Variability of gross tumour volume delineation: MRI and CT based tumour and lymph node delineation for lung radiotherapy.

PURPOSE: To compare gross tumour volume (GTV) delineation of lung cancer on magnetic resonance imaging (MRI) and positron emission tomography (PET) versus computed tomography (CT) and PET. METHODS: Three experienced thoracic radiation oncologists delineated GTVs on twenty-six patients with lung cancer, based on CT registered to PET, T2-weighted MRI registered to PET and T1-weighted MRI registered with PET. All observers underwent education on reviewing T1 and T2 images along with guidance on window and level setup. Interobserver and intermodality variation was performed based on dice similarity coefficient (DSC), Hausdorff distance (HD), and average Hausdorff distance (AvgHD) metrics. To compute interobserver variability (IOV) a simultaneous truth and performance level estimation (STAPLE) volume for each image modality was used as reference volume. For intermodality analysis, each observers CT based primary and nodal GTV was used as reference volume. RESULTS: A mean DSC of 0.9 across all observers for primary GTV (GTVp) and a DSC of >0.7 for nodal GTV (GTVn) was demonstrated for IOV. Mean T2 and T1 GTVp and GTVn were smaller than CT GTVp and GTVn but the difference in volume between modalities was not statistically significant. Significant difference (p < 0.01) for GTVp and GTVn was found between T2 and T1 GTVp and GTVn compared to CT GTVp and GTVn based on DSC metrics. Large variation in volume similarity was noted based on HD of up-to 5.4 cm for observer volumes compared to STAPLE volume. CONCLUSION: Interobserver variability in GTV delineation was similar for MRI and PET versus CT and PET. The significant difference between MRI compared to CT delineated volumes needs to be further explored.

Can reducing planning safety margins broaden the inclusion criteria for lung stereotactic ablative body radiotherapy?

INTRODUCTION: Stereotactic ablative body radiotherapy (SABR) is currently indicated for inoperable, early-stage non-small cell lung carcinoma (NSCLC). Advancements in image-guidance technology continue to improve treatment precision and enable reductions in planning safety margins. We investigated the dosimetric benefits of margin reduction, its potential to extend SABR to more NSCLC patients and the factors influencing plan acceptability. METHODS: This retrospective analysis included 61 patients (stage IA-IIIA) treated with conventional radiotherapy. Patients were ineligible for SABR due to tumour size or proximity to organs at risk (OAR). Using Pinnacle auto-planning, three SABR plans were generated for each patient: a regular planning target volume margin plan, a reduced margin plan (gross tumour volume GTV+3 mm) and a non-margin plan. Targets were planned to 48Gy/4 or 50Gy/5 fractions depending on location. Plans were compared in terms of target coverage, OAR doses and dosimetric acceptability based on local guidelines. Predictors of acceptability were investigated using logistic regression analysis. RESULTS: Compared to regular margin plans, both reduced margin and non-margin plans resulted in significant reductions to almost all dose constraints. Dose conformity was significantly worse in non-margin plans (P < 0.05) and strongly correlated with targets' surface area/volume ratio (R2  = 0.9, P < 0.05). 26% of reduced margin plans were acceptable, compared to 54% of non-margin plans. GTV overlap with OARs significantly affected plan acceptability (OR 0.008, 95% CI 0.001-0.073). CONCLUSION: Margin reduction significantly reduced OAR doses enabling acceptable plans to be achieved for patients previously excluded from SABR. Indications for lung SABR may broaden as treatment accuracy continues to improve; further work is needed to identify patients most likely to benefit.

The effect of imaging modality (magnetic resonance imaging vs. computed tomography) and patient position (supine vs. prone) on target and organ at risk doses in partial breast irradiation.

