Post-excision RT shows significant reduction in keloid recurrence compared to excision alone. While the recurrence control rates are not statistically different between EBRT and brachytherapy, keloids treated with EBRT recurred significantly later than those treated by HDR brachytherapy by a mean of 2.5 years. Further workup with a randomized control study will help to refine optimal adjuvant RT treatment. LEVEL OF EVIDENCE 3.

PurposeTo evaluate use of breath-hold CTs and implanted fiducials for definition of the internal target volume (ITV) margin for upper abdominal stereotactic body radiation therapy (SBRT). To study the statistics of inter- and intra-fractional motion information.Methods and materials11 patients treated with SBRT for locally advanced pancreatic cancer (LAPC) or liver cancer were included in the study. Patients underwent fiducial implantation, free-breathing CT and breath-hold CTs at end inhalation/exhalation. All patients were planned and treated with SBRT using volumetric modulated arc therapy (VMAT). Two margin strategies were studied: Strategy I uses PTV = ITV + 3 mm; Strategy II uses PTV = GTV + 1.5 cm. Both CBCT and kV orthogonal images were taken and analyzed for setup before patient treatments. Tumor motion statistics based on skeletal registration and on fiducial registration were analyzed by fitting to Gaussian functions.ResultsAll 11 patients met SBRT planning dose constraints using strategy I. Average ITV margins for the 11 patients were 2 mm RL, 6 mm AP, and 6 mm SI. Skeletal registration resulted in high probability (RL = 69%, AP = 4.6%, SI = 39%) that part of the tumor will be outside the ITV. With the 3 mm ITV expansion (Strategy 1), the probability reduced to RL 32%, AP 0.3%, SI 20% for skeletal registration; and RL 1.2%, AP 0%, SI 7% for fiducial registration. All 7 pancreatic patients and 2 liver patients failed to meet SBRT dose constraints using strategy II. The liver dose was increased by 36% for the other 2 liver patients that met the SBRT dose constraints with strategy II.ConclusionsImage guidance matching to skeletal anatomy is inadequate for SBRT positioning in the upper abdomen and usage of fiducials is highly recommended. Even with fiducial implantation and definition of an ITV, a minimal 3 mm planning margin around the ITV is needed to accommodate intra-fractional uncertainties.

Purpose Dynamic magnetic resonance imaging (MRI) has been used to characterize internal organ motion but real time acquisition is typically limited to 2 dimensions. Methods have been developed to reconstruct four dimensional MRI (4D-MRI) based on time-stamped 2D images or 2D K-space data. These methods suffer from anisotropic resolution and rebinning artifacts. We applied a novel self-gating K-space sorted 4D-MRI (SG-KS-4D-MRI) method to overcome these limitations and to monitor pancreatic tumor motion. Methods and Material Ten patients were imaged using 4D-CT, cine 2D-MRI and the SG-KS-4D-MRI, which is a spoiled gradient recalled echo (GRE) sequence with 3D radial-sampling K-space projections and 1D projection-based self-gating. Tumor volumes were defined on all phases in both 4D-MRI and 4D-CT and then compared. Results An isotropic resolution of 1.56 mm was achieved in the SG-KS-4D-MRI images, which showed superior soft tissue contrast to 4D-CT and appeared to be free of visible rebinning artifacts. The tumor motion trajectory cross-correlations between SG-KS-4D-MRI and cine 2D-MRI in SI, AP and ML directions were 0.93±0.03, 0.83±0.10 and 0.74±0.18, respectively. The tumor motion trajectories cross-correlations between SG-KS-4D-MRI and 4D-CT in SI, AP and ML directions were 0.91±0.06, 0.72±0.16 and 0.44±0.24, respectively. The average standard deviation of GTV volume (GTV_σ) calculated from the ten breathing phases were 0.81 cc and 1.02 cc for SG-KS-4D-MRI and 4D-CT (p=0.012). Conclusions A novel SG-KS-4D-MRI acquisition method capable of reconstructing rebinning artifact free high resolution 4D-MRI images was used to quantify pancreas tumor motion. The resultant pancreatic tumor motion trajectories agreed well with 2D-cine-MRI and 4D-CT. The pancreatic tumor volumes shown in the different phases for the SG-KS-4D-MRI were statistically significantly more consistent than those in the 4D-CT.

