ESTRO 2020 Abstract book

S455 ESTRO 2020

angle/depth of penetration, and allow for maximum movement control by the woman can be helpful 9 . Additionally, a “pain buffer” (soft silicone rings placed at the shaft of the penis) can adapt the length of the penis in cases of deep dyspareunia, and reduce anxiety to prevent a vicious circle of pain. The woman´s arousal and in particular orgasm before penetration (by masturbation or foreplay) can also reduce dyspareunia. The increased vaginal blood flow improves tissue oxygenation and might therefore enhance vaginal elasticity 10,11 . Additionally, relief of PFM tension and mental relaxation might both facilitate painless penetration. Loss of desire has multifactorial physical and psychological reasons and is often complex to diagnose and treat. Basic strategies include the provision of self-help educational material 12 and options for referral to specialists (nurses/psychologists with training in sexual health). Psychosocial education/counselling can be effective strategies for concerns regarding body image, intimacy/relationship, sexual functioning and satisfaction; and consideration should be given for including a women’s partner 1 . In a specialized sexual therapy setting, several evidence-based interventions have been proven to be effective, such as the sensate focus exercises (graded series of non-demand sensual touching exercises), experimenting with different sensations and stimuli within mindfulness-based approaches and cognitive-behavioral therapy (identifying and altering cognitions and behaviors that contribute to low sexual desire) 13 .

Negative emotional states such as anxiety, depression, anger may also disrupt sexual activity. Prostate cancer is the most frequent non-skin male malignancy in Western countries. Radiation therapy is together with radical prostatectomy the most effective treatment for localized disease. Both external-beam radiotherapy (EBRT) and brachytherapy can be offered as curative options. Published rates of erectile dysfunction (ED) following EBRT vary from 7–80%, and after brachytherapy this percentage may be as high as 60%. The etiology of ED after radiation of prostate cancer is multi- factorial. Vascular, neurogenic and psychogenic factors are often reported, though a vascular mechanism seems more likely to be involved. Sildenafil and tadalafil are effective to treat ED in about half of the patients after radiotherapy. Testicular cancer affects more often young men in their fertile and sexually active life. In our survey, about 20% of the patients reported less sexual interest, pleasure and activity since treatment, and this was not significantly correlated with age. Though, these percentages were not different from an age-matched control group of men without testicular cancer. Fifteen per cent of the patients had ED. Sixty-two per cent found their body had changed after treatment. In general, reported sexual function soon after treatment indicates high levels of sexual dysfunction that tend to improve over time. More than half of testicular cancer patients reported that their body image had changed after treatment. Carcinoma of the penis is a rare malignancy. Most patients can still enjoy a sexual life if laser treatment is used, but more invasive procedures reduce this likelihood. The stability of sexual function in husbands and wives of cancer patients suggests that the sexual problems in these patients are caused by the emotional and medical impact of the illness as by the stress in the couple’s relationship. Patients need to be adequately counselled on the effects of cancer treatment on their sexual life and relationship, about the different treatment possibilities and reassured of being able to enjoy a normal sexual life. Unfortunately, sexual counselling has not become a routine part of oncology care in most hospitals, but this should be routinely provided. SP-0727 Dosimetry and QA for MR-Linacs B. Van Asselen 1 , S.L. Hackett 1 , S.J. Woodings 1 , B.W. Raaymakers 1 , J.W.H. Wolthaus 1 1 university Medical Center Utrecht, Department Of Radiation Oncology, Utrecht, The Netherlands Abstract text The excellent visualization of soft-tissue with MRI allows direct visualization of the tumor when applied during the delivery of radiotherapy. Several MRI guided systems have been developed, which combine MRI with an accelerator: the MRidian (Viewray Technolgies Inc, USA) and the Unity (Elekta AB, Sweden). The latter system was developed together with the UMC Utrecht. In high- precision MRI-guided radiotherapy, the treatment dose is delivered in a magnetic field. In both designs the dose is delivered in a transverse magnetic field of respectively 0.35 T and 1.5 T for the MRIdian and Unity systems. In a magnetic field, dose deposition is affected by the high magnetic field and therefore dosimetry and QA guidelines for conventional radiotherapy do not apply. Teaching Lecture: Dosimetry and QA for MR-Linacs

SP-0726 Sexual rehabilitation and management of erectile dysfunction after treatment for male pelvic cancer L. Incrocci 1 1 Erasmus Medical Center Rotterdam, Department of Radiation Oncology, Rotterdam, The Netherlands Abstract text Sexual dysfunction is often unrecognized, underestimated and untreated. Sexual dysfunction is one of the more common consequences of cancer treatment. Sexual dysfunction in cancer patients may result from biological, psychological and social factors. Biological factors such as anatomic alterations (rectum or penile amputation), physiological changes (hormonal status) may preclude normal sexual functioning even when sex desire is intact.