INTRODUCTION: Conventionally computed tomography (CT) has been used to delineate target volumes in radiotherapy; however, magnetic resonance imaging (MRI) is being continually integrated into clinical practice; therefore, the investigation into targets derived from MRI is warranted. The purpose of this study was to evaluate the impact of imaging modality (MRI vs. CT) and patient positioning (supine vs. prone) on planning target volumes (PTVs) and organs at risk (OARs) for partial breast irradiation (PBI). METHODS: A retrospective data set, of 35 patients, was accessed where each patient had undergone MRI and CT imaging for tangential whole breast radiotherapy in both the supine and prone position. PTVs were defined from seroma cavity (SC) volumes delineated on each respective image, resulting in 4 PTVs per patient. PBI plans were generated with 6MV external beam radiotherapy (EBRT) using the TROG 06.02 protocol guidelines. A prescription of 38.5Gy in 10 fractions was used for all cases. The impact analysis of imaging modality and patient positioning included dose to PTVs, and OARs based on agreed criteria. Statistical analysis was conducted though Mann-Whitey U, Fisher's exact and chi-squared testing (P < 0.005). RESULTS: Twenty-four patients were eligible for imaging analysis. However, positioning analysis could only be investigated on 19 of these data sets. No statistically significant difference was found in OAR doses based on imaging modality. Supine patient position resulted in lower contralateral breast dose (0.10Gy ± 0.35 vs. 0.33Gy ± 0.78, p = 0.011). Prone positioning resulted in a lower dose to ipsilateral lung volumes (10.85Gy ± 11.37 vs. 3.41Gy ± 3.93, P = <0.001). CONCLUSIONS: PBI plans with PTVs derived from MRI exhibited no clinically significant differences when compared to plans created from CT in relation to plan compliance and OAR dose. Patient position requires careful consideration regardless of imaging modality chosen. Although there was no proven superiority of MRI derived target volumes, it indicates that MRI could be considered for PBI target delineation.

Palliative care and psychosocial care in metastatic non-small cell lung cancer: factors affecting utilisation of services and impact on patient survival.

BACKGROUND: Palliative care (PC) and psychosocial care (PSC) are essential services, which can positively impact on quality of life in patients with metastatic lung cancer, when advanced disease and poor prognosis preclude the use of curative therapies. The aims of this study were to describe patterns of PC and PSC and identify factors associated with service utilisation and overall patient survival. METHOD: A retrospective Australian cohort of South Western Sydney residents with newly diagnosed stage IV non-small cell lung cancer (NSCLC) in 2006-2012 was identified from the Local Health District Clinical Cancer Registry. Supplemental information was sourced from the area PC database and hospital medical records. Cox regression models with robust variance identified factors associated with PC and PSC and examined patient survival. RESULTS: A total of 923 patients were identified. Eighty-three per cent of patients were seen by PC, with 67% seen within 8 weeks of diagnosis. PSC utilisation was 82%. Radiotherapy treatment and residential area were associated with both PC and PSC. Increasing age was associated with early PC referral. Median overall survival was 4 months. PC was associated with patient survival; however, the effect varied over time. CONCLUSION: The rate of PC and PSC in our metastatic NSCLC population was high when compared with published data. Despite this, there were gaps in PC and PSC provision in this population, notably with patients not receiving active treatment, and those receiving systemic therapy utilising these services less frequently. PSC and PC contact were not convincingly associated with improved patient survival.

Variations in breast cancer histology and treatment patterns between the major ethnic groups of South West Sydney.

Studies in the United States and United Kingdom have demonstrated ethnic variations in breast cancer receptor status, histology, and treatment access. This study aimed to investigate whether ethnicity variation similarly exists in Australia. Patients diagnosed with breast cancer between 2006 and 2011 across all public hospitals in the South Western Sydney Local Health District were identified and patient data collected retrospectively. Logistic regression analysis was used to measure the association between various biologic and treatment parameters and ethnicity. Ethnicity was found to have an influence on age of diagnosis, histology, treatment utilization, and recurrence in breast cancer patients.

