Rajni Sethi

Evaluation of PC-ISO for Customized, 3D Printed, Gynecologic 192-Ir HDR Brachytherapy Applicators

The purpose of this study was to evaluate the radiation attenuation properties of PC‐ISO, a commercially available, biocompatible, sterilizable 3D printing material, and its suitability for customized, single‐use gynecologic (GYN) brachytherapy applicators that have the potential for accurate guiding of seeds through linear and curved internal channels. A custom radiochromic film dosimetry apparatus was 3D‐printed in PC‐ISO with a single catheter channel and a slit to hold a film segment. The apparatus was designed specifically to test geometry pertinent for use of this material in a clinical setting. A brachytherapy dose plan was computed to deliver a cylindrical dose distribution to the film. The dose plan used an 192Ir source and was normalized to 1500 cGy at 1 cm from the channel. The material was evaluated by comparing the film exposure to an identical test done in water. The Hounsfield unit (HU) distributions were computed from a CT scan of the apparatus and compared to the HU distribution of water and the HU distribution of a commercial GYN cylinder applicator. The dose depth curve of PC‐ISO as measured by the radiochromic film was within 1% of water between 1 cm and 6 cm from the channel. The mean HU was ‐10 for PC‐ISO and ‐1 for water. As expected, the honeycombed structure of the PC‐ISO 3D printing process created a moderate spread of HU values, but the mean was comparable to water. PC‐ISO is sufficiently water‐equivalent to be compatible with our HDR brachytherapy planning system and clinical workflow and, therefore, it is suitable for creating custom GYN brachytherapy applicators. Our current clinical practice includes the use of custom GYN applicators made of commercially available PC‐ISO when doing so can improve the patients treatment. PACS number: none

Clinical applications of custom-made vaginal cylinders constructed using three-dimensional printing technology

Purpose Three-dimensional (3D) printing technology allows physicians to rapidly create customized devices for patients. We report our initial clinical experience using this technology to create custom applicators for vaginal brachytherapy. Material and methods Three brachytherapy patients with unique clinical needs were identified as likely to benefit from a customized vaginal applicator. Patient 1 underwent intracavitary vaginal cuff brachytherapy after hysterectomy and chemotherapy for stage IA papillary serous endometrial cancer using a custom printed 2.75 cm diameter segmented vaginal cylinder with a central channel. Patient 2 underwent interstitial brachytherapy for a vaginal cuff recurrence of endometrial cancer after prior hysterectomy, whole pelvis radiotherapy, and brachytherapy boost. We printed a 2 cm diameter vaginal cylinder with one central and six peripheral catheter channels to fit a narrow vaginal canal. Patient 3 underwent interstitial brachytherapy boost for stage IIIA vulvar cancer with vaginal extension. For more secure applicator fit within a wide vaginal canal, we printed a 3.5 cm diameter solid cylinder with one central tandem channel and ten peripheral catheter channels. The applicators were printed in a biocompatible, sterilizable thermoplastic. Results Patient 1 received 31.5 Gy to the surface in three fractions over two weeks. Patient 2 received 36 Gy to the CTV in six fractions over two implants one week apart, with interstitial hyperthermia once per implant. Patient 3 received 18 Gy in three fractions over one implant after 45 Gy external beam radiotherapy. Brachytherapy was tolerated well with no grade 3 or higher toxicity and no local recurrences. Conclusions We established a workflow to rapidly manufacture and implement customized vaginal applicators that can be sterilized and are made of biocompatible material, resulting in high-quality brachytherapy for patients whose anatomy is not ideally suited for standard, commercially available applicators.

Abstract P1-10-03: NSABP B-43 is unlikely to produce a cost-effective treatment strategy for HER2+ DCIS

Background. National Surgical Adjuvant Breast and Bowel Project (NSABP) B-43 is an ongoing randomized clinical trial that compares breast conserving surgery, radiation therapy, and two infusions of trastuzumab to breast-conserving surgery and radiation only for HER2+ ductal carcinoma in situ (DCIS). We sought to identify, from a societal perspective, the level of risk reduction observed in this trial that would be required to make treating HER2+ DCIS patients with trastuzumab cost-effective. Methods. We developed a Markov decision-analytic model to evaluate these treatment strategies in terms of life expectancy, quality-adjusted life years (QALYs), costs, and the incremental cost-effectiveness ratio (ICER) over 15 years. The results of NSABP B-43 are pending. We therefore assumed the hazard reduction to be 36%, based on the statistical considerations of the trial protocol and explored this in sensitivity analyses. A series of one and two-way sensitivity tests were conducted. Results. The baseline ICER for switching from a breast-conserving surgery and radiation strategy without trastuzumab treatment to a breast-conserving surgery and radiation strategy with trastuzumab treatment is

