PURPOSE:This study aims to compare the dosimetric impact of incorporating systematic and random setup uncertainties in the robust optimization of head and neck cancer (HNC) Intensity Modulated Proton Therapy (IMPT) plans. METHODS:Bilateral HNC patients (n = 10) previously treated with conventional photon therapy at our institution were included. Both systematic and random setup uncertainties were incorporated into the robust optimization process of IMPT planning. Dosimetric comparisons were made between plans optimized with systematic (IMPT-S) versus random (IMPT-R) setup uncertainties, assessing both the clinical target volume (CTVs) and organs at risk (OARs) across various dosimetric metrics. Both plans applied a fixed range uncertainty of ± 3 % and a maximum setup uncertainty of ± 3 mm. RESULTS:Both IMPT-S and IMPT-R plans achieved similar target coverage, meeting robustness criteria for CTVs. On average, the D95% voxel-wise min to the high-risk CTV (CTV_HR) was slightly higher in IMPT-S plans by 1.78 ± 0.72 % compared to IMPT-R plans. However, IMPT-R plans provided better OAR sparing, which was evident in both nominal and voxel-wise maximum values. While random setup errors in robust optimization improved OAR sparing, the clinical impact may be minimal where OAR doses are already well below tolerance levels. CONCLUSION:Both IMPT-S and IMPT-R techniques met the robustness criteria for CTVs in HNC IMPT planning. Incorporating random setup uncertainties in robust optimization improves OAR sparing compared to systematic setup uncertainties. Further research is needed to explore the broader applicability of random setup errors and to integrate random uncertainties in robustness evaluations for a more comprehensive assessment of treatment plans.

PURPOSE:A novel proton beam delivery method known as DynamicARC spot scanning has been introduced. The current study aims to determine whether the partial proton arc technique, in conjunction with DynamicARC pencil beam scanning (PBS), can meet clinical acceptance criteria for bilateral head and neck cancer (HNC) and provide an alternative to full proton arc and traditional intensity-modulated proton therapy (IMPT). METHOD:The study retrospectively included anonymized CT datasets from ten patients with bilateral HNC, all of whom had previously received photon treatment. The clinical target volumes (CTV) were categorized into three levels: CTV_7000, CTV_5950, and CTV_5600. IMPT plans included three beams, whereas DynamicARC plans included dual-partial-arcs (DPA), single-partial-arc (SPA), and single-full-arc (SFA). All plans underwent robust optimization considering setup (± 3 mm) and range (± 3%) uncertainties applied to the CTVs. DynamicARC plans were evaluated against the NRG-HN009 criteria and IMPT plans using various metrics. RESULTS:All four techniques-IMPT, DPA, SPA, and SFA-demonstrated substantial compliance with NRG-HN009 dosimetric criteria. DynamicARC produced superior dose conformity, lower hotspot, and improved homogeneity for high-risk CTV compared to IMPT, with comparable performance for intermediate- and low-risk CTVs. DynamicARC reduced the Dmean to the parotid glands by average differences of 14.5%-22.1% and to the oral cavity by an average difference of 15.75% compared to IMPT. DPA and SPA techniques achieved reductions in total integral dose of 3.7%-5.7% relative to IMPT. Overall, DPA yielded dosimetric results comparable to those of SFA while offering more conformal dose distributions and slightly better organ at risk sparing than SPA. CONCLUSION:On the ProteusOne with a partial gantry system, DPA and SPA, in conjunction with DynamicARC PBS protons, provided clear dosimetric advantages over three-field IMPT. Future clinical implementation and further research into optimizing DynamicARC protocols are warranted to fully realize the benefits of these techniques in clinical settings.

