Patrick Tripp

Elective Lymph Node Irradiation With Intensity-Modulated Radiotherapy: Is Conventional Dose Fractionation Necessary?

PURPOSE Intensity-modulated radiation therapy (IMRT) is the standard of care for head-and-neck cancer (HNC). We treated patients with HNC by delivering either a moderate hypofractionation (MHF) schedule (66 Gy at 2.2 Gy per fraction to the gross tumor [primary and nodal]) with standard dose fractionation (54-60 Gy at 1.8-2.0 Gy per fraction) to the elective neck lymphatics or a conventional dose and fractionation (CDF) schedule (70 Gy at 2.0 Gy per fraction) to the gross tumor (primary and nodal) with reduced dose to the elective neck lymphatics. We analyzed these two cohorts for treatment outcomes. METHODS AND MATERIALS Between November 2001 and February 2009, 89 patients with primary carcinomas of the oral cavity, larynx, oropharynx, hypopharynx, and nasopharynx received definitive IMRT with or without concurrent chemotherapy. Twenty patients were treated using the MHF schedule, while 69 patients were treated with the CDF schedule. Patient characteristics and dosimetry plans were reviewed. Patterns of failure including local recurrence (LR), regional recurrence (RR), distant metastasis (DM), disease-free survival (DFS), overall survival (OS), and toxicities, including rate of feeding tube placement and percentage of weight loss, were reviewed and analyzed. RESULTS Median follow-up was 31.2 months. Thirty-five percent of patients in the MHF cohort and 77% of patients in the CDF cohort received chemotherapy. No RR was observed in either cohort. OS, DFS, LR, and DM rates for the entire group at 2 years were 89.3%, 81.4%, 7.1%, and 9.4%, respectively. Subgroup analysis showed no significant differences in OS (p = 0.595), DFS (p = 0.863), LR (p = 0.833), or DM (p = 0.917) between these two cohorts. Similarly, no significant differences were observed in rates of feeding tube placement and percentages of weight loss. CONCLUSIONS Similar treatment outcomes were observed for MHF and CDF cohorts. A dose of 50 Gy at 1.43 Gy per fraction may be sufficient to electively treat low-risk neck lymphatics.

Initiative to reduce bone scans for low-risk prostate cancer patients: A quasi-experimental before-and-after study in a Veterans Affairs hospital

Purpose Bone scans (BS) are a low-value test for asymptomatic men with low-risk prostate cancer. We performed a quality improvement intervention aimed at reducing BS for these patients. Methods and materials The intervention was a presentation that leveraged the behavioral science concepts of social comparison and normative appeals. Participants were multidisciplinary stakeholders from the Radiation Oncology and Urology services at a Veterans Affairs hospital. We determined the baseline rate of BS by retrospectively analyzing cases of asymptomatic men with newly diagnosed low-risk prostate cancer. For social comparison, we presented contemporary peer BS rates in the United States—including Veterans Affairs hospitals. For normative appeals, we reviewed guidelines from various professional groups. To analyze the effect of this intervention, we performed a quasi-experimental, uncontrolled, before-and-after study. Results During the 1-year period before the intervention, 32 of 37 patients with low-risk prostate cancer (86.5%) received a BS. The contemporary peer rate was approximately 30%. All reviewed guidelines recommended against BS. During the 1-year period after the intervention, the rate of BS was reduced to 65.5% (19 of 29 patients; P = .043 by one-sided Fishers exact test). Conclusions We observed a modest reduction in guideline-discordant BS after the quality improvement intervention. BS rates might be influenced by initiatives that combine social comparisons with appeals to professional norms.

Angiosarcoma of the Bladder Following Prostate Radiotherapy

To the Editor:Prostate cancer, the most common malignancy in men,is often managed with radiotherapy. Treatment is generallywell-tolerated; patients have a minimum to moderate inci-dence of urinary irritation, bowel frequency, and erectiledysfunction. A much rarer but real concern is radiation-induced secondary malignancies. We present the case ofan unusual bladder cancer arising after prostate radio-therapy. Primary care physicians, urologists, and oncolo-gists who follow prostate cancer survivors should be awareof the risk of secondary tumors.

Diagnosis to Treatment Interval and Outcome in Patients with Locally- Advanced Squamous Cell Carcinoma of the Head and Neck in a Veterans Affairs Medical Center

Background: Treatment of locally-advanced squamous cell carcinoma of the head and neck (SCCHN) requires multi-disciplinary care often resulting in a prolonged diagnosis to treatment interval (DTI). This study aims to identify factors that influence DTI and to assess the impact of DTI on treatment outcomes. Methods: The medical records of 135 patients with SCCHN who were treated with definitive chemoradiotherapy between 2000 and 2009 at the Clement J Zablocki VA Medical Center were reviewed and analyzed. Results: Median DTI was 44 days. A Cox-Model identified that transfer patients had prolonged DTI. Longer DTI had a significant negative impact on overall survival (RR 1.009, p = 0.0386) but did not impact distant (RR 0.99, p = 0.89) or local control (0.99, p = 0.23). Conclusion: Increased DTI in patients with SCCHN results in a statistically significant negative survival impact. Efforts need to be directed to improving DTI and on expediting and streamlining the care of transfer patients.

TU‐EE‐A1‐01: Accuracy of Clinical Dose Delivery in IOHDR Brachytherapy

Purpose: To investigate the accuracy of clinical dose delivery in intra‐operative high dose rate (IOHDR) brachytherapy.Method and Materials: The IOHDR brachytherapytreatments of 10 patients recently treated at our facility were reconstructed. Treatment geometries reflecting each clinical scenario were simulated by a phantom assembly with no added buildup on top of the applicator. EDR2 radiographic film placed at the prescription depth recorded dose distributions for each clinical case. The treatment planning geometry (full scatter surrounding the applicator) was subsequently simulated for each case by adding bolus on top of the applicator and radiographic film was again exposed at the treatment depth. After careful determination of the films H&D curve, absolute dose distributions in the plane of the prescription depth were evaluated for both scatter environments in each clinical case. Results: For the geometries simulating the treatment planning conditions of full scatter, the average dose measured at the treatment depths was within 2% of the prescription and dose distributions were in excellent agreement with the respective treatment plan. However, for the geometry simulating treatment conditions (no added scattering material above the applicator), the dose at the prescription depth was on average 11% lower (range 8–14%) than prescribed. An analysis of the delivered dose distributions and treatment plans shows a resulting average decrease of 2 mm (range 1.2–2.4 mm) in prescription depth. Conclusion:Dosimetry calculations for IOHDR brachytherapy are typically done with treatment planning systems with dose calculation algorithms that assume an infinite scatter environment around the applicator and target volume. We have shown that this assumption leads to dose delivery errors which result in significant foreshortening of the prescription depth. It may be clinically relevant to correct for these errors by augmenting the scatter environment or, preferably, by appropriately modifying the prescription dose entered into the treatment planning system.