The impact of imaging modality (CT vs MRI) and patient position (supine vs prone) on tangential whole breast radiation therapy planning.

PURPOSE: The purpose of this study was to evaluate the impact of magnetic resonance imaging (MRI) versus computed tomography (CT)-derived planning target volumes (PTVs), in both supine and prone positions, for whole breast (WB) radiation therapy. METHODS AND MATERIALS: Four WB radiation therapy plans were generated for 28 patients in which PTVs were generated based on CT or MRI data alone in both supine and prone positions. A 6-MV tangential intensity modulated radiation therapy technique was used, with plans designated as ideal, acceptable, or noncompliant. Dose metrics for PTVs and organs at risk were compared to analyze any differences based on imaging modality (CT vs MRI) or patient position (supine vs prone). RESULTS: With respect to imaging modality 2/11 whole breast planning target volume (WB_PTV) dose metrics (percentage of PTV receiving 90% and 110% of prescribed dose) displayed statistically significant differences; however, these differences did not alter the average plan compliance rank. With respect to patient positioning, the odds of having an ideal plan versus a noncompliant plan were higher for the supine position compared with the prone position (P = .026). The minimum distance between the seroma cavity planning target volume (SC_PTV) and the chest wall was increased with prone positioning (P < .001, supine and prone values 1.1 mm and 8.7 mm, respectively). Heart volume was greater in the supine position (P = .005). Heart doses were lower in the supine position than prone (P < .01, mean doses 3.4 ± 1.55 Gy vs 4.4 ± 1.13 Gy for supine vs prone, respectively). Mean lung doses met ideal dose constraints in both positions, but were best spared in the prone position. The contralateral breast maximum dose to 1cc (D1cc) showed significantly lower doses in the supine position (P < .001, 4.64 Gy vs 9.51 Gy). CONCLUSIONS: Planning with PTVs generated from MRI data showed no clinically significant differences from planning with PTVs generated from CT with respect to PTV and doses to organs at risk. Prone positioning within this study reduced mean lung dose and whole heart volumes but increased mean heart and contralateral breast doses compared with supine.

What quality-of-life issues do women with ductal carcinoma in situ (DCIS) consider important when making treatment decisions?

PURPOSE: To explore quality-of-life (QOL) issues considered important when deciding on treatment for ductal carcinoma in situ (DCIS). METHODS: Breast Cancer Network of Australia members diagnosed with DCIS in the past 5 years (self-identified) participated in an online survey (Sep-Nov 2015). From a list of 74 QOL issues, participants selected all issues they experienced during DCIS diagnosis, treatment or recovery, then the issues they felt important to making a DCIS treatment decision, and completed the Health Literacy Questionnaire (HLQ). Associations between QOL issues and self-reported treatment received were assessed with χ 2 tests. RESULTS: The primary analysis included 38 participants treated with breast-conserving surgery (n = 15), mastectomy (n = 23), and/or radiotherapy (n = 14). Fatigue-related symptoms (82%) and "fear of progression" (50%) were the most frequently-experienced issues. When deciding on DCIS treatment, the most important consideration was "fear of progression" (50%). A higher proportion of mastectomy (compared to non-mastectomy) patients considered "difficultly looking at yourself naked" (p = 0.03). Radiotherapy (compared to non-radiotherapy) patients were more likely to consider "feeling unwell" important (p = 0.006). Results were similar in a sensitivity analysis involving all 101 respondents (i.e., including 63 respondents who reported receiving chemotherapy, endocrine therapy, and/or Herceptin, suggesting that they may have been treated for invasive breast cancer). Health literacy was high across all nine HLQ scales. CONCLUSION: Fear of progression is a key consideration in DCIS treatment decision making for women with high health literacy. QOL treatment considerations differed by treatments received. Women diagnosed with DCIS may benefit from evidence about QOL to inform treatment decision making.

Comparison of Magnetic Resonance Imaging and Computed Tomography for Breast Target Volume Delineation in Prone and Supine Positions.