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer deaths in both men and women in the United States, carrying a 5-year survival rate of approximately 5%, which is the poorest prognosis of any solid tumor type. Given the dismal prognosis associated with PDAC, a more thorough understanding of risk factors and genetic predisposition has important implications not only for cancer prevention, but also for screening techniques and the development of personalized therapies. While screening of the general population is not recommended or practicable with current diagnostic methods, studies are ongoing to evaluate its usefulness in people with at least 5-to 10-fold increased risk of PDAC. In order to help identify high-risk populations who would be most likely to benefit from early detection screening tests for pancreatic cancer, discovery of additional pancreatic cancer susceptibility genes is crucial. Thus, specific gene-based, gene-product, and marker-based testing for the early detection of pancreatic cancer are currently being developed, with the potential for these to be useful as potential therapeutic targets as well. The goal of this review is to provide an overview of the genetic basis for PDAC with a focus on germline and familial determinants. A discussion of potential therapeutic targets and future directions in screening and treatment is also provided.

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The purpose was to report clinical experience of a video‐guided spirometry system in applying deep inhalation breath‐hold (DIBH) radiotherapy for left‐sided breast cancer, and to study the systematic and random uncertainties, intra‐ and interfraction motion and impact on cardiac dose associated with DIBH. The data from 28 left‐sided breast cancer patients treated with spirometer‐guided DIBH radiation were studied. Dosimetric comparisons between free‐breathing (FB) and DIBH plans were performed. The distance between the heart and chest wall measured on the digitally reconstructed radiographs (DRR) and MV portal images, dDRR(DIBH) and dport(DIBH), respectively, was compared as a measure of DIBH setup uncertainty. The difference (Δd) between dDRR(DIBH) and dport(DIBH) was defined as the systematic uncertainty. The standard deviation of Δd for each patient was defined as the random uncertainty. MV cine images during radiation were acquired. Affine registrations of the cine images acquired during one fraction and multiple fractions were performed to study the intra‐ and interfraction motion of the chest wall. The median chest wall motion was used as the metric for intra‐ and interfraction analysis. Breast motions in superior–inferior (SI) direction and “AP” (defined on the DRR or MV portal image as the direction perpendicular to the SI direction) are reported. Systematic and random uncertainties of 3.8 mm and 2 mm, respectively, were found for this spirometer‐guided DIBH treatment. MV cine analysis showed that intrafraction chest wall motions during DIBH were 0.3 mm in “AP” and 0.6 mm in SI. The interfraction chest wall motions were 3.6 mm in “AP” and 3.4 mm in SI. Utilization of DIBH with this spirometry system led to a statistically significant reduction of cardiac dose relative to FB treatment. The DIBH using video‐guided spirometry provided reproducible cardiac sparing with minimal intra‐ and interfraction chest wall motion, and thus is a valuable adjunct to modern breast treatment techniques.PACS number: 87.55.kh, 87.55.ne, 87.55.tg

Purpose Bone metastases are reported in 10% to 12% of patients with neuroendocrine neoplasms (NENs) and can lead to pain and skeletal-related events (SREs), resulting in diminished quality of life and functional status. In other solid tumors with bone metastases, radiation therapy (RT) is an established treatment approach for SREs, yet few data are available in NENs historically considered to be radioresistant. We hypothesize that RT is effective for pain and other SREs in NENs and aimed to delineate any differences in pain palliation and time until progression of pain between different fractionation and dosing schedules of RT. Methods and Materials We retrospectively reviewed 686 records of patients with NENs treated at the institution between 2011 and 2018 and identified 28 (4.1%) patients treated with RT for 61 cases of SREs. The primary endpoint was change in patient reported pain scores after RT. Results All 28 patients experienced bone pain. Nineteen sites were treated with a single fraction (doses of 800-1800 cGy) and 42 sites with fractionated regimens (doses of 900-3750 cGy over 3-15 fractions). In 55 of 61 cases (90%), patients experienced improvement in pain after RT. The median time to recurrence or progression of pain was 3.5 months. Significant differences were found between primary site and change in performance status ( P = .024), sex, and reported magnitude of pain score decrease after RT ( P = .025). There were no differences in the time to the progression of pain, change in performance status, and degree of improvement in pain based on age, chemotherapy received during RT, or radiation site. Outcomes were similar for patients who received single-fraction versus fractionated regimens ( P = .545) and between those receiving palliative versus ablative RT regimens ( P = .812). Conclusions Although the majority of cases in this NEN cohort benefited from RT, additional studies on the use of RT in the treatment of painful bone metastases are warranted.

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