Impact of SSTR PET on Inter-Observer Variability of Target Delineation of Meningioma and the Possibility of Using Threshold-Based Segmentations in Radiation Oncology.

Aim: The aim of this study was to assess the effects of including somatostatin receptor agonist (SSTR) PET imaging in meningioma radiotherapy planning by means of changes in inter-observer variability (IOV). Further, the possibility of using threshold-based delineation approaches for semiautomatic tumor volume definition was assessed. Patients and Methods: Sixteen patients with meningioma undergoing fractionated radiotherapy were delineated by five radiation oncologists. IOV was calculated by comparing each delineation to a consensus delineation, based on the simultaneous truth and performance level estimation (STAPLE) algorithm. The consensus delineation was used to adapt a threshold-based delineation, based on a maximization of the mean Dice coefficient. To test the threshold-based approach, seven patients with SSTR-positive meningioma were additionally evaluated as a validation group. Results: The average Dice coefficients for delineations based on MRI alone was 0.84 ± 0.12. For delineation based on MRI + PET, a significantly higher dice coefficient of 0.87 ± 0.08 was found (p < 0.001). The Hausdorff distance decreased from 10.96 ± 11.98 mm to 8.83 ± 12.21 mm (p < 0.001) when adding PET for the lesion delineation. The best threshold value for a threshold-based delineation was found to be 14.0% of the SUVmax, with an average Dice coefficient of 0.50 ± 0.19 compared to the consensus delineation. In the validation cohort, a Dice coefficient of 0.56 ± 0.29 and a Hausdorff coefficient of 27.15 ± 21.54 mm were found for the threshold-based approach. Conclusions: SSTR-PET added to standard imaging with CT and MRI reduces the IOV in radiotherapy planning for patients with meningioma. When using a threshold-based approach for PET-based delineation of meningioma, a relatively low threshold of 14.0% of the SUVmax was found to provide the best agreement with a consensus delineation.

Feasibility of arm-draining lymph node-sparing radiotherapy of breast cancer: A pilot planning study.

INTRODUCTION: Lymphoedema following axillary radiotherapy for breast cancer causes significant morbidity. Our goal was to evaluate the feasibility of sparing the lymph node that drains the arm's lymphatics (ARM node) while achieving standard dose constraints for whole breast and comprehensive lymph node irradiation. METHODS: Six patients underwent lymphoscintigraphy and SPECT CT to identify the breast sentinel node (SN) and ARM node. The ARM node was contoured on the SPECT CT and deformably registered to the radiotherapy treatment planning CT. Radiotherapy plans (50 Gy in 25 fractions) with VMAT technique were generated, with the aim to spare the ARM node (Mean dose <25 Gy) and achieve adequate coverage to the remaining axilla. The plan required the breast SN site (clip + 10 mm surrounding the clip) to achieve D98% > 47.5 Gy, and axillary nodal CTV excluding ARM node to achieve D90% > 45 Gy. RESULTS: In one patient, the ARM node was within the volume of breast SN site and sparing was not possible. For the remaining 5 patients, an ARM node-sparing plan could be successfully generated; the mean dose to the ARM node ranged from 11.2 to 23.1 Gy (median 13.8 Gy). In these 5 subjects, D90% > 45 Gy of axillary nodal CTV (range, 44.9-48.5 Gy, median 46.2 Gy) and D98% > 47.5 Gy of breast SN site were achieved. CONCLUSION: In this planning study, ARM node-sparing VMAT of the breast and lymph nodes was feasible, while maintaining adequate dosimetric coverage. However, in some individuals, localization of the ARM node in close proximity to breast SN site precluded the generation of an ARM node-sparing treatment plan.

Management of melanoma brain metastases: Evidence-based clinical practice guidelines by Cancer Council Australia.

