ESTRO 2021 Abstract Book

S1063

ESTRO 2021

The purpose of present study was to compare clinical estimation of disease with findings from MRI assessment in cancer cervix patients undergoing chemoradiation.

Materials and Methods Present prospective study, included 38 histopathologically proven patients evaluated both clinically and radiologically (by MRI) before external radiotherapy (EBRT), before intracavitary application (ICR) and 3 months after treatment completion. Disease extent in terms of thickness(AP), width(transverse) and height(cranio-caudal) of primary lesion, vaginal, parametrial and nodal involvement, rectal and bladder involvement was evaluated. On pre-ICR MRI evaluation, patients having no residual disease were labeled as Group-1, while those with residual disease as Group-2. Results On pre-ICR MRI, 26/38(72.72%) patients fitted into Group-1 and 12/38(27.28%) patients into Group-2. Clinically, 10/38(26.31%) patients had residual lesions. Three months after treatment completion, all patients had complete response, both clinically and radiologically. AP estimation was clinically less in 23/38(60.53%) and more in 15/38(39.47%) patients. Among 23 patients with clinically estimated thickness < MRI assessment, percentage difference was <22% in 16 (42.10 % of 38) and >22% in 07 (18.42% of 38) patients. In none of 15 patients with clinical AP > MRI measurement, difference was >22 % (p=0.029). Width was clinically less in 28/38(73.68%) and more in 10/38(26.32%) patients. Among 28 patients with clinical transverse measurement less than MRI measurement, percentage difference was <22% in 12(31.58 % of 38) and >22% in 16(42.10% of 38). In none of 10 patients with clinical measurement > MRI assessment, difference was >22 % (p=0.002). Cranio-caudal extent was clinically less in 34/38(89.47%) and more in 04/38(10.53%) patients. Among 34 patients with estimation < MRI measurement, percentage difference was <22% in 20(52.63 % of 38) and >22% in 14(36.84% of 38) patients. In none of 4 patients with clinical measurement more than MRI measurement, difference was >22%. Clinically, 11 patients had no parametrial involvement with similar findings on MRI in 2(18.18%). Clinical and MRI findings corroborated in 16/38(42.1%) patients. Clinical detection of bilateral parametrium in 11 patients corroborated with MRI findings in 10/11(90.9%) patients. Clinically, vaginal involvement in 23/38(60.52%) patients was corroborated by MRI. 9/38(23.68%) patients had bladder wall and 5/38(13.15%) patients had rectal wall infiltration. MRI detected pelvic lymphadenopathy in 52.63% patients. Conclusion Clinical assessment underestimate size of tumour in all three dimensions especially cranio-caudally, compared to MRI. Clinical parametrial involvement did not always corroborate with MRI findings. MRI detects pelvic lymphadenopathy, and bladder and rectal wall involvement, which is not possible with clinical assessment. PO-1290 Effect of radiotherapy in addition to surgery in early stage endometrial cancer D. Medenwald 1 , L. Susan 2 , C. Gottschick 3 , V. Dirk 3 1 University Halle-Wittenberg, Department of Radiation Oncology, Halle (Saale), Germany; 2 Martin Luther University Halle-Wittenberg, Department of Radiation Oncology, Halle (Saale), Germany; 3 Martin Luther University Halle-Wittenberg , Department of Radiation Oncology, Halle (Saale), Germany Purpose or Objective To assess the affect of radiotherapy in addition to surgery in early-stage endometrial cancer on a population- based level on cancer-related mortality. Materials and Methods Methods: German Epidemiologic Cancer Registries provided the Robert Koch Institute. We considered FIGO I cases with recorded operative treatment (n=12,718, 2000-2017). We computed hazard ratios (HR) from relative survival models in relation to the mortality of the general population with 95% confidence intervals (CI). Multivariate models were adjusted for age, stage (IA vs. IB), grading and chemotherapy. Radiotherapy included external radiotherapy and brachytherapy. Results Results: Cases with a favorable risk profile (FIGO IA, G1/G2) had a slightly lower survival relative to the general population (FIGO IA: 0.9, G1: 0.91). The proportion of FIGO IA cases was lower in the radiotherapy group (52.6%) vs. cases without radiotherapy (78.6%). Additional treatment with radiotherapy was beneficial in FIGO IB (HR=0.74) and in all histopathological grades, but not FIGO IA cases (HR=0.93) cases. Compared to IA tumors, IB cases had a HR of 1.51 (95% CI: 1.34-1.7). Conclusion Conclusions: Radiotherapy in addition to surgery is beneficial for patients in a FIGO IB stage. Further studies need to address the impact of new techniques and risk assessment. PO-1291 Can we safely lower the RT dose with the use of high dose PF for advanced cervical cancer? M. Kawamura 1 , R. Nakahara 2 , S. Ishihara 3 , Y. Oie 3 , Y. Takase 3 , M. Okumura 3 , J. Ito 3 , T. Ono 3 , Y. Itoh 3 , S. Naganawa 1 1 Nagoya University graduate school of medicine, Radiology, Nagoya, Japan; 2 Nagoya University Hospital, Radiology, Nagoya , Japan; 3 Nagoya University Hospital, Radiology, Nagoya, Japan Purpose or Objective To analyze if concurrent chemoradiotherapy (CCRT) with high dose cisplatin and fluorouracil (PF) can effectively reduce the total dose of radiation dose in the setting of curative intense CCRT to cervical cancer. Materials and Methods Cervical cancer patients treated with PF-CCRT in our hospital between 2006 and 2017 were retrospectively