Book review: Early breast cancer: from screening to multidisciplinary management

1.57 million per life-year gained and

Inverse Planned High-Dose-Rate Brachytherapy for Locoregionally Advanced Cervical Cancer: 4-Year Outcomes

299,616.73 per QALY gained. Compared to a societal willingness-to-pay threshold of

Evaluation of Heart Dose for Left-Sided Breast Cancer Patients Over an 11-Year Period Spanning the Transition From 2-Dimensional to 3-Dimensional Planning

100,000 per QALY gained, adding Herceptin treatment is not cost-effective in the treatment of DCIS under these baseline conditions. In a one-way sensitivity test, we found that the Herceptin strategy only became cost-effective at an 88.3% risk reduction for local recurrence. The model was not sensitive to any costs or probabilities within 20% of baseline values. The model was sensitive to the utilities of having had breast-conserving surgery and radiation with and without trastuzumab treatment. It was not sensitive to other utilities within 0.05 of baseline values. Conclusions. High risk DCIS treated with breast-conserving surgery and radiation has a low risk of local recurrence as demonstrated in multiple randomized trials. The addition of a costly drug in order to reduce this small risk further is very unlikely to be cost-effective and could be considered overtreatment of a non-fatal disease that is sufficiently managed with local treatment. Prospective cost-effectiveness analyses have the potential to guide allocation of valuable resources for breast cancer research, and should be regularly integrated into the protocol design of large clinical trials. Citation Format: Michael D Alvarado, Mitchell T Hayes, Rajni Sethi, Elissa Ozanne. NSABP B-43 is unlikely to produce a cost-effective treatment strategy for HER2+ DCIS [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-10-03.

CONSERVATIVE SURGERY AND RADIATION—STAGE I AND II BREAST CANCER

Breast cancer is a profound global health problem, with the majority of breast cancers presenting in early stages in developed countries. With deference to the scope of this problem, the editors of Early Breast Cancer: From Screening to Multidisciplinary Management have developed a comprehensive textbook dedicated to issues relevant to early breast cancer in particular. Topics include estimating breast cancer risk, breast cancer prevention, screening programs, diagnostic evaluation, breast pathology, establishing multidisciplinary teams, and treatment with surgery, systemic therapy, and radiation. Many of the sections in this book focus on organizational structure and the impact of various programs, which give a refreshing and relevant viewpoint to readers today who are concerned not only about scientific principles but also about healthcare delivery in general to large populations of people. Most of the authors of this textbook hail from the UK, with several additional contributors from the USA, Italy, Greece, and Australia. As a result, Early Breast Cancer: From Screening to Multidisciplinary Management takes on a characteristically European bent with a population-level viewpoint that underscores the text and organization. Of the 51 chapters in the book, the first 12 chapters are essentially devoted to breast cancer screening, with many examples from screening programs in the UK. The proceeding section on diagnostic evaluation outlines the major imaging modalities with a strong focus on mammography and lighter overviews of the use of ultrasound, MRI, and PET/CT. After straightforward sections including three chapters on biopsy techniques and five chapters on breast pathology, an entire very interesting section ensues comprising four chapters dedicated to issues in multidisciplinary management of breast cancer from a systems approach, again using examples from the UK. The book winds down with three sections on management with surgery, radiotherapy, and systemic therapy, respectively, followed by a final section dedicated to special circumstances. The 18 chapters in these sections highlight approaches specifically relevant to early stage breast cancer. They are organized with overview chapters intermixed with chapters on individual topics, giving more detailed accounts of novel techniques and controversies relevant to contemporary treatment. To summarize, this is an interesting textbook focused on the epidemiology, work-up, and treatment of early stage breast cancer in the modern era. It is designed to speak to practicing oncologists, generalists, and epidemiologists as well as students of these topics. It is also written at a level that could easily be digested by patients themselves who may have a more academic interest in the disease. This book is unique in that it approaches breast cancer from a population-level vantage point, giving examples of healthcare systems to implement breast cancer prevention, detection, and care. As such, it will be an excellent complement to resources that may delve more deeply into individual patient care by providing a larger framework for breast cancer as a public health problem.