Advances in radiotherapy (RT) technologies permit significant decreases in the dose delivered to organs at risk (OARs) for patients with esophageal cancer (EC). Novel RT modalities such as proton beam therapy (PBT) and magnetic resonance-guided radiotherapy (MRgRT), as well as motion management techniques including breath hold (BH) are expected to further improve the therapeutic ratio. However, to our knowledge, the dosimetric benefits of PBT vs MRgRT vs volumetric-modulated arc therapy (VMAT) have not been directly compared for EC. We performed a retrospective in silico evaluation using the images and datasets of nine distal EC patients who were treated at our institution with a 0.35-Tesla MR linac to 50.4 Gy in 28 fractions in mid-inspiration BH (BH-MRgRT). Comparison free-breathing (FB) intensity-modulated PBT (FB-IMPT) and FB-VMAT plans were retrospectively created using the same prescription dose, target volume coverage goals, and OAR constraints. A 5 mm setup margin was used for all plans. BH-IMPT and BH-VMAT plans were not evaluated as they would not reflect our institutional practice. Planners were blinded to the results of the treatment plans created using different radiation modalities. The primary objective was to compare plan quality, target volume coverage, and OAR doses. All treatment plans met pre-defined target volume coverage and OAR constraints. The median conformity and homogeneity indices between FB-IMPT, BH-MRgRT and FB-VMAT were 1.13, 1.25, and 1.43 (PITV) and 1.04, 1.15, 1.04 (HI), respectively. For FB-IMPT, BH-MRgRT and FB-VMAT the median heart dose metrics were 52.8, 79.3, 146.8 (V30Gy, cc), 35.5, 43.8, 77.5 (V40Gy, cc), 16.9, 16.9, 32.5 (V50Gy, cc) and 6.5, 14.9, 17.3 (mean, Gy), respectively. Lung dose metrics were 8.6, 7.9, 18.5 (V20Gy, %), and 4.3, 6.3, 11.2 (mean, Gy), respectively. The mean liver dose (Gy) was 6.5, 19.6, 22.2 respectively. Both FB-IMPT and BH-MRgRT achieve substantial reductions in heart, lung, and liver dose compared to FB-VMAT. We plan to evaluate dosimetric outcomes across these RT modalities assuming consistent use of BH.

Background: In current clinical practice, intensity-modulated proton therapy (IMPT) head and neck cancer (HNC) plans are generated using a constant relative biological effectiveness (cRBE) of 1.1. The primary goal of this study was to explore the dosimetric impact of proton range uncertainties on RBE-weighted dose (RWD) distributions using a variable RBE (vRBE) model in the context of bilateral HNC IMPT plans. Methods: The current study included the computed tomography (CT) datasets of ten bilateral HNC patients who had undergone photon therapy. Each patient’s plan was generated using three IMPT beams to deliver doses to the CTV_High and CTV_Low for doses of 70 Gy(RBE) and 54 Gy(RBE), respectively, in 35 fractions through a simultaneous integrated boost (SIB) technique. Each nominal plan calculated with a cRBE of 1.1 was subjected to the range uncertainties of ±3%. The McNamara vRBE model was used for RWD calculations. For each patient, the differences in dosimetric metrices between the RWD and nominal dose distributions were compared. Results: The constrictor muscles, oral cavity, parotids, larynx, thyroid, and esophagus showed average differences in mean dose (Dmean) values up to 6.91 Gy(RBE), indicating the impact of proton range uncertainties on RWD distributions. Similarly, the brachial plexus, brain, brainstem, spinal cord, and mandible showed varying degrees of the average differences in maximum dose (Dmax) values (2.78–10.75 Gy(RBE)). The Dmean and Dmax to the CTV from RWD distributions were within ±2% of the dosimetric results in nominal plans. Conclusion: The consistent trend of higher mean and maximum doses to the OARs with the McNamara vRBE model compared to cRBE model highlighted the need for consideration of proton range uncertainties while evaluating OAR doses in bilateral HNC IMPT plans.

AbstractThe multi‐leaf collimator (MLC)‐equipped CyberKnife® M6 radiosurgery system (CKM6) (Accuray Inc., Sunnyvale, CA) has been increasingly employed for stereotactic radiosurgery (SRS) to treat relatively small lesions. However, achieving an accurate dose distribution in such cases is usually challenging due to the combination of numerous small fields ≤ (30 × 30) mm2. In this study, we developed a new Monte Carlo (MC) dose model for the CKM6 system using the EGSnrc to investigate dose variations in the small fields. The dose model was verified for the static MLC fields ranging from (53.8 × 53.9) to (7.6 × 7.7) mm2 at 800 mm source to axis distance in a water phantom, based on the computed doses of Accuray Precision® (Accuray Inc.) treatment planning system (TPS). We achieved a statistical uncertainty of ≤4% by simulating 30–50 million incident particles/histories. Then, the treatment plans were created for the same fields in the TPS, and the corresponding measurements were performed with MapCHECK2 (Sun Nuclear Corporation), a standard device for patient‐specific quality assurance (PSQA). Results of the MC simulations, TPS, and MapCHECK2 measurements were inter‐compared. An overall difference in dosimetric parameters such as profiles, tissue maximum ratio (TMR), and output factors (OF) between the MC simulations and the TPS results was found ≤3% for (53.8 × 53.9–15.4 × 15.4) mm2 MLC fields, and it rose to 4.5% for the smallest (7.6 mm × 7.7 mm) MLC field. The MapCHECK2 results showed a deviation ranging from –1.5% to + 4.5% compared to the TPS results, whereas the deviation was within ±2.5% compared with the MC results. Overall, our MC dose model for the CKM6 system showed better agreement with measurements and it could serve as a secondary dose verification tool for the patient‐specific QA in small fields.