PURPOSE: To determine whether T2-weighted MRI improves seroma cavity (SC) and whole breast (WB) interobserver conformity for radiation therapy purposes, compared with the gold standard of CT, both in the prone and supine positions. METHODS AND MATERIALS: Eleven observers (2 radiologists and 9 radiation oncologists) delineated SC and WB clinical target volumes (CTVs) on T2-weighted MRI and CT supine and prone scans (4 scans per patient) for 33 patient datasets. Individual observer's volumes were compared using the Dice similarity coefficient, volume overlap index, center of mass shift, and Hausdorff distances. An average cavity visualization score was also determined. RESULTS: Imaging modality did not affect interobserver variation for WB CTVs. Prone WB CTVs were larger in volume and more conformal than supine CTVs (on both MRI and CT). Seroma cavity volumes were larger on CT than on MRI. Seroma cavity volumes proved to be comparable in interobserver conformity in both modalities (volume overlap index of 0.57 (95% Confidence Interval (CI) 0.54-0.60) for CT supine and 0.52 (95% CI 0.48-0.56) for MRI supine, 0.56 (95% CI 0.53-0.59) for CT prone and 0.55 (95% CI 0.51-0.59) for MRI prone); however, after registering modalities together the intermodality variation (Dice similarity coefficient of 0.41 (95% CI 0.36-0.46) for supine and 0.38 (0.34-0.42) for prone) was larger than the interobserver variability for SC, despite the location typically remaining constant. CONCLUSIONS: Magnetic resonance imaging interobserver variation was comparable to CT for the WB CTV and SC delineation, in both prone and supine positions. Although the cavity visualization score and interobserver concordance was not significantly higher for MRI than for CT, the SCs were smaller on MRI, potentially owing to clearer SC definition, especially on T2-weighted MR images.

Hypofractionated versus conventionally fractionated radiotherapy for ductal carcinoma in situ (DCIS) of the breast.

INTRODUCTION: Hypofractionated radiotherapy (RT) in the setting of early invasive breast cancer has been shown to have similar local control rates and cosmetic outcomes as conventionally fractionated RT. This study compares ipsilateral recurrence rates between hypofractionated and conventional RT, with and without a boost. The effect of hypofractionated RT and chest wall separation (CWS) on cosmetic outcome was also assessed. METHODS: All patients with ductal carcinoma in situ (DCIS) treated between 1998 and 2012 across two sites of a single cancer institution were retrospectively studied. Patients were analysed according to those receiving conventional RT (≤2 Gy per fraction) and those receiving hypofractionated RT (>2 Gy per fraction), as well as the presence or absence of a tumour bed boost. Data were collected through electronic medical records and local cancer registry. Cosmetic outcome was scored by physicians on a four-point scale during clinical follow-up appointments. RESULTS: One hundred and ninety-seven patients were treated for DCIS during the study period. One hundred and forty-one were treated with conventional RT, and 56 with hypofractionated RT. After a median follow up of 4.4 years, there were 12 ipsilateral recurrences, of which seven were invasive disease and five DCIS. Ten recurrences occurred in patients who received conventional RT (7.1% recurrence rate) and two in those who received hypofractionated RT (3.6% recurrence rate) (P = 0.48). Cosmetic outcomes were not significantly different between conventional and hypofractionated RT (P = 0.06). CONCLUSIONS: Hypofractionation represents a suitable alternative for treating DCIS in the absence of randomised data.

Assessment of MRI image quality for various setup positions used in breast radiotherapy planning.

This study investigates breast magnetic resonance imaging (MRI) image quality for 3 different breast radiotherapy positions (prone, supine flat and supine inclined) and associated choice of breast coils. Supine breast MRI has comparable image quality to prone breast MRI for the purposes of radiotherapy delineation for T2-weighted sequences.

Do patients discussed at a lung cancer multidisciplinary team meeting receive guideline-recommended treatment?

