ESTRO 36 Abstract Book

S371 ESTRO 36 _______________________________________________________________________________________________

patients had histologically proven non-metastatic ASCC and all underwent curative CRT. There were no statistically significant differences between the test and replication cohorts in terms of baseline demographics and cancer characteristics. The majority of patients had advanced staged disease at presentation - 28/40 patients in the test cohort and 23/30 were AJCC stage III (IIIA or IIIB).11/40 patients in the test cohort and 7/30 patients in the replication cohort experienced disease recurrence. Median follow-up was 25 months.Using the test cohort, we identified seven baseline TA parameters that were the most influential predictors of disease recurrence at baseline (Figure 1) with FDR p-value <0.15 (<0.02 unadjusted). These parameters were then independently tested using the replication cohort, with four out of seven parameters retaining statistically significant predictive value with replication FDR p-value <0.05. Finally, a pooled analysis of data showed yielded a highly significant FDR p- value <0.01 for five out of seven TA parameters tested.

Netherlands specialised in gynaecological oncology. The survey addressed important factors that might influence treatment outcome after external beam radiotherapy (EBRT) and brachytherapy (BT): the definition of target volumes, treatment preparation, imaging for treatment planning, treatment planning and IGART for EBRT and BT. Results All Dutch centres follow and meet the recommendations from the (inter)national guidelines. Within the freedom of the guidelines, we found differences between centres that may have a clinical impact, among others: differences in fractionation size and total dose (with an EQD2 for normal tissue after EBRT varying between 43 and 50 Gy), when or whether to use PET-CT imaging depending on availability of equipment, if para-aortic lymph nodes should be included in the CTV or not, and which technique is used to reduce the dose in OARs (i.e. whether to use box-fields, arc-rotation therapy, IMRT or IGART with a plan of the day strategies), if and when interstitial needles where used for BT, and whether brachytherapy was guided by CT or MRI.

Conclusion Most differences in radiation practice for cervical cancer are found at the cutting edge of clinical evidence. The majority of these uncertainties are being addressed in current and future (inter)national studies. For instance, to improve uniformity, the LPRGT organized workshops for all Dutch gynaecologic radiation oncologist, who are encouraged to uniformly treat patients and report outcome within the international EMBRACE II study.

Conclusion Quantitative MR based TA parameters, in particular those previously associated with active inflammation, show promise in assessing the risk of anal cancer recurrence at baseline. Poster: Clinical track: Gynaecological (endometrium, cervix, vagina, vulva) PO-0708 Patterns of Care in the Netherlands for Radiotherapy of Women with Locally Advanced Cervical Cancer P. De Boer 1 , I.M. Jürgenliemk-Schulz 2 , W. H. 1 , A.C.C. De Leeuw 2 , R. Dávila-Fajardo 2 , C.R.N. Rasch 1 , B.R. Pieters 1 , L.J.A. Stalpers 1 1 Academic Medical Center, Radiation Oncology, Amsterdam, The Netherlands 2 University Medical Centre Utrecht, Radiation Oncology, Utrecht, The Netherlands Purpose or Objective International guidelines as well as the GEC-ESTRO recommendations and ICRU-89 report encourage progression to more advanced techniques, while achieving a uniform registration and reporting of radiotherapy. Do we meet the present clinical standard in cervical cancer radiotherapy? Therefore, supported by the Dutch National Platform for Radiotherapy of Gynaecological Cancer (LPRGT), we investigated the possible variation in current practice for cervical cancer amongst the Dutch radiation oncology centres specialised in gynaecological oncology. Material and Methods A structured patterns of care questionnaire was completed during a face-to-face interview with radiation oncologists from all sixteen radiotherapy centres in the

PO-0709 Disease courses in women with residual tumor after concurrent chemoradiotherapy for cervical cancer Y.S. Kim 1 , S. Byun 1 , J. Nam 2 1 Asan Medical Center- Univ of Ulsan, Radiation Oncology Department, Seoul, Korea Republic of 2 Asan Medical Center- Univ of Ulsan, Obstetrics and Gynecology, Seoul, Korea Republic of Purpose or Objective To investigate the disease course and identify prognostic factors for survival in patients with residual disease according to post-treatment magnetic resonance imaging (MRI) following definitive concurrent chemoradiotherapy (CCRT) for locally advanced cervical cancer. Material and Methods We reviewed clinical data from the medical records of 545 consecutive women with biopsy-proven, International Federation of Gynecology and Obstetrics stage IB2–IVA uterine cervical cancer treated with CCRT. Post-