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Introduction: The aim was to determine which immobilisation device improved inter‐fraction reproducibly of pelvic tilt and required the least pre‐treatment setup and planning interventions. Methods: Sixteen patients were retrospectively reviewed, eight immobilised using the BodyFIX system (BodyFIX®, Elekta, Stockholm, Sweden) and eight using the Butterfly Board (BB) (Bionix Radiation Therapy, Toledo, OH, USA). The daily pre‐treatment images were reviewed to assess setup variations between each patient and groups for pelvic tilt, pubic symphysis, sacral promontory and the fifth lumbar spine (L5). Results: Compared with the planning CT, pelvic tilt for most patients was within ±2° using the BodyFIX and ± 4° for the BB. The Butterfly Board had a slightly higher variance both for patient‐to‐patient (standard deviation of the systematic error) and day‐to‐day error (standard deviation of the random error). Variance in position between individual patients and the two stabilisation devices were minimal in the anterior–posterior (AP) and superior–inferior (SI) direction for the pubic symphysis, sacral promontory and L5 spine. Re‐imaged fractions due to pelvic tilt reduced by about half when BodyFIX was used (39.1% BB, 19.4% BodyFIX). One patient treated with the BB required a re‐scan for pelvic tilt. Three patients required a re‐scan for body contour variations (two using BodyFIX and one with the BB). Conclusions: BodyFIX resulted in a more accurate inter‐fraction setup and efficient treatment and is used as the standard stabilisation for gynaecological patients at our centre. It reduced the pelvic tilt variance and reduced the need for re‐imaging pre‐treatment by half. [ABSTRACT FROM AUTHOR]

Introduction: Aimed to develop a simple and robust volumetric modulated arc radiotherapy (VMAT) solution for comprehensive lymph node (CLN) breast cancer without increase in low‐dose wash. Methods: Forty CLN‐breast patient data sets were utilised to develop a knowledge‐based planning (KBP) VMAT model, which limits low‐dose wash using iterative learning and base‐tangential methods as benchmark. Another twenty data sets were employed to validate the model comparing KBP‐generated ipsilateral VMAT (ipsi‐VMAT) plans against the benchmarked hybrid (h)‐VMAT (departmental standard) and bowtie‐VMAT (published best practice) methods. Planning target volume (PTV), conformity/homogeneity index (CI/HI), organ‐at‐risk (OAR), remaining‐volume‐at‐risk (RVR) and blinded radiation oncologist (RO) plan preference were evaluated. Results: Ipsi‐ and bowtie‐VMAT plans were dosimetrically equivalent, achieving greater nodal target coverage (P < 0.05) compared to h‐VMAT with minor reduction in breast coverage. CI was enhanced for a small reduction in breast HI with improved dose sparing to ipsilateral‐lung and humeral head (P < 0.05) at immaterial expense to spinal cord. Significantly, low‐dose wash to OARs and RVR were comparable between all plan types demonstrating a simple VMAT class solution robust to patient‐specific anatomic variation can be applied to CLN breast without need for complex beam modification (hybrid plans, avoidance sectors or other). This result was supported by blinded RO review. Conclusions: A simple and robust ipsilateral VMAT class solution for CLN breast generated using iterative KBP modelling can achieve clinically acceptable target coverage and OAR sparing without unwanted increase in low‐dose wash associated with increased second malignancy risk. [ABSTRACT FROM AUTHOR]

Introduction: Until late 2018, standard of practice at the Northern Sydney Cancer Centre (NSCC) for breast and nodal treatment was a conformal mono‐isocentric technique. A planning study comparing an existing mono‐isocentric three‐dimensional conformal radiotherapy (3D‐CRT) planning technique to a hybrid intensity‐modulated radiotherapy (hIMRT) approach for the whole breast and supraclavicular fossa (SCF) region was undertaken with the aim to improve plan quality by improving dose conformity/homogeneity across target volumes and reducing hotspots outside the target. Methods: A cohort of 17 patients was retrospectively planned using the proposed hIMRT technique, keeping the same planning constraints as the original treated breast and SCF 3D‐CRT plan and normalising the 3D‐CRT plans to achieve minimum breast/SCF target coverage to compare organs at risk (OARs). Normal tissue index (NTI) and homogeneity index (HI) were compared for plan quality as well as for evaluating OARs. Results: The hIMRT technique showed statistically significant improvements in NTI and HI, as well as improvement in maximum brachial plexus and thyroid doses. There was a negligible increase in maximum oesophagus dose which could be improved if used in optimisation. Other OAR doses in the irradiated region were comparable to the 3D‐CRT plans, however maximum doses were reduced overall. Conclusion: The hIMRT planning technique maintained clinically acceptable doses to OARs and reduced normal tissue dose while maintaining equivalent dose coverage to breast and SCF planning target volumes with improved conformity and homogeneity. The reduction in maximum doses promotes a favourable toxicity profile, with potential benefit of improved long‐term cosmesis. [ABSTRACT FROM AUTHOR]

