A strategy to reduce fraction number in peripheral lung stereotactic ablative body radiotherapy.

Background and purpose: Hypo-fractionated lung Stereotactic Ablative Body Radiotherapy (SABR) has often been avoided when tumours are close to the chest wall. Our strategic objective was the reduction of fraction number, while maintaining target biological effective dose coverage without increasing chest wall toxicity (CWT) predictors. Materials and methods: Twenty previously treated lung SABR patients were stratified into four cohorts according to distance from PTV to the chest wall, <1 cm, <0.5 cm, overlapping up to 0.5 cm and 1.0 cm. For each patient, four plans were created; a chest wall optimised plan for 54 Gy in 3 fractions, the clinical plan re-prescribed for 55 Gy in 5, 48 Gy in 3 and 45 Gy in 3 fractions. Results: For a PTV distance of 0.5-0.0 cm, a reduction of the median (range) Dmax from 55.7 (57.5-54.1) Gy to 40.0 (37.1-42.0 Gy) Gy was observed for the chest wall optimised plans. The median V30Gy decreased from 18.9 (9.7-25.6) cm3 to 3.1 (1.8-4.5) cm3. For a PTV overlap of up to 0.5 cm, the Dmax reduced from 66.5 (64.1-70) Gy to 53.2 (50.6-55.1) Gy. The V30Gy decreased from 21.5 (16.5-29.5) cm3 to 14.9 (11.3-20.2) cm3. For the cohort with up to 1.0 cm overlap, there was a reduction in Dmax values of 9.9 Gy. The V30Gy for clinical plans, at 66.8 (18.7-188.8) cm3, decreased to 55.3 (15.5-149) cm3. Conclusion: When PTVs are within 0.5 cm of chest wall, lung SABR dose heterogeneity can be used to reduce fraction number without increasing CWT predictors.

Quantification of Organ Motion in Male and Female Patients Undergoing Long-Course Radiation Therapy for Rectal Cancer in the Supine Position.

Purpose: Previous studies have reported data on the internal rectal motion of patients with rectal cancer treated in the prone position. With the introduction of intensity modulated techniques, more patients are treated in the more reproducible supine position. Data informing specific margins for this treatment position are sparse, as are data comparing rectal motion characteristics and factors in male and female patients. The purpose of this retrospective study was to quantify and compare the interfractional rectal movement characteristics of male and female patients with rectal cancer treated with long-course chemoradiation therapy in the supine position. The data will aid the generation of internal target volume margins accounting for this organ's internal physiological movements. Methods and Materials: Cone beam computed tomography (CBCT) images were acquired from 19 male and 16 female patients with rectal cancer on the first 3 days of treatment and weekly thereafter. The rectum, bladder, and femoral heads were delineated on the planning CT (PCT) and 6 CBCT for each patient. Overall, 245 images were analyzed. All patients were treated with a full bladder. The rectum was divided into three 5-cm segments (upper, mid, and lower). The motion of the rectum was quantified by documenting the anteroposterior and lateral distances as measured using fixed anatomic landmarks, namely from the anterior aspect of the sacrum and mid-left femoral head, respectively. These measurements were taken at 1-cm intervals from the inferior border of L5 vertebrae. The sigmoid was excluded from these measurements. Estimations of systematic and random physiological movement error were determined and margins were calculated. Results: Two hundred forty-five image sets (19 PCT + 114 CBCT for male, 16 PCT + 96 CBCT for female) on patients who had undergone long-course radiation therapy were analyzed. Rectal tumor location was 31% in the inferior rectum, 46% in the mid rectum, and 23% in the superior rectum. Random rectal motion (mean of the per-patient standard deviation [σ]) was largest for the upper and mid rectum in the anterior direction. There were statistically significant differences in σ between male and female patients in the left lateral motion of the mid and inferior rectum as well as the anterior, posterior, and right motion of the inferior rectum (mid left: P < .0005; lower left: P < .0005; lower posterior: P = .001; lower anterior: P = .032; lower right: P = .001). Suggested internal target volume margin guidelines are therefore nonisotropic and vary per segment of rectum and sex. Conclusions: In our present study, interfractional rectal motion is shown to be significantly different between male and female patients. Our data suggest that the use of asymmetrical sex-specific margins in patients with rectal cancer treated in the supine position should be considered.

