Abstract Book

S854

ESTRO 37

Conclusion Compared to the mCRPC setting, docetaxel use in HSPC appears more toxic. Steroids and GCSF have been used to mitigate these effects. With the trend towards earlier use of chemotherapy including its use prior to radical radiotherapy in the locally advanced setting, the cost of survivorship is high. It is vital to limit toxicity from systemic treatment so patients can reap the benefits of improved survival. This real world study supports the addition of GCSF to docetaxel to reduce febrile neutropenia. Prednisolone use should also be considered to reduce toxicities and maintain patients’ general wellbeing. EP-1587 Stereotactic Image-Guided Intensity- Modulated Radiotherapy for metastatic prostate cancer patients F. Pasqualetti 1 , M. Panichi 2 , A. Sainato 2 , S. Barbiero 3 , D. Baldaccini 4 , E. Notini 4 , R. Morganti 5 , V. Mazzotti 5 , S. Montrone 2 , F. Matteucci 2 , A. Bruschi 3 , A. Gonnelli 6 , A. Molinari 4 , A. Cristaudo 4 , A. Marciano 7 , F. Cartei 3 , F. Paiar 4 1 Azienda Ospedaliero Universitaria Pisana, Oncology, Pisa, Italy 2 Radiation Oncology, Azienda Ospedaliero Universitaria Pisana, Pisa, Italy 3 Radiation Oncology, Casa di Cura San Rossore, Pisa, Italy 4 Radiation Oncology, University of Pisa, Pisa, Italy 5 Section of Statistics, Azienda Ospedaliero Universitaria Pisana, Pisa, Italy 6 Clinical Oncology, Azienda Ospedaliero Universitaria Pisana, Pisa, Italy 7 Nuclear Medicine, University of Pisa, Pisa, Italy Purpose or Objective To assess tumor local control after treatment with image- guided intensity-modulated (IGRT) stereotactic body radiotherapy (SBRT) in patients with metastatic prostate cancer. Material and Methods From November 2011 to July 2017, 53 patients with metastatic prostate cancer were treated with SBRT at the Radiation Oncology Department of Pisa University Hospital. Data has been recorded prospectively. All lesions were treated with Varian True Beam platform, using flattening filter free x-rais. Twenty-four Gy as single fraction or 27 Gy in three fractions (based on organ at risk constraints) were delivered. All patients had been assessed with 18F-Choline PET/CT before SBRT and systemic therapy has been administered only after the occurrence of more than three synchronous lesions revealed by choline PET/CT. In order to avoid biases related to the administration of systemic therapy, time from SBRT to the last follow up or the beginnings of systemic therapy were used to measure local control length. Site of treated lesions (bone or limph node), delivered dose (24 Vs 27 Gy), treatment plan conformity index, pattern of metastatic disease (oligometastatic versus multimetastatic), prostate cancer status (castration resistant or hormone sensitive) and Gleason Score (three groups: GS 6, GS 7, GS 8-9) were considered in the univariate analysis. Results In October 2017, at data analysis, results concerning 83 treated lesions were recorded (37 bone and 46 node, 32 treated with 24 Gy as single fraction and 51 using 27 Gy in three fractions). After a median follow-up of 23.7 months (range 1-103), only two bone lesions have progressed; 24-month local control was 96%. On univariate analysis, sites of lesions, delivered dose,

[95% CI: 1.20-6.80], p=0.018) were independent prognostic factors for worse OS. Conclusion We found that WPRT as compared with PBRT did not significantly improve bPFS or OS. On the contrary, OS following WPRT was significantly lower than that after PBRT. Our results bring into questions whether second cancers may be increased with WPRT. EP-1586 Docetaxel – Mitigating the high price of success Y.P. Song 1 , S. Morrison 1 , J. Lyons 1 , K. Patel 1 , C. Coyle 1 , P. Elliot 1 , J. Logue 1 , A. Tran 1 , J. Wylie 1 , R. Conroy 1 , A. Choudhury 1 1 The Christie NHS Foundation Trust, Clinical Oncology, Manchester, United Kingdom Purpose or Objective There has been an evolution in the treatment of advanced hormone sensitive prostate cancer (HSPC) with earlier introduction of docetaxel in combination with androgen deprivation therapy (ADT). STAMPEDE showed improved failure-free and cancer specific survival with docetaxel in metastatic and high risk prostate cancer. A higher risk of febrile neutropenia is reported, with rates of 6% to 15% compared to 3% in metastatic castrate resistant prostate cancer (mCRPC) in TAX-327. GETUG- AFU15 mandated the use of granulocyte colony stimulating factors (GCSF). STAMPEDE included the use of prednisolone but CHAARTED did not. This study looks at the rate of toxicity in a tertiary cancer centre, comparing the outcome with the addition of prophylactic GCSF and prednisolone. Material and Methods Data from all HSPC patients treated with docetaxel from June 2015 to June 2017 was collected retrospectively. GCSF has been included as standard from 2016 following a clinical audit in this institution. Patients were divided into groups depending on whether they were prescribed GCSF and/or prednisolone as per clinician discretion. Toxicities were graded with CTCAE version 4. Statistical analysis with chi square test was carried out using SPSS version 25. Results 225 patients were treated during this period. The median age was 67 (44-78). 201 patients had metastatic disease, 20 had node positive cancer and 4 had T3/4N0M0 disease. 64 patients were treated with prednisolone, of which 22 also had GCSF. 156 patients treated without prednisolone had GCSF. The median number of cycles of docetaxel received was 6 (1-6). Prednisolone appeared to have an impact on nausea and maintenance of performance status but the difference was not statistically significant. Fewer patients with prednisolone complained of nausea (4.7% v 10.6% p-value = 0.163) and deterioration in PS following treatment (20.3% v 28.6% p-value = 0.204). 50 (22.2%) patients had dose reductions and 175 (77.8%) were treated at a dose of 75mg/m 2 . A smaller fraction of patients on GCSF had dose-reduced docetaxel but this was not statistically significant (19.7% v 31.9%, p- value=0.072). 31 patients (13.8%) were neutropenic during treatment, of which 25 (10.1%) had febrile neutropenia. There was a higher rate of neutropenia (31.9% vs 9.0%, p-value = 0.00005) and febrile neutropenia (27.7% vs 6.7% p-value = 0.000049) in the non-GCSF group.