Abstract book - ESTRO meets Asia

S106 ESTRO meets Asia 2018

Material and Methods 16 (13 male, 3 female) patients treated radically with concurrent chemo-radiotherapy were included in this retrospective study. The bladder was contoured on the original radiotherapy planning (RTP) scan, cone beam computed tomography (CBCT) at fraction 1 and a further CBCT towards the end of treatment. The distance in which the bladder walls had moved from RTP scan was measured in the anterior, posterior, superior, inferior, left and right directions. The average movement in each direction is then compared using SPSS v25 Results There is bladder wall movement in all directions. The difference in movement between male and female patients is greatest in the posterior direction. In female patients, the average movement posteriorly ranged from 0.37cm at first fraction to 1.23cm at later fractions while in male patients, this remained relatively stable. There was no marked difference in movement of male and female bladders in other directions. Conclusion It is important to consider organ motion so as to deliver radiotherapy accurately. As the bladder sits amongst other pelvic organs, it is vital to consider the difference between male and female pelvis. The presence of a mobile uterus can easily affect bladder position between each fraction of treatment, and similarly the comparatively less mobile prostate posteriorly may account for the marked reduction in posterior motion of a male bladder. This study provides preliminary results when exploring the different way bladders may behave in male and female pelvis. Data collection continues in order to increase the sample size and determine whether a significant association exist. PO-258 Experience of peer reviewed pediatric radiotherapy at a tertiary care university hospital in LMIC B.M. Qureshi 1 , A.N. Abbasi 1 , A. Waheed 1 , S. Abrar 1 , N. Ali 1 , A. Hafiz 1 , B.M. Khan 1 , M.A. Mansha 1 1 Aga Khan University, Radiation Oncology Section- Department of Oncology, Karachi, Pakistan Purpose or Objective Radiation therapy for pediatric tumors is not well emphasized in developing countries. Although the role of radiotherapy in pediatric tumors is decreasing, it still plays a vital role in malignancies arising from central nervous system (CNS), Rhabdomyosarcoma (RMS) and Hodgkin’s’ disease. We aim to share the experience of peer reviewed radiation therapy for pediatric experience at a tertiary care university hospital in Pakistan. Material and Methods Hospital and departmental records of radiation oncology at The Aga Khan University since 2006 was to be explored. All the children seen in radiation oncology clinic are referred through pediatric oncologist along with the treatment protocol. Radiation therapy is planned and delivered after peer review of contours and treatment plans by team of radiation oncologists and residents. Mandatory double check of the treatment parameters is done by a second physicist. Radiation therapy technologist does pre-treatment quality assurance checks before starting treatment for reproducibility of the treatment plan and weekly during radiotherapy, mostly under general anesthesia. Results Hospital cancer registry data was available from 2009 till 2014 only during which 165 patients received radiotherapy. Most common site was brain with 49 (30%) patients with 43 of them having primary CNS tumors. Radiation was given for orbital lesions in 21 (13%) patients out of which 14 had retinoblastoma. Radiotherapy was Clinical: Paediatric tumours

in 27 cases (17 had bilateral, 10 had unilateral nodes). One patient had M1 disease at diagnosis. 46 patients underwent upfront surgery (34 partial penectomy, 9 total penectomy, 3 unknown) while one had extensive unresectable loco-regional disease. Lymph nodes were addressed surgically in 20 of the operated cases (18 had inguinal dissection, 16 with iliac dissection and 2 with sentinel lymph node biopsy). Of the cases that underwent nodal dissection 11 had bilateral and 7 had unilateral dissection. 10 patients were planned for adjuvant radiotherapy of which only 6 completed the intended course. 2 patients had received brachytherapy for locally recurrent disease after definitive surgery (1 patient with mold-based and the other with flexible catheter based interstitial brachytherapy). 13 cases received palliative radiotherapy (including one treatment-default) to the recurrent inguinal nodes. Only 4 patients received adjuvant chemotherapy and one patient defaulted treatment during neoadjuvant chemotherapy. The earliest recurrence was recorded at 30 days post-surgery and the earliest death was recorded 91 days post-surgery. The median DFS was 8 months and median OS was 14 months. The DFS and OS were 33.3%, 20.8% (at 1 year) and 72.9%, 41.6% (at 2 years) respectively.

Conclusion DFS and OS of the penile cancer patients in our study are poor. Our patient population was younger than most of the other studies and have presented in advanced stage of the disease. PO-257 Gender Inequality In Bladder Motion Y.P. Song 1 , E. Vasquez Osorio 2 , A. McWilliam 2 , A. McPartlin 1 , A. Choudhury 2 1 The Christie NHS Foundation Trust, Clinical Oncology, Purpose or Objective The central challenge in delivering bladder radiotherapy is in accurately predicting bladder motion. The shape, size and position of the urinary bladder is affected by internal pressure from bladder filling and external pressure from other pelvic organs. In order to account for bladder motion, a relatively large margin is added to the clinical target volume. This results in potentially increased dose of radiation to normal tissue when the bladder is small and inadequate coverage of the bladder when it is big. Various studies have looked into bladder motion during a course of treatment. However, little is known about the variability in bladder motion in male and female pelvises. We hypothesise that there is no difference in bladder movement in male and female pelvis. Manchester, United Kingdom 2 University of Manchester, Radiotherapy Related Research, Manchester, United Kingdom