ESTRO 2020 Abstract book

S454 ESTRO 2020

cardiac radioablation. In this talk, we will identify the patient population at risk, methods for delivery, and early results from our off-label and clinical trial experiences.

SP-0725 Sexual rehabilitation after treatment of gynecological cancer K. Kirchheiner 1 1 Medical University Vienna, Dept. of Radiation Oncology, Vienna, Austria Abstract text Pelvic radiotherapy for gynecological cancer is known to cause adverse physical and psychosocial changes that can lead to sexual functioning problems. According to the ASCO recommendations, it is vital to initiate the discussion about sexual health and dysfunction with the patient at the time of diagnosis, and continue to re-address it periodically throughout follow-up 1 . However, patients and providers are often reluctant to broach the topic, and therefore education and discussion is needed to bring sexual health into mainstream, and optimize quality of life outcomes. Commonly reported sexual problems encountered after treatment of gynecologic cancer are introduced, for which modern sexual rehabilitation strategies are described. Vaginal dryness/atrophy , due to the postmenopausal status after radiotherapy, lead to a lack of lubrication despite sexual arousal. During penile- vaginal intercourse, dry friction can cause micro-tears of the vaginal lining and result in dyspareunia. The application of local estrogen has shown to be highly effective for promotion of epithelial regeneration (provided not a hormone-sensitive tumor) 1 . Vaginal moisturizers support hydration of the vaginal tissue thereby reducing discomfort and pruritus. For all penetrative activities, the use of (water-based) lubricants with no irritating ingredients is recommended 2 . Vaginal adhesions are characterized as an early radiation-induced side effect, caused by the denudation of the vaginal epithelial mucosa. The strategy of regular vaginal dilation, initiated 4-6 weeks after completion of treatment, prevents adhesions by separating the vaginal walls. Providing medically approved dilators is regarded standard of care, not only to maintain sexual function, but also to improve ability to perform, and patient tolerance for, gynecological examinations 3 . As compliance rates with dilation are commonly reported to be low, individualized strategies are sometimes needed 3 . For patients with high reluctance, the overnight insertion of a tampon with vaginal moisturizer can be regarded as minimum requirement to separate the vaginal walls. For patients comfortable with using sexual devices, different vibrators (made of medical silicone) might be helpful to combine the mechanical aspect of dilation with more pleasurable sensations 4 . Modern products offer a variety of sizes, shapes and options for stimulation, for example both vaginal and clitoral 5 . Vaginal shortening/tightening , are the result of long-term fibrotic changes associated with hyalinization, disorganized elastosis, and collagen deposition in the extracellular matrix. These changes are a common cause of dyspareunia 3 . It is widely accepted that regular and long-term vaginal dilation (or penile-vaginal intercourse) will prevent or delay the development of vaginal stenosis 6 . However, the underlying mechanism of stretching the vaginal tissue and therefore promoting epithelial cell growth has not been fully elucidated by now 7 . Hypertonic pelvic floor muscles (PFM) can also contribute to the feeling of tightness and dyspareunia. Additionally, anxiety, stress, or pain often trigger an involuntary tension of the PFM. Exercises to contract and relax the PFM, perineal massage and breathing techniques are helpful to reduce the tension and can prevent secondarily induced vaginismus 2,8 . For patients with an already shortened vagina, sex positions that optimize the

Teaching Lecture: Is it safe to treat central lung lesions with SBRT?

SP-0724 Is it safe to treat central lung lesions with SBRT? N. Haasbeek 1 1 VU University Medical Center, Department of Radiation Oncology, Amsterdam, The Netherlands Abstract text Stereotactic ablative radiotherapy (SABR/SBRT) is the current standard of care for unfit patients with peripheral lung cancer. The dose should be to a biologically equivalent tumor dose of at least 100 Gy prescribed to the encompassing isodose. However, with limited data available, European Society of Medical Oncology (ESMO) guidelines suggest more conventionally fractionated radiotherapy or accelerated schedules for central NSCLC, based on higher toxicity described after ultra-short, especially 3 fraction SABR schedules. However, many elderly, frail patients are unfit for longer schedules of fractionated radiotherapy or even chemo-radiotherapy. Population studies show that up to one quarter receives no anticancer treatment, resulting in short median overall survival. As the requirement for travel for 4-6 weeks to undergo conventional radiotherapy may discourage frail patients, more fractionated SABR regimens have been advocated. These longer SABR schedules using 5-12 fractions have been used for many years in central tumors, with inconsistent results. Results are dependent on the fractionation schedules used, the definition of “central”, and the location of tumors that were accepted in relation to organs at risk (OAR). “Central” tumors are often defined according to a “no fly zone” were the tumor is located within 2 cm of the proximal bronchial tree, but many different definitions of the no fly zone have been used. Recently, the term ‘ultra-central’ has been introduced to describe tumors with the highest risk, where the gross tumor volume (GTV) directly abuts the major airways, or where the planning target volume (PTV) overlaps the trachea or main bronchi. Ultra-central tumors should be distinguished from ‘moderately central’ tumors, which are adjacent to other central structures. SABR of ultra-central tumors may be associated with an increased risk for hemorrhage and strictures of central airways. However, ultra-central tumors may also have an inherent higher tendency of bleeding, irrespective of the type of treatment. The used normal tissue constraints for SABR differ widely between studies, and are mostly based on experience in what appears relatively safe, and not on concrete SABR toxicity data. MRI based real time tracking of normal tissue during treatment with dose accumulation may offer some answers in the near future. Until better toxicity data is available, central and especially ultra- central tumor should be treated with caution, and preferably in trials.

Teaching Lecture: Sexual rehabilitation and management of sexual problems after treatment for pelvic cancer