PURPOSE:Keratinocyte carcinomas are amenable to many treatments, including radiation therapy (RT). Electronic skin surface brachytherapy (ESSB) enables the precise delivery of radiation without radioisotopes. In this prospective multicenter clinical trial, we characterized early outcomes of ESSB prospectively through both patient- and clinician-reported measures. To corroborate the cosmesis observations, we also assessed patient-reported quality of life (QoL) and adverse events. METHODS AND MATERIALS:Patients ≥60 years old with stage T1N0M0 keratinocyte carcinoma were treated with ESSB. At 2-, 6-, and 12-weeks post-treatment, cosmesis from ESSB was assessed by both the patient and a clinician study investigator as either "good," "fair," or "bad." The Skindex-16 and the Skin Cancer Index (SCI) were used to assess patient QoL before and after treatment. Adverse events were assessed using the Common Toxicity Criteria for Adverse Events, version 4.0. RESULTS:Cosmesis and QoL were collected at 97% (99/102) of possible patient follow-up times. By 12 weeks post-treatment, 93.9% (31/33) of patient-reported and 96.9% (31/32) of clinician-reported cosmesis outcomes were "good." Compared with baseline, total Skindex-16 score significantly deteriorated at 2 weeks post-treatment (10.5 vs 24.5, P <.001), but significantly improved at 6 weeks (10.5 vs 4.7, P = .014) and 12 weeks (10.5 vs 2.1, P = .001) post-treatment. The total SCI score significantly improved from baseline to 6 weeks (78.4 vs 89.0, P = .001) post-treatment. The most frequent adverse events were radiation dermatitis, skin pain, and pruritus. All adverse events resolved to Grade ≤1 by 12 weeks post-treatment. CONCLUSIONS:This prospective, multicenter study demonstrated that ESSB is associated with a high rate of "good" early patient-reported cosmesis and increasing QoL and satisfaction with time. Validated assessments demonstrated a significant improvement in quality of life and resolution of moderate early adverse events by 6 to 12 weeks after treatment and corroborate the observation of favorable cosmesis.

Respiratory tracking using a single fiducial has been considered a method completely lacking of target rotation information. However, the uncertainty of the model is based on the intensity agreement between two sets of 21x21pixel arrays of the position-tracking image and the corresponding DRR’s generated from the planning system . This study is to explore the relationship between target rotation and the uncertainty of a single fiducial-based system. A respiratory motion phantom was used to simulate a lung tumor target. In test “A”, a 64 mm mini-ball cube with three 5x1 mm cylindrical fiducials was inserted to the lung module. One fiducial was used for the model. In the test “B”, a single 0.4x20mm fiducial, folded to about 3x5mm spherical cluster, was imbedded in the lung module. During treatment, 2 cm longitudinal, linear lung tumor motion was simulated, combined with different, fixed, yaw rotational angles between 0 – 60°. Rotational boundary corrections were automatically disabled while the tracking model was obtained. The uncertainties of the final tracking models displayed on the treatment console were recorded by averaging 15 images' uncertainties taken during module's longitudinal motion. Yaw angles from 0-60° in 10-degree intervals respective to initial simulation image were used. The test was repeated with each phantom twice. An End-to-End test was performed. Motion of phantom with yaw rotation results in a significant increase of the single fiducial-based tracking uncertainty for both types of fiducials, the cylindrical and cluster. (Table 1). Both uncertainties significantly increase from 0-60°. The cylindrical fiducial uncertainty ranged from 18% to 58% from 0-60°.The clustered fiducial uncertainty ranged from 17% to 26% from 0-60°. Cylindrical fiducial uncertainty is higher than that from the spherical fiducial for all yaw angles. Greater than 1mm treatment inaccuracy was indicated per its End-to End film dosimetry test when the uncertainty exceeded the default value (40%).Abstract TU_26_3147; Table 1Uncertainty (%) as function of yaw angle for two different fiducials. Ucyl - cylindrical Uncertainty Uclu - Spherical Cluster Uncertainty Scyl -Cylindrical Std dev Sclu - Spherical ClusterYaw Angle°Ucyl%Uclu%scyl%sclu%018.517.00.311.011019.617.70.820.512023.719.20.670.743030.821.80.640.604039.523.90.460.474544.624.60.480.805049.724.90.380.596057.725.70.350.57 Open table in a new tab This investigation suggests that the uncertainty of the model can directly imply the degree of yaw rotation of the target when a single unsymmetrically-shaped fiducial is used. The type and shape of this fiducial also contribute to the sensitivity of rotational detection in respiratory tracking.

