ESTRO 37 Abstract book

S31

ESTRO 37

Purpose or Objective Definitive (chemo)radiotherapy, including brachytherapy, is the mainstay of treatment for primary vaginal cancer. Because vaginal cancer is very rare, most studies have included few patients over a long time span and most are from the radiographic era, prior to the use of CT or MRI for brachytherapy treatment planning. The purpose of this study was to assess the outcome of patients who had CT or MRI based image guided adaptive brachytherapy (IGABT) for primary vaginal cancer in a multicenter setting, prior to the development of recommendations for a common target concept. Material and Methods Patients were eligible for inclusion with: a histological confirmed vaginal cancer; FIGO stage I-IVA; MRI at diagnosis; CT or MRI based IGABT (PDR or HDR) with or without chemotherapy. Patients’ charts were retrospectively reviewed to obtain patient, tumor, and treatment characteristics. Late morbidity was scored according to the CTCAE 3.0 scale. The prescription dose, the clinical target volume (CTV) to which this dose was prescribed and the fractionation schedule were according to the local guidelines of each institute. Additionally, organs at risk (OAR) were delineated. Survival rates were calculated using the Kaplan-Meier method and log rank test. Results A total of 148 patients were included from five participating centers. All but three patients, received pelvic EBRT (45-50,4 Gy) and 94 patients (63,5%) received concurrent weekly cisplatin. Twenty-two (15%) patients had FIGO stage I; 65 (44%) II; 42 (28%) III and 19 (13%) IVA. Forty-six (31%) patients had pelvic and/or inguinal lymph node metastases. Median age at time of diagnosis was 63 years (range 24-89). Median follow-up was 29 months (range 3-167). Most patients (78%) were treated with PDR and combined intracavitary plus interstitial brachytherapy (55%). The median volume of the CTV was 17,6 cm3 and the D90 was 80 Gy (52-110Gy). The median doses to the D2cc of the bladder, rectum, sigmoid and bowel were 64 Gy (7-130), 63,5 Gy (22-88), 48,6 Gy (0- 74) and 48,9 Gy (0-74), respectively. At 3 and 5 years, the local control rate was 84% and 82%, respectively, disease free survival was 69% and 65%, respectively and overall survival was 75% and 68%, respectively (Figure 1). Combined crude grade 3/4 bladder and bowel morbidity was 10,8% and grade 3/4 vaginal morbidity was 9,5%. Patients in the group with a T2-4 tumor that received a dose to the CTV of more than 80 Gy had a significant better local control than patients who received less than 80 Gy (Figure 2).

Results The computer-interpretable GL and the flow of patients within the GL is shown in Fig. 2; among the total of 485 patients, 473 patients (97.5%) entered the GL. Of the 473 patients, 354 (75%) reached one of the completion states. By comparing the flows of patients among the three different branches of the GL, it emerged that 54 out of 55 patients (98%) completed the pathA, 270 out of 380 (71%) completed the pathB, and 30 out of 38 (79%) completed the pathC. The single highest dropout rate was found in the condition on concurrent chemotherapy (cCT) agent in pathB, with a value of 74.4% of dropouts (from 371 to 276). Among these 95 patients, 32 (33.7%) dropped out because of missing data about the cCT regimen used, 63 patients dropped out because they underwent to another chemotherapy (not 5-Fluorouracil, not Capecitabine). The waiting time distributions from treatment end to surgery in the 3 paths of the GL didn’t show, as expected, any statistically significant difference (p-value 0.85 for pathA-pathB, 0.71 for pathA-pathC, 0.41 for pathB-pathC).

Conclusion This study shows the potential that a PM approach has in managing patient processes and workflows within a radiation oncology department. It was possible to check and measure the difference between the actual process and the recommended one, exploiting, without additional data management cost, the data already stored in EHR. The level of non-adherence can be then used as a metric of conformance to improve either the actual process execution, the data storage system, or the guideline itself depending on the causes of such deviations from the GL or from the GCP. OC-0070 Image guided brachytherapy for primary vaginal cancer: results of an international multicenter study H. Westerveld 1 , R. Nout 2 , M. Schmid 3 , C. Chargari 4 , N. Nesvacil 3 , R. Mazeron 4 , L. Fokdal 5 1 Academic Medical Center, Radiotherapy, Amsterdam, The Netherlands 2 Leiden University Medical Center, Radiotherapy, Leiden, The Netherlands 3 Comprehensive Cancer Center- Medical University of Vienna, Radiotherapy, Vienna, Austria 4 Gustave Roussy Cancer Campus, Radiotherapy, Villejuif, France 5 Aarhus University Hospital, Oncology, Aarhus, Denmark Proffered Papers: BT 1: Gynaecological brachytherapy