Long-term control of melanoma adrenal metastasis treated with radiotherapy.

Melanoma remains a large global burden with a significant proportion of patients succumbing to metastatic disease. The adrenal gland is a common area for metastasis with surgical treatment as the main modality. Radiotherapy is less utilised in this setting with uncertainty over deliverability and efficacy. Here, we present the details and outcomes of 20 patients treated with radiotherapy, with or without systemic therapy, for melanoma adrenal metastasis in a single institute. Twenty patients were identified from radiation treatment and medical records from between 2015 and 2019 at our institution. Three patients had bilateral radiotherapy treatments and therefore 23 adrenal lesions were analysed. Demographics, indications for treatment, radiotherapy methodology and outcomes were recorded. Outcomes were based on serial 18F FDG PET/computerized tomography scans reporting using the PERCIST criteria. The most common indication for radiotherapy was oligo-progressive disease (70%) followed by symptom palliation. Eight (35%) of the treatments were delivered by stereotactic ablative body radiotherapy. Twelve (60%) patients had concurrent immunotherapy. Twenty of twenty-three (87%) adrenal lesions had an initial response to treatment with 12 (60%) maintaining local control until death or end of follow-up. Median adrenal-specific progression-free survival was 13 months. Four patients (17%) required salvage adrenalectomy. Symptom palliation was achieved in the majority of patients for which it was indicated and there were no grade three toxicities. The median time from radiotherapy to change of immunotherapy treatment was 4 months. Radiotherapy for melanoma adrenal metastasis is effective and deliverable. With the majority of patients achieving a palliative and clinically relevant durable response, adrenalectomy can be reserved as a salvage option.

Pragmatic use of short-course radiotherapy, chemotherapy and surgery for stage IV rectal cancer with locally advanced or symptomatic primary tumours.

INTRODUCTION: We assessed management of patients with de novo metastatic rectal cancer, referred for radiotherapy to the rectum, who were candidates for short-course radiotherapy (SCRT) and chemotherapy, followed by resection of all disease. We assessed surgical outcomes, overall survival (OS) and progression-free survival (PFS). METHODS: Retrospective review of patients meeting criteria: (i) treatment with SCRT to rectum; (ii) locally advanced primary rectal cancer; and (iii) resectable distant metastases at diagnosis. Data were collected from charts, correspondence and electronic patient records. OS and PFS were calculated using the Kaplan-Meier method. RESULTS: Between 2016 and 2020, 48 patients with stage IV rectal cancer at diagnosis were treated with SCRT. Only 15 patients (31%) had resectable metastatic disease and were intended for SCRT (25 Gy/5#), then chemotherapy, followed by resection of all sites of disease and are included in our study. 12 of the 15 surgical candidates (80%) had rectal surgery as planned, and 11 of the 15 (73%) had resection of the rectal primary and all metastatic disease. One patient had a pathological complete response (pCR), and 50% of surgical patients had a Mandard TRG of 1 or 2. Median PFS and OS for the 15 surgical candidates were 12.6 and 25.2 months, respectively, with a median FU of 21.2 months. CONCLUSION: For this cohort of patients, our treatment paradigm is pragmatic and results in excellent pathological response. However, the effectiveness of this approach should be the subject of future prospective studies.

Stereotactic radiosurgery to surgical cavity post resection of brain metastases: Local recurrence and overall survival rates. A single-centre experience.