Introduction: To create and clinically validate knowledge‐based planning (KBP) models for gynaecologic (GYN) and rectal cancer patients. Assessment of ecologic generalisability and predictive validity of conventional planning versus single calculation KBP was reviewed against practical metrics of planning time (PT) and radiation oncologist plan preference. Method: Study cohorts were 34 and 42 consecutively treated GYN and rectal cancer patients dosimetrically archived within the centre's research databank. For model training, structures and dose distributions from 22 and 32 GYN and rectal volumetric‐modulated arc therapy (VMAT) plans were used in RapidPlan™. Prescription doses ranged from 45 to 60Gy in 25 fractions using a simultaneous integrated boost to 2–4 targets and up to 9 organ‐at‐risk volumes. For model validation, 12 GYN and 10 rectal were independent of the archive and a single pass KBP VMAT plan was created. Each plan was evaluated against the archived treated plan under blinded conditions for radiation oncologist preference using standard dosimetric quality parameters. Results: All 22 plans generated in the KBP validation cohort met pre‐set GYN and rectal cancer dosimetric quality metrics. Fifty per cent of GYN plans and eighty per cent of rectal plans were judged superior to the manually optimised plans. KBP reduced PT considerably for both tumour sites. Conclusion: Single pass KBP for GYN and rectal cancer patients produced clinically acceptable treatment plans which were non‐inferior to conventionally optimised plans in 14 of 22 cases. Efficiencies captured by KBP will have predictable impacts on institutional workflows and resource allocation to facilitate adaptive planning. [ABSTRACT FROM AUTHOR]

Introduction: This patterns of practice study was conducted on behalf of the RANZCR Breast Interest Group in order to document current radiotherapy practices for breast cancer in Australia and New Zealand. The survey identifies variations and highlights potential contentious aspects of radiotherapy management of breast cancer.Methods: A fifty-eight question survey was disseminated via the Survey Monkey digital platform to 388 Radiation Oncologists in Australia and New Zealand.Results: In total, 156 responses were received and collated. Areas of notable consensus among respondents included hypofractionation (77.3% of respondents would 'always' or 'sometimes' consider hypofractionation in the management of ductal carcinoma in-situ and 99.3% in early invasive breast cancer); margin status in early breast cancer (73.8% believe a clear inked margin is sufficient and does not require further surgery) and use of bolus in post-mastectomy radiotherapy (PMRT) (91.1% of participants use bolus in PMRT). Areas with a wider degree of variability amongst respondents included regional nodal irradiation and components of radiotherapy planning and delivery (examples include the technique used for delivery of boost and frequency of bolus application for PMRT).Conclusion: The results of these patterns of practice survey informs radiation oncologists in Australia and New Zealand of the current clinical practices being implemented by their peers. The survey identifies areas of consensus and contention, the latter of which may lead to a development of research trials and/or educational activities to address these areas of uncertainty. [ABSTRACT FROM AUTHOR]

Aim Breast conserving surgery and adjuvant radiotherapy has equivalent oncological outcomes to mastectomy and is the standard of care for treatment of early-stage invasive breast cancer. Auditing is an essential component of ongoing quality assurance and clinical governance. It also serves to identify patient and tumor factors that have prognostic and therapeutic implications. The aim of this paper is to report on the clinical audit of treatment outcomes for patients undergoing adjuvant radiation treatment for early breast cancer at the Northern Sydney Cancer Care Centre. Methods A total of 1252 patients with T1/2 breast cancer received adjuvant radiation treatment between January 2003 and December 2010. Medical records, including the departmental database, were reviewed to extract pathological, treatment, patient and clinical details. Results Median follow-up was 54 months (mean 56.4 months). Sixty-six (5.27%) patients died from breast cancer, and 27 (2.16%) patients died from other disease. Twenty-three (1.84%) patients were alive with metastatic disease, 7 (0.56%) patients were alive following ipsilateral breast tumor recurrence and 7 (0.56%) patients were alive with nodal recurrence. 9 (0.72%) patients were alive with contralateral breast cancer. Documented rates of late toxicity were low: 6.8% of patients had grade 1 late toxicity and 1.6% of patients had grade 2-3 late toxicity. Conclusion Our ipsilateral breast tumor recurrence rate of 0.56% is well within international standards, as is our toxicity rate. We propose that centralized data collection be implemented on a nation-wide level for breast cancer patients undergoing radiotherapy. Further research is planned to identify potential markers of radio-resistance, and allow tailoring of treatment technique to optimize oncological outcome. [ABSTRACT FROM AUTHOR]

