene promoter hypermethylation in ductal lavage (DL) fluid, compared with predictive genetic test negative controls, that might serve as a surrogate marker of BRCA1/2 mutation status and/or breast cancer risk. METHODS: The pattern of CpG island hypermethylation within the promoter region of a panel of four genes (RAR-beta, HIN-1, Twist and Cyclin D2) was assessed by methylation-specific polymerase chain reaction using free DNA extracted from DL fluid. RESULTS: Fifty-one DL samples from 24 healthy women of known BRCA mutation status (7 BRCA1 mutation carriers, 12 BRCA2 mutation carriers and 5 controls) were available for methylation analysis. Eight of 19 (42.1%) BRCA mutation carriers were found to have at least one hypermethylated gene in the four-gene panel. Two BRCA mutation carriers, in whom aberrant methylation was found, also had duct epithelial cell atypia identified. No hypermethylation was found in DL samples from 5 negative controls (p = 0.13). CONCLUSION: We found substantial levels of aberrant methylation, with the use of a four-gene panel, in the fluid from the breasts of healthy BRCA mutation carriers compared with controls. Methylation analysis of free DNA in DL fluid may offer a useful surrogate marker for BRCA1/2 mutation status and/or breast cancer risk. Further studies are required for the evaluation of the specificity and predictive value of aberrant methylation in DL fluid for future breast cancer development in BRCA1/2 mutation carriers.

Proteomic analysis of nipple aspirate fluid throughout the menstrual cycle in healthy pre-menopausal women.

A proteomic approach to nipple aspiration fluid (NAF) has been used in a number of studies comparing women with breast cancer and healthy women. However, to make useful comparisons between women with breast cancer and healthy women it is necessary to establish whether there is physiological variation in the proteomic profiles of NAF. The purpose of this study was, for the first time, to examine how the proteomic profile of NAF using surface-enhanced laser desorption ionisation time-of-flight mass spectrometry varies across the menstrual cycle in healthy pre-menopausal women. Twelve women were recruited and nipple aspiration was carried out weekly from both breasts of each subject for two menstrual cycles. Matching serum samples for luteinising hormone, follicle stimulating hormone and oestradiol were obtained at each aspiration attempt. Statistically significant peaks were found for three healthy volunteers (p < 0.05). However, the peaks that varied across the menstrual cycle were different from one healthy volunteer to another and the differences were small compared with the large variation in proteomic profiles between healthy volunteers. This study provides proof of concept that the NAF proteomic profile does not vary substantially during the menstrual cycle and that therefore it is valid to compare NAF profiles from pre-menopausal women that have been taken at different stages in the menstrual cycle.