INTRODUCTION: The brain is a common site of metastatic disease for patients with advanced melanoma. Brain metastasis portends a poor prognosis, often causing deterioration in neurological function and quality of life, and leading to neurological death. Treatment approaches including surgery, radiotherapy and systemic therapy can lead to better control of this problem. Therefore, appropriate guidelines for the management of melanoma brain metastases need to be established, with regular updating when new treatment options become available. METHODS: A multidisciplinary working party established by Cancer Council Australia has produced up-to-date, evidence-based clinical practice guidelines for the management of melanoma. After selecting key clinical questions, a comprehensive literature search for relevant studies was conducted, followed by systematic review of those studies. Data were summarised and the evidence was assessed, leading to the development of recommendations. MAIN RECOMMENDATIONS: Symptomatic lesions are best treated with surgery, when possible; this provides safe and effective local control. For patients with single or a small number of asymptomatic brain metastases, stereotactic radiotherapy is recommended, but in asymptomatic patients who have not previously received systemic treatment, drug therapy can be considered as a first-line treatment option. Whole brain radiotherapy may provide palliative benefits in patients with multiple brain metastases. Whenever possible, melanoma patients with brain metastases should be managed by a multidisciplinary team of melanoma specialists that considers the optimal combination and sequencing of surgery, radiotherapy and systemic therapy.

Postoperative radiotherapy for prostate cancer : Morbidity of local-only or local-plus-pelvic radiotherapy.

PURPOSE: The aim of this work was to characterise actuarial incidence and prevalence of early and late side effects of local versus pelvic three-dimensional conformal postoperative radiotherapy for prostate cancer. MATERIALS AND METHODS: Based on a risk-adapted protocol, 575 patients received either local (n = 447) or local-plus-pelvic (n = 128) radiotherapy. Gastrointestinal (GI) and genitourinary (GU) side effects (≥grade 2 RTOG/EORTC criteria) were prospectively assessed. Maximum morbidity, actuarial incidence rate, and prevalence rates were compared between the two groups. RESULTS: For local radiotherapy, median follow-up was 68 months, and the mean dose was 66.7 Gy. In pelvic radiotherapy, the median follow-up was 49 months, and the mean local and pelvic doses were 66.9 and 48.3 Gy respectively. Early GI side effects ≥ G2 were detected in 26% and 42% of patients respectively (p < 0.001). Late GI adverse events were detected in 14% in both groups (p = 0.77). The 5­year actuarial incidence rates were 14% and 14%, while the prevalence rates were 2% and 0% respectively. Early GU ≥ G2 side effects were detected in 15% and 16% (p = 0.96), while late GU morbidity was detected in 18% and 24% (p = 0.001). The 5­year actuarial incidence rates were 16% and 35% (p = 0.001), while the respective prevalence rates were 6% and 8%. CONCLUSIONS: Despite the low prevalence of side effects, postoperative pelvic radiotherapy results in significant increases in the actuarial incidence of early GI and late GU morbidity using a conventional 4­field box radiotherapy technique. Advanced treatment techniques like intensity-modulated radiotherapy (IMRT) or volumetric modulated arc radiotherapy (VMAT) should therefore be considered in pelvic radiotherapy to potentially reduce these side effects.

Vienna Summer School on Oncology: how to teach clinical decision making in a multidisciplinary environment.

BACKGROUND: Clinical decision making in oncology is based on both inter- and multidisciplinary approach. Hence teaching future doctors involved in oncology or general health practice is crucial. The aim of the Vienna Summer School on Oncology (VSSO) as an international, integrated, undergraduate oncology course is to teach medical students interdisciplinary team communication and application of treatment concepts/algorithms in a multidisciplinary setting. METHOD: The teaching is based on an inter- and multidisciplinary faculty and a multimodal education approach to address different learning styles. The participants rated their satisfaction of the program voluntarily after finishing the course according to a grading scale from one (not good) to five (very good). The learning success was assessed by a compulsory pre-VSSO and post-VSSO single choice questionnaire. RESULTS: Program organisation was rated with a mean score of 4.47 out of 5.0 (SD 0.51), composition of the program and range of topics with a mean score of 4.68 (SD 0.58) and all teachers with a mean score of 4.36 (SD 0.40) points. Student evaluation at the beginning and end of the program indicated significant knowledge acquisition -i.e., general aspects of cancer: median 8.75 points (IQR 7.5-9.4) vs.10.0 points (IQR 9.4-10.0) p = 0.005; specific aspects of cancer: median 4.87 points (IQR 3.33-5.71) vs. 8.72 points (IQR 6.78-9.49) p ≤ 0.001, respectively. CONCLUSION: Even though the participants represent a selection of students with special interest in cancer, the results of the VSSO indicate the benefit of an inter- and multidisciplinary teaching approach within an oncology module.