Introduction We report on a retrospective dosimetric study, comparing 3D conformal radiotherapy ( 3DCRT) and hybrid intensity modulated radiotherapy ( hIMRT). We evaluated plans based on their planning target volume coverage, dose homogeneity, dose to organs at risk ( OARs) and exposure of normal tissue to radiation. The Homogeneity Index ( HI) was used to assess the dose homogeneity in the target region, and we describe a new index, the normal tissue index ( NTI), to assess the dose in the normal tissue inside the tangent treatment portal. Methods Plans were generated for 25 early-stage breast cancer patients, using a hIMRT technique. These were compared with the 3 DCRT plans of the treatment previously received by the patients. Plan quality was evaluated using the HI, NTI and dose to OARs. Results The hIMRT technique was significantly more homogenous than the 3 DCRT technique, while maintaining target coverage. The hIMRT technique was also superior at minimising the amount of tissue receiving D105% and above ( P < 0.0001). The ipsilateral lung and contralateral breast maximum were significantly lower in the hIMRT plans ( P < 0.05 and P < 0.005), but the 3 DCRT technique achieved a lower mean heart dose in left-sided breast cancer patients ( P < 0.05). Conclusion Hybrid intensity modulated radiotherapy plans achieved improved dose homogeneity compared to the 3 DCRT plans and superior outcome with regard to dose to normal tissues. We propose that the addition of both HI and NTI in evaluating the quality of intensity modulated radiotherapy ( IMRT) breast plans provides clinically relevant comparators which more accurately reflect the new paradigm of treatment goals and outcomes in the era of breast IMRT. [ABSTRACT FROM AUTHOR]

Introduction The clinical target volume ( CTV) for early stage breast cancer is difficult to clearly identify on planning computed tomography ( CT) scans. Surgical clips inserted around the tumour bed should help to identify the CTV, particularly if the seroma has been reabsorbed, and enable tracking of CTV changes over time. Methods A surgical clip-based CTV delineation protocol was introduced. CTV visibility and its post-operative shrinkage pattern were assessed. The subjects were 27 early stage breast cancer patients receiving post-operative radiotherapy alone and 15 receiving post-operative chemotherapy followed by radiotherapy. The radiotherapy alone ( RT/alone) group received a CT scan at median 25 days post-operatively ( CT1rt) and another at 40 Gy, median 68 days ( CT2rt). The chemotherapy/ RT group (chemo/ RT) received a CT scan at median 18 days post-operatively ( CT1ch), a planning CT scan at median 126 days ( CT2ch), and another at 40 Gy ( CT3ch). Results There was no significant difference ( P = 0.08) between the initial mean CTV for each cohort. The RT/alone cohort showed significant CTV volume reduction of 38.4% ( P = 0.01) at 40 Gy. The Chemo/ RT cohort had significantly reduced volumes between CT1ch: median 54 cm3 (4-118) and CT2ch: median 16 cm3, (2-99), ( P = 0.01), but no significant volume reduction thereafter. Conclusion Surgical clips enable localisation of the post-surgical seroma for radiotherapy targeting. Most seroma shrinkage occurs early, enabling CT treatment planning to take place at 7 weeks, which is within the 9 weeks recommended to limit disease recurrence. [ABSTRACT FROM AUTHOR]

Introduction: To create and clinically validate knowledge‐based planning (KBP) models for gynaecologic (GYN) and rectal cancer patients. Assessment of ecologic generalisability and predictive validity of conventional planning versus single calculation KBP was reviewed against practical metrics of planning time (PT) and radiation oncologist plan preference. Method: Study cohorts were 34 and 42 consecutively treated GYN and rectal cancer patients dosimetrically archived within the centre's research databank. For model training, structures and dose distributions from 22 and 32 GYN and rectal volumetric‐modulated arc therapy (VMAT) plans were used in RapidPlan™. Prescription doses ranged from 45 to 60Gy in 25 fractions using a simultaneous integrated boost to 2–4 targets and up to 9 organ‐at‐risk volumes. For model validation, 12 GYN and 10 rectal were independent of the archive and a single pass KBP VMAT plan was created. Each plan was evaluated against the archived treated plan under blinded conditions for radiation oncologist preference using standard dosimetric quality parameters. Results: All 22 plans generated in the KBP validation cohort met pre‐set GYN and rectal cancer dosimetric quality metrics. Fifty per cent of GYN plans and eighty per cent of rectal plans were judged superior to the manually optimised plans. KBP reduced PT considerably for both tumour sites. Conclusion: Single pass KBP for GYN and rectal cancer patients produced clinically acceptable treatment plans which were non‐inferior to conventionally optimised plans in 14 of 22 cases. Efficiencies captured by KBP will have predictable impacts on institutional workflows and resource allocation to facilitate adaptive planning. [ABSTRACT FROM AUTHOR]