Radiation therapy for deep periocular cancer treatments when protons are unavailable: is combining electrons and orthovoltage therapy beneficial?

Deep periocular cancers can be difficult to plan and treat with radiation, given the difficulties in apposing bolus to skin, and the proximity to the retina and other optic structures. We sought to compare the combination of electrons and orthovoltage therapy (OBE) with existing modalities for these lesions. Four cases-a retro-orbital melanoma (Case 1) and basal cell carcinomas, extending across the eyelid (Case 2) or along the medial canthus (Cases 3-4)-were selected for comparison. In each case, radiotherapy plans for electron only, 70% electron and 30% orthovoltage (OBE), volumetric-modulated arc therapy (VMAT), conformal arc, and protons were compared. Dose-volume histograms for planning target volume coverage and selected organs at risk (OARs) were then calculated. The V90% coverage of the planning target volume was >98% for electrons, VMAT, conformal arc and proton plans and 90.2% and 89.5% in OBE plans for Cases 2 and 3, respectively. The retinal V80% was >98% in electron, VMAT and proton plans and 79.4%; and 87.1% in OBE and conformal arcs for Case 2 and 91.3%, 36.4%, 56.9%, 52.4% and 43.7% for Case 3 in electrons, OBE, VMAT, conformal arc and proton plans, respectively. Protons provided superior coverage, homogeneity and OAR sparing, compared with all other modalities. However, given its simplicity and widespread availability, OBE is a potential alternative treatment option for moderately deep lesions where bolus placement is difficult.

Survival was Significantly Better with Surgical/Medical/Radiation Co-interventions in a Single-Institution Practice Audit of Frameless Stereotactic Radiosurgery.

PURPOSE: To audit outcomes after introducing frameless stereotactic radiosurgery (SRS) for brain metastases, including co-interventions: neurosurgery, systemic therapy, and whole brain radiotherapy (WBRT). We report median overall survival (MS), local failure, and distant brain failure. We hypothesized patients treated with SRS would have clinically meaningful improved MS compared with historic institutional values. We further hypothesized that patients treated with co-interventions would have clinically meaningful improved MS compared with patients treated with SRS alone. METHODS: One hundred twenty patients (N = 120) with limited intracranial disease underwent 130 frameless SRS sessions from April 2010 to May 2013. Median follow-up was 11 months. MS was measured from brain metastases diagnosis, local failure, and distant brain failure from the time of first SRS. RESULTS: Practice pattern during the first year of the study favored upfront WBRT (79%) over SRS (21%) while upfront SRS (45%) was almost as common as upfront WBRT (55%) in the last year of the study. MS was 18 months; 37% received SRS alone as initial radiotherapy (MS 12 months); 63% received WBRT prior to SRS (MS 19 months); 50% received systemic therapy post-SRS (MS 21 months); and 26% had tumor resection then SRS to the surgical cavity (MS 42 months). Local failure occurred in 10% of lesions and radio-necrosis occurred in 4%. Differences in distant brain failure among patients treated with upfront SRS (40% rate), WBRT followed by SRS (33% rate) or systemic therapy post-SRS (37% rate) were not statistically significant. CONCLUSION: Frameless SRS effectively treats surgical cavities, persistent tumors post-WBRT, and can be used as an upfront treatment of brain metastases. Surgery, systemic therapy, and WBRT are associated with longer MS. Patients can live for years while receiving multiple therapies. Systemic therapy for patients with brain metastases is increasingly common, palliative care occurs earlier and improves survival, and WBRT use is not routine. Modern series sometimes produce unexpectedly good results. Classification and treatment protocols are evolving. This practice audit is note-worthy for (i) high median overall survival, (ii) systemic therapy after radiosurgery for patients with tumors treated by radiosurgery, (iii) distant brain failure not significantly related to WBRT, and (iv) neurosurgery, systemic therapy, and WBRT are independently associated with improved MS.

The effect of contouring variability on dosimetric parameters for brain metastases treated with stereotactic radiosurgery.

PURPOSE: To quantify the effect of contouring variation on stereotactic radiosurgery plan quality metrics for brain metastases. METHODS AND MATERIALS: Fourteen metastases, each contoured by 8 physicians, formed the basis of this study. A template-based dynamic conformal 5-arc dose distribution was developed for each of the 112 contours, and each dose distribution was applied to the 7 other contours in each patient set. Radiation Therapy Oncology Group (RTOG) plan quality metrics and the Paddick conformity index were calculated for each of the 896 combinations of dose distributions and contours. RESULTS: The ratio of largest to smallest contour volume for each metastasis varied from 1.25 to 4.47, with a median value of 1.68 (n=8). The median absolute difference in RTOG conformity index between the value for the reference contour and the values for the alternative contours was 0.35. The variation of the range of conformity index for all contours for a given tumor varied with the tumor size. CONCLUSIONS: The high degree of interobserver contouring variation strongly suggests that peer review or consultation should be adopted to standardize tumor volume prescription. Observer confidence was not reflected in contouring consistency. The impact of contouring variability on plan quality metrics, used as criteria for clinical trial protocol compliance, was such that the category of compliance was robust to interobserver effects only 70% of the time.

Managing brain metastases patients with and without radiotherapy: initial lessonsfrom a team-based consult service through a multidisciplinary integrated palliative oncology clinic.