It has been a constant concern for clinicians on the realistic dose differences computed with an early-available finite size pencil beam algorithm (FSPB) for the treatment plans using a multileaf collimators equipped robotic radiosurgery system (RR-MLC) from the doses computed by an industry well-accepted algorithm, such as Monte Carlo dose algorithm (MC). This study was designed to quantify these dose disparities in the RR-MLC treatment plans for selected anatomic sites in using both FSPB and MC. A total of forty RR-MLC stereotactic ablative radiation therapy (SART) plans computed with FSPB were retrospectively reviewed and compared with MC computed results, including plans for detached lung cancer (or tumors fully surrounded by lung tissues,n=10), non-detached lung cancer (or tumor touched the chest wall or mediastinum, n=10), intracranial(n=10), and pancreas lesions(n=5). MC was commissioned with an uncertainty of 0.2%. All the selected plans were recomputed in the Precision™ planning system for both algorithms with the identical set of contours, optimizations, and MU’s. The dosimetry for planning tumor volume (PTV) and major organ at risks (OAR) was compared with each paired plan. A “normalized deviation” (N_dev=(MC-FSPB)/FSPB) and paired two sample t-tests were used for quantitative analysis. AS shown in Table 1, FSPB plans of RR-MLC overestimates D95 of PTV by averaging 18.9% when compared with the MC computed plans in detached lung cases, and 17.0% in non-detached lung cases. These dose differences appear much less in intracranial and pancreas cases, the differences of D95 of PTV are 1.3% and 2.0% respectively. The lung SART plans encompass the situation with the largest tissue density heterogeneity among all the groups, especially those for detached lung tumors where the disadvantage of FSPB shows largest in dose computations. There is less significant difference (1.3-4.9%) between FSPB and MC calculated maximum dose to OAR’s in each case. The results from this investigation suggest a significant dose difference between lung SART plans computed with FSPB and MC, in which FSPB overestimates D95 of the lung PTV by about 17% to 18.9% and slightly underestimates the hot spots in the surrounding OAR by about 5% or less. The dose differences between plans using the two algorithms are about 2% of less in SART plans for intracranial and pancreatic lesions. These results shall provide a useful guide in evaluating RR-MLC plans when MC is not used.Abstract TU_31_3199; Table 1Dosimetry Comparisons of RR-MLC Plans Computed with FSPB and MC for Selected SitesPTV DosesNon-Detached lungDetached lungPancreasIntracranialN_devp-valueN_devp-valueN_devP-valueN_devp-valueD95-17.0%<0.001-18.9%0.013-1.3%0.128-2.0%0.013Dmean-13.8%<0.001-14.7%0.0626-1.2%0.062-1.1%0.0626Dmax-5.2%<0.001-4.5%<0.0015.1%0.0024.3%<0.001 Open table in a new tab

BACKGROUND:This collaborative practice parameter technical standard has been created between the American College of Radiology and American Brachytherapy Society to guide the usage of electronically generated low energy radiation sources (ELSs). It refers to the use of electronic X-ray sources with peak voltages up to 120 kVp to deliver therapeutic radiation therapy.MAIN FINDINGS:The parameter provides a guideline for utilizing ELS, including patient selection and consent, treatment planning, and delivery processes. The parameter reviews the published clinical data with regard to ELS results in skin, breast, and other cancers.CONCLUSIONS:This technical standard recommends appropriate qualifications of the involved personnel. The parameter reviews the technical issues relating to equipment specifications as well as patient and personnel safety. Regarding suggestions for educational programs with regard to this parameter,it is suggested that the training level for clinicians be equivalent to that for other radiation therapies. It also suggests that ELS must be done using the same standards of quality and safety as those in place for other forms of radiation therapy.