AIM: Clinical guidelines provide evidence-based management recommendations to guide practice. This study aimed to evaluate whether patients discussed at a lung cancer multidisciplinary team meeting received guideline-recommended treatment and determine reasons for not receiving guideline-recommended treatment. METHODS: All new lung cancer patients discussed at the Liverpool/Macarthur lung cancer multidisciplinary team meeting between 1 December 2005 and 31 December 2010 were included. Guideline-recommended treatment was assigned according to pathology, stage and ECOG (Eastern Co-operative Oncology Group) performance status as per the 2004 Australian Lung Cancer Guidelines. This was compared with actual treatment received to determine adherence to guidelines. For those patients who did not receive guideline-recommended treatment, the medical record was reviewed to determine the reason(s) for this. Survival was compared between those who did and did not receive guideline-recommended treatment. RESULTS: 808 new patients were discussed at the multidisciplinary team meeting. Guideline-recommended treatment could not be assigned in 2% of patients due to missing data. 435 patients (54%) received guideline-recommended treatment, and 356 (44%) did not. The most common reasons for not receiving guideline-recommended treatment were a decline in ECOG performance status (24%), large tumor volume precluding radical radiotherapy (17%), comorbidities (15%) and patient preference (13%). Patients less than 70 years who received guideline-recommended treatment had improved survival compared with those who did not. CONCLUSIONS: A significant proportion of lung cancer patients did not receive guideline-recommended treatment due to legitimate reasons. Alternative guidelines are needed for patients not suitable for current best practice. Treatment according to guidelines was a predictor for survival.

MRI geometric distortion: Impact on tangential whole-breast IMRT.

The purpose of this study was to determine the impact of magnetic resonance imaging (MRI) geometric distortions when using MRI for target delineation and planning for whole-breast, intensity-modulated radiotherapy (IMRT). Residual system distortions and combined systematic and patient-induced distortions are considered. This retrospective study investigated 18 patients who underwent whole-breast external beam radiotherapy, where both CT and MRIs were acquired for treatment planning. Distortion phantoms were imaged on two MRI systems, dedicated to radiotherapy planning (a wide, closed-bore 3T and an open-bore 1T). Patient scans were acquired on the 3T system. To simulate MRI-based planning, distortion maps representing residual system distortions were generated via deformable registration between phantom CT and MRIs. Patient CT images and structures were altered to match the residual system distortion measured by the phantoms on each scanner. The patient CTs were also registered to the corresponding patient MRI scans, to assess patient and residual system effects. Tangential IMRT plans were generated and optimized on each resulting CT dataset, then propagated to the original patient CT space. The resulting dose distributions were then evaluated with respect to the standard clinically acceptable DVH and visual assessment criteria. Maximum residual systematic distortion was measured to be 7.9 mm (95%<4.7mm) and 11.9 mm (95%<4.6mm) for the 3T and 1T scanners, respectively, which did not result in clinically unacceptable plans. Eight of the plans accounting for patient and systematic distortions were deemed clinically unacceptable when assessed on the original CT. For these plans, the mean difference in PTV V95 (volume receiving 95% prescription dose) was 0.13±2.51% and -0.73±1.93% for right- and left-sided patients, respectively. Residual system distortions alone had minimal impact on the dosimetry for the two scanners investigated. The combination of MRI systematic and patient-related distortions can result in unacceptable dosimetry for whole-breast IMRT, a potential issue when considering MRI-only radiotherapy treatment planning. PACS number(s): 87.61.-c, 87.57.cp, 87.57.nj, 87.55.D.

Australian survey on current practices for breast radiotherapy.

