Automated Test for Monthly Quality Assurance of Optical Surface Imaging Dynamic Localization Accuracy

The American Association of Physicists in Medicine (AAPM) recently published the report of Task Group (TG) 302, which provides recommendations on acceptance, commissioning, and ongoing routine quality assurance (QA) for surface-guided radiation therapy (SGRT) systems. One of the recommended monthly QA tests is a dynamic localization accuracy test. This work aimed to develop an automated procedure for monthly SGRT dynamic localization QA. An anthropomorphic head phantom was rigidly attached to the 6-dof couch of a TrueBeam linac. TrueBeam Developer Mode was used to take an MV image of the phantom at the starting position, then automatically drive the couch through a series of translations and rotations, taking an MV image after each translation. The Identify SGRT system monitored the motion of the phantom surface from the starting position. Translations assessed on MV images were compared to translations reported in trajectory log files and Identify log files. Rotations were compared between trajectory log files and Identify log files. Three experiments were conducted. None of the translations or rotations from any experiment exceeded the tolerance values for stereotactic ablative body radiation therapy (SABR) recommended by AAPM TG-142. Maximum deviations from the expected translation values from MV imaging, trajectory log files, and Identify log files were -0.94mm, -0.11mm, and -0.78mm, respectively. Maximum deviations from the expected rotation values from trajectory log files and Identify log files were 0.01 and -0.2 degrees, respectively. The proposed method is a simple automated way to complete monthly dynamic localization QA of SGRT systems.

A Review of Hodgkin Lymphoma in the Era of Checkpoint Inhibitors

Hodgkin lymphoma (HL) is a hematopoietic malignancy of B-cells that has a bimodal distribution with respect to age and incidence. With the introduction of doxorubicin (Adriamycin), bleomycin, vinblastine, and dacarbazine (ABVD) and radiation combined, the prognosis of HL has significantly improved, with five-year survival rates approaching 95%. While HL has become highly curable, the side effect profiles of ABVD are dire and warrant continuous review. Because HL is often diagnosed in populations in their 20s-30s, patients are forced to undergo fertility preservation procedures as well as deal with other long-term side effects of chemotherapy (including doxorubicin dose-dependent cardiotoxicity and bleomycin-induced lung toxicity). The opportunity cost of the treatment in the short term and vulnerability to treatment-induced malignancies decades later dramatically affect the quality of life of HL patients. New therapies have developed over the past several decades with respect to immunotherapies, particularly programmed death protein 1 inhibitors (e.g., nivolumab and pembrolizumab). Studies have shown checkpoint inhibitors to be effective in treating HL with an objective response rate of 69% for relapsed/refractory classical HL for nivolumab use. Checkpoint inhibitors will continue to help maintain the high five-year survival rate for HL and hopefully have a more favorable side effect profile in the short term, as well as later in the patient's life. This article seeks to summarize treatment options for HL while comparing outcomes and side effect profiles with the addition of checkpoint inhibitors.

A Case Report of Kearns-Sayre Syndrome: Not an Absolute Contraindication for Radiotherapy

Kearns-Sayre syndrome (KSS) is a rare mitochondrial disorder, and the effects of radiotherapy on such a population group are unknown. A 60-year-old male with a history of KSS was diagnosed with locally advanced basal cell carcinoma along the left inner canthus. He was treated at our institution with curative intent radiotherapy alone and tolerated it well with no major acute or late toxicities. There was a complete clinical and radiological response of the tumor, with no evidence of recurrence 2.5 years after treatment. Further research is needed to explore the effects of ionizing radiation on patients with mitochondrial DNA defects.

The Association of Radiation Dose With Overall Survival for Patients Treated With Prostate Stereotactic Body Radiation Therapy

Introduction Stereotactic body radiation therapy (SBRT) for prostate adenocarcinoma (PCa) has demonstrated excellent biochemical recurrence-free survival, with studies showing improved BRFS with higher-dose SBRT. However, current studies have been underpowered to evaluate the relationship of SBRT dose to overall survival (OS). In this retrospective study using the National Cancer Database (NCDB), we hypothesize that, given the low alpha/beta ratio of PCa, a relatively small increase in the dose-per-fraction would be associated with improved survival outcomes for intermediate-risk PCa (IR-PCa) comparing 36.25 Gy/5 fx [biologically equivalent dose (BEDα/β = 1.5 = 211.46 Gy vs. 35 Gy (BED1.5 = 198.33 Gy)]. Materials and methods We queried records from the NCDB from 2005 to 2015 for men receiving prostate SBRT for IR-PCa (n=2673). 82% were treated using either 35 Gy/5 fx or 36.25 Gy/5 fx. We compared OS in men receiving 35 Gy versus 36.25 Gy. Inverse probability of treatment weighting (IPTW) was used to adjust for covariable imbalances. Unweighted- and weighted-multivariable analysis (MVA) using Cox regression was used to compare OS hazard ratios, accounting for age, race, Charlson-Deyo comorbidity score, treatment facility type, prostate-specific antigen (PSA), clinical T-stage, Gleason Score, and use of androgen deprivation therapy (ADT). Kaplan-Meier analysis was performed. Results Seven hundred and eighty men (35%) were treated with 35 Gy/5 fx and 1434 men (65%) were treated with 36.25 Gy/5 fx (n=2214). Compared to 35 Gy, treatment with 36.25 Gy was associated with significantly improved OS (hazard ratio [HR]: 0.61 [95% CI: 0.43-0.89], P=0.009) on MVA. On Kaplan-Meier analysis, 36.25 Gy was associated with improved survival (p=0.034), with a five-year OS of 92% and 88%, respectively. Conclusions In a multi-institutional retrospective database of 2,214 IR patients treated with prostate SBRT, a prescription dose of 36.25 Gy/5 fx was associated with improved OS vs. 35 Gy/5 fx. Results are hypothesis-generating but do lend support to the current National Comprehensive Cancer Network (NCCN) guidelines that the minimum recommended dose for prostate SBRT is 36.25 Gy/5 fx.

Rectal Squamous Cell Cancer

Squamous cell carcinoma occurring in the rectum is one of the rare malignancies that has been discovered. Most squamous cell carcinomas that surface in the gastrointestinal tract tend to occur in either the esophagus or the anal canal. However, the rare incidence of rectal squamous cell carcinomas has raised quite a few questions on the hypothetical etiologies, prognosis, and optimal treatment sequence of such a disease course in modern medicine. In this report, we present the case of a 63-year-old gentleman who came to the clinic with change in bowel habits such as constipation and bright red blood in his stool. Colonoscopy revealed a 4.1 cm polyp in the distal rectum, which upon biopsy was confirmed to be a well-differentiated keratinizing squamous cell carcinoma. This case allows us to engage in discussions over potential etiologies and current treatment management for such a rare malignancy.