Non-small lung cancer (NSCLC) is the most common type of lung cancer in the US with overall 5 year survival of only 21%. Stereotactic body radiation surgery (SBRT) is a standard of care for the medically inoperable early-stage NSCLC patients. Up until recently, the significance of tumor histology for loco-regional control (LRC) remained unclear possibly due to lack of stratification by tumor histology. We recently showed that NSCLC tumors with squamous histology treated by SBRT (50 Gyx5) exhibit significantly higher locoregional recurrence compared to adenocarcinomas. Since biologically effective dose (BED)>100 Gy had been previously associated with improved LRC in early stage NSCLC, we investigated the effects of dose escalation on LRC of distinct histological types of NSCLC by retrospectively analyzing cases of NSCLC treated with SBRT. 223 early-stage NSCLC cases treated at a single institution from 12/2008 to 03/2016 were retrospectively analyzed. The median age of our patients was 82 years (49-95) and the mean follow-up was 2.4 years (0.5-5.8). A 4D CT simulation was done prior to the treatment. The treatment volume included respiratory motion (ITV) with a 5 mm margin (PTV). 117 patients were treated with 50 Gy over 5 consecutive days (BED10 of 100 Gy). 106 patients were treated with 55-60 Gy over 5 consecutive days (BED10 of 115.5-132 Gy). 45% of local recurrences were confirmed by biopsy. Radiographic recurrences were defined using CT-based high risk Huang criteria. In accordance with literature data, the local recurrence rate observed in our retrospective study was 10.1%. Overall, squamous histology of early stage NSCLC had a much higher rate of local failure (28.1% vs 8.1%, P=0.004), and also higher rate of regional failure (25% vs 7.5%, P=0.007) as compared to adenocarcinoma, consistent with our previous report. The mean follow-up was 2.6 years for adenocarcinoma (range 0.5-5.8 years) and 2 years for squamous histology cases (range 0.5-5.6 years). Strikingly, squamous NSCLC cases treated with BED>100 Gy (BED10 of 115.5-132 Gy) showed a significant reduction of local failure (12.5% vs 43.8%, P=0.05) as compared to the squamous cases treated with BED10 of 100 Gy. In addition, there was a trend towards a reduction of regional recurrence rates (18.8% vs 31.3%, P>0.05). There was no difference in the distant metastatic disease between squamous carcinoma cases treated with either BED10 of 100 Gy or BED>100 Gy (distant recurrence rate of 25% for both). No statistically significant difference in LRC was observed for adenocarcinoma cases treated with either BED10 of 100 Gy or BED>100 Gy. Squamous histology cases treated with BED>100 Gy showed a significant improvement in local control. We propose that a BED>100 Gy should be used routinely for treatment of squamous histology cases. A dose escalation trial is needed to identify the optimal dose and fractionation scheme for early stage squamous NSCLC.