INTRODUCTION: Detailed, published surveys specific to Australian breast radiotherapy practice were last conducted in 2002. More recent international surveys specific to breast radiotherapy practice include a European survey conducted in 2008/2009 and a Spanish survey conducted in 2009. Radiotherapy techniques continue to evolve, and the utilisation of new techniques, such as intensity-modulated radiation therapy (IMRT), is increasing. This survey aimed to determine current breast radiotherapy practices across Australia. METHOD: An online survey was completed by 50 of the 69 Australian radiation therapy treatment centres. RESULTS: Supine tangential beam whole breast irradiation remains the standard of care for breast radiotherapy in Australia. A growing number of institutions are exploring prone positioning and IMRT utilisation. This survey demonstrated a wide variation in the benchmarks used to limit and report organ at risk doses, prescribed dose regimen, and post-mastectomy bolus practices. This survey also indicated, when compared with international literature, that there may be less interest in or uptake of external beam partial breast irradiation, prone positioning, simultaneous integrated boost and breath hold techniques. These are areas where further review and research may be warranted to ensure Australian patients are receiving the best care possible based on the best evidence available. CONCLUSION: This survey provides insight into the current radiotherapy practice for breast cancer in Australia.

Do multidisciplinary team meetings make a difference in the management of lung cancer?

BACKGROUND: There is limited evidence regarding the effectiveness of multidisciplinary team (MDT) meetings in lung cancer. The objective of this study was to compare the patterns of care for patients with newly diagnosed lung cancer who were presented at a lung cancer MDT meeting with the patterns of care for patients who were not presented. METHODS: All patients who had lung cancer newly diagnosed in South West Sydney (SWS) between December 1, 2005, and December 31, 2008, were identified from the local Clinical Cancer Registry. Patient and tumor characteristics and treatment receipt were compared between patients who were and were not presented at MDT meetings. A logistic regression model was constructed to determine predictors for receiving treatment and survival. RESULTS: In total, there were 988 patients, including 504 patients who were presented at MDT meetings and 484 who were not presented at MDT meetings. The median patient age was 69 years and 73 years in the MDT group and the non-MDT group, respectively (P < .01). There was no pathologic diagnosis for 13% of non-MDT patients compared with 4% of MDT patients (P < .01). Treatment receipt for MDT patients versus non-MDT patients was 12% versus 13%, respectively, for surgery (P value nonsignificant); 66% versus 33%, respectively, for radiotherapy (P < .001); 46% versus 29%, respectively, for chemotherapy (P < .001); and 66% versus 53%, respectively, for palliative care (P < .001). In patients with good performance status, the MDT group had significantly better receipt of radiotherapy among patients with stage I through IV nonsmall cell lung cancer (NSCLC) and had significantly better receipt of chemotherapy among patients with stage IV NSCLC. MDT discussion was an independent predictor of receiving radiotherapy, chemotherapy, and referral to palliative care but did not influence survival. CONCLUSIONS: MDT discussion was associated with better treatment receipt, which potentially may improve quality of life for patients with lung cancer. However, it did not improve survival.

Neurotoxicity of angiographic carbon dioxide in the cerebral vasculature.

RATIONALE AND OBJECTIVES: This study was undertaken to resolve conflicting evidence about the neurotoxicity of carbon dioxide gas as an angiographic contrast medium within the cerebral vasculature. MATERIALS AND METHODS: Single intracarotid injections or five consecutive intracarotid injections, at 2-minute intervals, of carbon dioxide, iopromide or saline, were given to 32 rabbits under clinically relevant conditions. Extravasation of Evans blue and Tc-pertechnetate was used to determine blood-brain barrier damage at 30 minutes or 6 hours after injection. At 6 hours after multiple injections, brains were removed for histologic examination. RESULTS: A single intracarotid injection of carbon dioxide caused minimal blood-brain barrier breakdown, whereas multiple injections caused significant breakdown that was still present at 6 hours after the injections. All carbon dioxide-injected brains that underwent histologic examination showed evidence of irreversible brain damage in the injected hemisphere. CONCLUSIONS: The study confirms the neurotoxicity of carbon dioxide within the cerebral vasculature and its unsuitability for clinical use in cerebral angiography.