PURPOSE: A new ambulatory consultative clinic with integrated assessments by palliative care, radiation oncology, and allied health professionals was introduced to (1) assess patients with brain metastases at a regional comprehensive cancer center and (2) inform and guide patients on management strategies, including palliative radiotherapy, symptom control, and end-of-life care issues. We conducted a quality assurance study to inform clinical program development. METHODS: Between January 2011 and May 2012, 100 consecutive brain metastases patients referred and assessed through a multidisciplinary clinic were evaluated for baseline characteristics, radiotherapy use, and supportive care decisions. Overall survival was examined by known prognostic groups. Proportion of patients receiving end-of-life radiotherapy (death within 30 and 14 days of brain radiotherapy) was used as a quality metric. RESULTS: The median age was 65 years, with non-small cell lung cancer (n = 38) and breast cancer (n = 23) being the most common primary cancers. At least 57 patients were engaged in advance care planning discussions at first consult visit. In total, 75 patients eventually underwent brain radiotherapy, whereas 25 did not. The most common reasons for nonradiotherapy management were patient preference and rapid clinical deterioration. Overall survival for prognostic subgroups was consistent with literature reports. End-of-life brain radiotherapy was observed in 9 % (death within 30 days) and 1 % (within 14 days) of treated patients. CONCLUSIONS: By integrating palliative care expertise to address the complex needs of patients with newly diagnosed brain metastases, end-of-life radiotherapy use appears acceptable and improved over historical rates at our institution. An appreciable proportion of patients are not suitable for palliative brain radiotherapy or opt against this treatment option, but the team approach involving nurses, palliative care experts, allied health, and clinical oncologists facilitates patient-centered decision making and transition to end-of-life care.

Image-Guided Treatment of Fractionated Stereotactic Radiotherapy Patients: A Quantitative Analysis of Pre- and Post-Treatment Orthogonal kV Images of Patients Immobilized with Thermoplastic Masks.

OBJECTIVES: To measure setup and intrafraction variability for intracranial targets during treatment of patients immobilized with a Brainlab, Inc. thermoplastic head mask using ExacTrac© imaging on the treatment unit. PATIENTS AND METHODS: Between November 2007 and June 2008, 12 patients were treated with cranial fractionated stereotactic radiation therapy for 25-28 fractions. Patient offset was calculated by the ExacTrac© algorithm from the planning computed tomography and orthogonal kV images taken at the time of treatment. Shifts of the patient position were done when the initial offset was greater than 1.5 mm. If a shift was made, post-shift images were acquired before treatment. Images were also acquired post-treatment to determine intrafraction movement. RESULTS: A total of 849 pairs of images were obtained. The averaged results of all 12 patients were: setup offset was 1.98 mm, treatment offset was 0.57 mm, and post-treatment offset was 0.66 mm. Of 303 fractions treated, 30 fractions had a post-treatment offset greater than 1.5 mm. CONCLUSION: Quantitative analysis of the data set including variability in patient setup and intrafraction motion shows patient position can be reproduced within 1.0 mm using Brainlab thermoplastic head mask systems using the ExacTrac© system.

Chest wall pain and rib fracture after stereotactic radiotherapy for peripheral non-small cell lung cancer.

Stereotactic body radiotherapy is an emerging treatment option for peripheral non-small cell lung cancer in medically inoperable patients. With high dose per fraction radiotherapy, late side effects are of possible concern. In our initial cohort of 42 patients treated with 54 to 60 Gy in three fractions, nine patients have rib fracture. The median dose to rib fracture sites was 46 to 50 Gy, depending on the method of dose calculation. We describe a typical case of poststereotactic radiotherapy rib fracture and present dosimetric analysis of patients with rib fracture.

Prospective comparison of computed tomography and magnetic resonance imaging for liver cancer delineation using deformable image registration.

PURPOSE: The aim of this study was to compare magnetic resonance imaging (MRI) with computed tomography (CT) for liver cancer tumor definition for high-precision radiotherapy planning. METHODS AND MATERIALS: Diagnostic quality MRI scans and triphasic CT scans, with the liver immobilized in exhale, were obtained at the time of radiation planning for 26 patients with unresectable liver metastases (n = 8), hepatocellular carcinoma (n = 10), and cholangiocarcinoma (n = 8). On the CT and MRI series best demonstrating the tumor, the liver and gross tumor volumes (GTVs) were contoured, and intrahepatic anatomic reference points were identified. Deformable registration was used to register the liver from the CT with that from the MRI. RESULTS: A difference in the number of tumor foci was seen on CT vs. MRI in 5 patients with hepatocellular carcinoma: MRI showed more foci in 3 patients, CT in 2. After deformable registration of the livers, the population median of the average distance between the CT tumor surface and MRI tumor surface was 3.7 mm (2.2-21.3 mm). The median percentage of tumor surface area that differed by > or = 5 mm was 26% (1-86%). Median percentage concordance volumes were 81% (77-86%) in metastases, 77% (60-88%) in hepatocellular carcinoma and 64% (25-85%) in cholangiocarcinoma. CONCLUSION: Differences between MRI-defined liver cancer GTVs and CT-defined GTVs can be substantial and are more common in primary liver cancer.