PURPOSE: To report updated feasibility and reproducibility results for high-dose-rate noninvasive breast brachytherapy (NIBB) for tumor bed boost with whole breast radiation therapy (WBRT) in the setting of expanded patient and treatment facility number.METHODS AND MATERIALS: Fifteen independent community-based and academic centers reported 518 early-stage breast cancer patients from July 2007 to February 2015 on a privacy-encrypted online data registry. All patients' treatment included lumpectomy followed by combination of WBRT and NIBB. NIBB was completed with commercially available (AccuBoost, Billerica, MA) mammography-based system using high-dose-rate Ir-192 emissions along orthogonal axes. Harvard scale was used to grade cosmesis.RESULTS: Total patient cohort had median followup of 12 months (1-75 months) with subset of 268 having available cosmesis. Greater than 2- and 3-year followup was 29% and 14%, respectively. Entire cohort had 97.4% excellent/good (E/G) breast cosmesis and freedom from recurrence of 97.6% at the final followup. WBRT timing with respect to NIBB delivery demonstrated no statistically significant difference in E/G cosmesis. Achieved E/G cosmesis rate was also not statistically significant (x(2) p value = 0.86) between academic and community institutions with 97.8% vs. 96.6%.CONCLUSIONS: NIBB represents an alternative method for delivery of breast tumor cavity boost that has shown feasibility in a diverse group of both academic and community-based practices with reproducible early cosmesis and tumor control results. Recommendations are updated noting ideal timing of boost delivery likely to be before or early during WBRT given equal cosmesis and less documented treatment discomfort. (C) 2016 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Non-small cell lung cancer (NSCLC) represents 85% of all lung cancer cases, with early-stage accounting for 18% of NSCLC cases. While surgical resection remains the primary treatment for early stage NSCLC for lesions 5 cm or less, stereotactic body radiation therapy (SBRT) has become an excellent alternative. Recent studies had shown that SBRT achieved excellent local control rates of 80-90%, and impressive overall survival rates of up to 95% in early-stage NSCLC patients with a 3-5 year follow-up. Adenocarcinomas, followed by squamous cell carcinomas (SCC) are the most common histological subtypes of NSCLC. The significance of tumor cell histology for locoregional control is largely unknown. From the limited publications, factors associated with locoregional failure include presence of serum carcinoembryonic antigen, lymphovascular invasion, and tumor size >2.7 cm. This study was designed to investigate the relevance of lung tumor cell histology/subtypes for local tumor control by retrospectively analyzing cases of NSCLC treated with SBRT. One hundred seventeen early stage NSCLC (135 nodules) cases treated at a single institution from 12/2008 to 11/2012 were analyzed. The median age of our patients was 81(49-95) years and median follow-up was 3.1 years (0.5-5.8). A 4D CT simulation was done prior to the treatment. The treatment volume included respiratory motion (ITV) with a 5mm margin (PTV). The treatment dose was 50 Gy over 5 consecutive days. The tumor subtypes in this group included adenocarcinomas (81.5%), SCC (12.5%), and unknown (6%). The overall rate of local recurrence was 10.4%, which is consistent with published literature. Cases with squamous cell histology showed a significantly higher rate of local recurrence as compared to adenocarcinoma (35.3% vs 7.3% respectively, P<0.01). In addition, the regional recurrence rate was also higher in SCC cases (23.5% vs 3.6%, P<0.05). There was no difference in the rates of distal recurrence between these histological tumor subtypes (17.3% for adenocarcinoma vs 17.6% for SCC). In addition, no differences were identified in patient age, mean follow-up time, sex, tumor size or stage, maximum SUV, or dose delivered. However, there was a trend (P >0.05) towards a larger lesion size (mean of 23.7 mm for SCC vs 21.0 mm for adenocarcinomas) and more advanced tumor stage (T1b of 41.2% for SCC vs 30.9% for adenocarcinoma) in SCC subgroup. With a conservative dose scheme of SBRT for NSCLC, squamous cell carcinomas showed higher local and regional recurrence rates as compared to adenocarcinomas. The results of this study should be taken with caution given the relatively small numbers of patients, and the trends toward larger lesion sizes and more advanced tumor stages in the SCC subgroup. Nevertheless, the findings in this study may suggest a more aggressive approach for squamous cell histology. We initiated a central boost of an additional 5Gy at our institution since 2013. We plan to analyze these data for future reporting.

PURPOSE: The aim of this study was to define current patterns of care among radiation oncologists who use skin surface brachytherapy for the treatment of cutaneous squamous cell carcinoma (cSCC) and basal cell carcinoma (BCC) in academic and community settings.METHODS AND MATERIALS: A 30-question electronic survey was administered to clinician members of the American Brachytherapy Society. The respondents were asked to provide details regarding their clinical practice and their approach to skin surface brachytherapy.RESULTS: A total of 16 surveys were returned. Among the respondents, aggregate experience varied from 8 to 1800 cases. Most preferred brachytherapy over external beam radiation because of shorter treatment course, conformality of treatment for irregular or curved targets, and shallow dose deposition. Of the total, 60% of respondents routinely estimated lesion depth via ultrasound before initiating treatment. Treatment margin on gross disease varied widely (range, 3-15 mm; median, 5 mm). Hypofractionation was the preferred dose schedule. Prescribed doses ranged from 30 Gy in five fractions to 64 Gy in 32 fractions (EQD2, 40 Gy-65 Gy). There was a tendency to increase the number of fractions for larger targets, although some used the same fractionation regardless of anatomic location or lesion size. There was no consensus on dosimetric constraints, and some respondents reported cases of severe toxicity, particularly when treating the pretibial skin.CONCLUSIONS: This pattern of care study suggests that skin brachytherapy can be a convenient and safe tool for treatment of BCC and cSCC. Prospective trials and the development of expert consensus guidelines would be beneficial for optimizing skin surface brachytherapy and reducing practice variation. (C) 2016 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

