ESTRO 38 Abstract book

S855 ESTRO 38

lymphadenectomy. We have progressively increased the dose delivered to the prostate bed from 66 to 71 Gy. In patients with visible recurrence, we registered the mpMRI and the simulation CT images to define a recurrence and to intensify the dose on it. The series include the first 25 pt treated with IMRT and moderate hypofractionation (2.1 to 2.35 Gy per fraction). For the analyses, total doses were converted into 2Gy-equivalent doses (EQD2) according to the linear quadratic model taking alfa/beta=1.5 for the tumor and alfa/beta=3 for bladder. Acute and late toxicity were scored according to the RTOG and CTCAE v4.0 scales. We have investigated the association among the dosimetric parameters and toxicity. Results The multiparametric-MRI was positive in 79 pt (41.5%). Local recurrences were mostly located at the perianastomotic site. Lymph node recurrence occurred in 22 pt (11.5%). Median radiation doses (Gy) for pt treated with normofractionation were: 70.2 (64-71) in prostate bed, 73.8 (71-76) on local recurrence location, and 60.90 (56-75.2) on positive lymph nodes. The doses for hypofractionation were: 65 (63.8-70.2) in prostate bed, 68.5 (63.8-70.2) on local recurrence location and 60.9 (58.8-62.35) on positive lymph nodes. With a median follow-up of 40 months (2-75 months) 75% of pt showed biochemical and clinical control. We observed acute grade 2-3 GU toxicity in 3pt (3.2%). Grade 2, 3 and 4 GU late toxicity (mainly haematuria) was observed in 9 (5.1%), 7 (3.9%) and 1 (0.5%) pt respectively. Late haematuria grade ≥2 was higher in those patients with mean bladder dose > 50 Gy (10.8% vs 1.4%; p= 0.017) and/or bladder V70 > 30 Gy (20.8% vs 2.3;p < 0.001). None of the patients treated with IMRT showed late grade ≥2 haematuria. Conclusion We recommend a very strict evaluation of bladder dose- volume histogram to decide whether or not to intensify the radiation dose after prostatectomy. EP-1584 Radium-223 treatment in Metastatic Prostate Cancer: Prognostic Factors: Real-world Outcome R. Pearson 1 , X. Jiang 1 , S. Atkinson 2 , S. Cumming 1 , A. Burns 3 , J. Frew 1 , R. McMenemin 1 , I. Pedley 1 , A. Azzabi 1 1 Newcastle upon Tyne Hospitals NHS Foundation Trust, Northern Centre for Cancer Care, Newcastle upon tyne, United Kingdom ; 2 Newcastle upon Tyne Hospitals NHS Foundation Trust, Dept of Nuclear Medicine, Newcastle upon tyne, United Kingdom ; 3 Newcastle upon Tyne Hospitals NHS Foundation Trust, Dept of Radiotherapy Information Technology, Newcastle upon Tyne, United Kingdom Purpose or Objective Radium 223 (Ra-223) is a radiopharmaceutical used to treat men with metastatic castrate resistant prostate cancer (mCRPC) with symptomatic bone metastases. We aim to evaluate factors impacting survival outcomes from a heterogeneous cohort of 228 patients treated in a single UK centre. Material and Methods We prospectively collected data from 228 men underwent Ra-223 therapy for mCRPC between April 2014 and August 2018. Survival outcomes were analysed and prognostic factors were extracted. Results Medium age = 72 (51-87) years. Most patients (90.3%) whose baseline haemoglobin > 10g/dl (n=160) managed to complete 5-6 cycles of treatment in contract to 13.2% if it was 8-10 g/dl (n=19) or 0% if < 8 g/dl (n=4). Key findings are summarised in table below.

160 (70.2%) 15.7 53 (23.2%) 7.8 32 (14%) 28 64 (28.1%) 5.9 67 (29.4%) 5.4 107 (46.9%) 13.5 80 (35.1%) 8.4 49 (21.5%) 19.5 27 (11.8%) 15.8 112 (49.1%) 8.9 144 (63.2%) 15.8 62 (27.2%) 4.7 33 (14.5%) 25.1 152 (66.7%) 10.5 84 (36.8%) 17.5 85 (37.3%) 8.6 161 (70.6%) 13 22 (9.6%) 5

PS 0-1

<0.0001 0.38 0.24 - 0.6

PS >2

<0.0001

No of mets <6

<0.0001

No of mets 6-20

<0.0001

No of mets >20

<0.0001

0.39 - 0.83

Baseline ALP <220

0.0014

0.57

Baseline ALP >220

0.0014

Baseline Hb >/= 10

<0.0001 0.32 0.15 - 0.7

Baseline Hb <10

<0.001

Baseline PSA <50

0.006

Baseline PSA 50-100

0.006

Baseline PSA >100

0.006

Cycles completed 5-6

<0.0001 0.25 0.15 - 0.4

Cycles completed 1-4

<0.0001

0.34 - 0.77

PSA fall /= 30%

0.0066

0.51

PSA other

0.0066

0.35 - 0.75

Neutrophil/lymphocyte ratio post Ra223 <3.89 Neutrophil/lymphocyte ratio post Ra223 >/= 3.89

0.0005

0.52

0.0005

Conclusion Our data showed patients with fewer metastases, completion of 5-6 cycles of Ra-223 and those who had PSA reduction of 30% or more at the end survive significantly longer. Fitness but not age was significant. Lower baseline ALP, PSA, neutrophil/lymphocyte ratio and higher baseline haemoglobin are positive prognostic biomarkers for survival.

Electronic Poster: Clinical track: Urology-non-prostate

EP-1585 Modified BEP chemotherapy regimen in testicular germ cell tumors: Outcome and toxicity N. Thakur 1 1 Post Graduate Institute of Medical Education and Research, Radiotherapy and Oncology, Chandigarh, India Purpose or Objective Bleomycin ,Cisplatin and Etoposide (BEP) is established as standard treatment for Testicular Germ cell Tumours. Standard BEP regimen consist of Bleomycin 30 IU DAY 1,8 and 15, cisplatin 20 mg/m2 day1-5 and etoposide 100 mg/m2 day1-5. As these tumours are highly curable ,so management is crucial in terms of long term toxicity particularly lung toxicity. With standard BEP there is increased toxicity which leads to poor compliance so we at a tertiary care centre assessed modified BEP regimen in such patients and evaluated its effectiveness in terms of response and toxicity as compared to standard BEP. The original intent is to explore the cost-effectiveness and improved patient compliance of this modified protocol without losing efficacy in treatment. Material and Methods Forty nine patients of testicular tumours were enrolled in this study from January 2012 to December 2016. Of them, 43 patients were of non-seminomatous germ cell tumor

Median Survival (mths)

p-value (log rank)

HR (log rank)

Patient No (%)

95% CI

Variables

Overall

228

11.1

n/a

n/a

n/a