INTRODUCTION: We reviewed local control (LC) and overall survival (OS) post intracranial SRS to cavity post resection of brain metastases at one institution, and factors affecting LC. METHODS: A retrospective review was conducted of adjuvant SRS at one institution from 2013 to 2016. Patient records, treatment plans and diagnostic images were reviewed. Local failure was MRI defined. Categorical variables were analysed using chi-square and Fisher's exact tests. Continuous variables were analysed using Mann-Whitney tests. The Kaplan-Meier method was used to estimate survival times and the log-rank test was used to compare differences in survival. RESULTS: Forty-seven patients with 48 cavities were treated with SRS post operatively. LC rate was 69%, and the distant intracranial failure rate was 47% for entirety of the follow-up period. The 12-month freedom from local recurrence (FFLR) was 77% (63-91%). Median OS (95% CI) was 22.7 (14.6-30.8) months. Patients with a single metastasis had longer FFLR (30.1 vs 14.4 months; P = 0.014). Median interval from surgery to SRS was 6.3 weeks. Patients with interval >7 weeks had increased local recurrence (LR) (62%) than <7 weeks (37%), P = 0.025. Patients with a margin < 2 mm were more likely to experience LR (48%) than those with margin equal to 2 mm (20%); this approached statistical significance (P = 0.063). The median follow-up for all patients was 15.4 months (2-41). CONCLUSIONS: We determined LC and OS post adjuvant SRS at our institution. Based on the findings of this retrospective review SRS should be given promptly post operatively with a 2 mm PTV margin.

Clinical review of treatment outcomes and patterns of failure with adjuvant radiotherapy in node-positive malignant melanoma.

INTRODUCTION: Adjuvant radiotherapy is proven to prevent lymph node field relapse after therapeutic lymphadenectomy for melanoma, but does not improve overall survival based on current data. There remains a high rate of distant relapse. This study reports patterns of failure in patients treated with adjuvant radiotherapy, looking at factors associated with distant metastasis and comparing this to recent literature. METHODS: This retrospective study included patients treated with adjuvant nodal irradiation after lymphadenectomy between June 2012 and March 2015. RESULTS: Twenty-one patients were treated during this period. Median follow-up was 13.5 months. There were no lymph node field recurrences. Distant metastasis (DM) rate was 48%. DM rate was significantly higher (P = 0.027) in patients with extracapsular extension (ECE) (71%) than those without ECE (0%). DM rate was higher in those with a maximum tumour size of >3 cm (71%) than those with tumour size <3 cm (30%) (P = 0.160). Number of nodes, BRAF status or nodal site did not correlate with rate of DM. The median time to DM was 16 weeks after completion of radiotherapy. CONCLUSION: Radiotherapy is well tolerated and effective in regional control. However, patients are at risk of early distant relapse, particularly those with ECE or large tumour size. There are currently no useful prognostic markers to differentiate the risk of regional versus distant recurrence, and the optimal treatment paradigm remains undefined. Research on adjuvant systemic therapies and abscopal effects of radiotherapy have shown improved management of distant metastasis; creating an even greater need for effective regional control strategies.

Are cars the new tobacco?

BACKGROUND: Public health must continually respond to new threats reflecting wider societal changes. Ecological public health recognizes the links between human health and global sustainability. We argue that these links are typified by the harms caused by dependence on private cars. METHODS: We present routine data and literature on the health impacts of private car use; the activities of the 'car lobby' and factors underpinning car dependence. We compare these with experience of tobacco. RESULTS: Private cars cause significant health harm. The impacts include physical inactivity, obesity, death and injury from crashes, cardio-respiratory disease from air pollution, noise, community severance and climate change. The car lobby resists measures that would restrict car use, using tactics similar to the tobacco industry. Decisions about location and design of neighbourhoods have created environments that reinforce and reflect car dependence. Car ownership and use has greatly increased in recent decades and there is little public support for measures that would reduce this. CONCLUSIONS: Car dependence is a potent example of an issue that ecological public health should address. The public health community should advocate strongly for effective policies that reduce car use and increase active travel.