PurposeNonmelanoma skin cancers (NMSCs) are the most common type of human malignancy. Although surgical techniques are the standard treatment, radiation therapy using photons, electrons, and brachytherapy (BT) (radionuclide-based and electronic) has been an important mode of treatment in specific clinical situations. The purpose of this work is to provide a clinical and dosimetric summary of the use of BT for the treatment of NMSC and to describe the different BT approaches used in treating cutaneous malignancies.Methods and MaterialsA group of experts from the fields of radiation oncology, medical physics, and dermatology, who specialize in managing cutaneous malignancies reviewed the literature and compiled their clinical experience regarding the clinical and dosimetric aspects of skin BT.ResultsA dosimetric and clinical review of both high dose rate (192Ir) and electronic BT treatment including surface, interstitial, and custom mold applicators is given. Patient evaluation tools such as staging, imaging, and patient selection criteria are discussed. Guidelines for clinical and dosimetric planning, appropriate margin delineation, and applicator selection are suggested. Dose prescription and dose fractionation schedules, as well as prescription depth are discussed. Commissioning and quality assurance requirements are also outlined.ConclusionsGiven the limited published data for skin BT, this article is a summary of the limited literature and best practices currently in use for the treatment of NMSC.

Nonmelanoma skin cancer (NMSC) is an increasing health care issue in the United States, significantly affecting quality of life and impacting health care costs. Radiotherapy has a long history in the treatment of NMSC. Shortly after the discovery of X-rays and (226)Radium, physicians cured patients with NMSC using these new treatments. Both X-ray therapy and brachytherapy have evolved over the years, ultimately delivering higher cure rates and lower toxicity. Electronic brachytherapy for NMSC is based on the technical and clinical data obtained from radionuclide skin surface brachytherapy and the small skin surface applicators developed over the past 25 years. The purpose of this review is to introduce electronic brachytherapy in the context of the history, data, and utilization of traditional radiotherapy and brachytherapy.

PURPOSE:Radiotherapy (RT) has played a significant role in treating non melanoma skin cancer (NMSC). High-dose-rate brachytherapy (HDR-BT) approaches have a paramount relevance due to their adaptability, patient protection, and variable dose fractionation schedules. Several innovative applicators have been introduced to the brachytherapy community. The Valencia applicator is a new superficial device that improves the dose distribution compared with the Leipzig applicator. The purpose of this work is to assess the tumor control, cosmesis, and toxicity in patients with NMSC treated with the Valencia applicator and a new regimen of hypofractionation.MATERIAL AND METHODS:From January 2008 to March 2010, 32 patients with 45 NMSC lesions were treated with the Valencia applicator in the Hospital La Fe. The gross tumor volume was visually assessed, but the tumor depth was evaluated using ultrasound imaging. All lesions for the selected cases were limited to 4 mm depth. The prescription dose was 42 Gy in 6 or 7 fractions (biologically effective dose [BED] ≈ 70 Gy), delivered twice a week.RESULTS:Ninety-eight percent of the lesions were locally controlled at 47 months from treatment. Ninety-three percent of patients were out at least 36 months from treatment. The treatment was well tolerated in all cases. The highest skin toxicity was grade 1 RTOG/EORTC, having resolved with topical treatment at 4 weeks in all but one case which required 2 months. There were no grade 2 or higher late adverse events.CONCLUSIONS:In patients with superficial basal cell carcinoma lesions less than 25 mm in maximum diameter, HDRBT treatment with the Valencia applicator using a hypofractionated regimen provides excellent results, for both cosmetic and local control at a minimum of 3 years follow-up. Moreover, the shorter hypofractionated regimen facilitates compliance, which is very relevant for the elderly patients in our series. Valencia applicators offer a simple, safe, quick, and attractive nonsurgical treatment option.