ESTRO 38 Abstract book

S335 ESTRO 38

should all be considered to minimize the risk of CVM, when treatment options of brachytherapy and/or EBRT are discussed according to risk groups. PV-0629 Late toxicity and PROMs in pelvic or prostate RT in high risk prostate cancer: A randomized trial. V. Murthy 1 , J. Bhatia 2 , S. Kannan 3 , P. Gurav 2 , R. Krishnatry 2 , D. Chourasiya 3 , G. Prakash 4 , G. Bakshi 4 , S. Menon 5 , U. Mahantshetty 2 1 Advanced Center for Treatment- Research and Education in Cancer, Radiation Oncology, Mumbai, India; 2 Tata Memorial Center- HBNI, Radiation Oncology, Mumbai, India ; 3 Advanced Center for Treatment- Research and Education in Cancer, Cancer Research Secretariat, Mumbai, India ; 4 Tata Memorial Center- HBNI, Surgical Oncology, Mumbai, India ; 5 Tata Memorial Center- HBNI, Pathology, Mumbai, India Purpose or Objective The benefit of whole pelvis radiotherapy in node negative, high-risk prostate cancer is uncertain. While oncological outcomes of whole pelvis (WPRT) and prostate only (PORT) radiotherapy are awaited from ongoing trials, we present the toxicities and patient reported outcomes measures (PROMs) from a randomized controlled trial. Material and Methods This single institution randomized controlled trial was conducted in node negative, high-risk adenocarcinoma prostate with an estimated nodal risk (Roach) of over 20%. Patients were randomized using stratified block randomization based on history of TURP (yes vs no), Gleason score (6-7 vs 8-10) and PSA levels (<50 vs>50). All patients received at least 2 years of androgen deprivation therapy and hypofractionated, daily image guided, intensity modulated radiotherapy to a dose of 68Gy in 25 fractions to prostate (2.72Gy/#) with 50Gy in 25 fractions to the pelvic nodes including the common iliac region in WPRT arm using simultaneous integrated boost. Late gastrointestinal (GI) and genitourinary (GU) toxicities (RTOG scale), PROMs (EORTC QLQ C-30 and PR 25) were documented at pre-treatment and every 3-6 months post treatment. Results A total of 224 patients were randomized to WPRT (n=110) and PORT (n=114) arms. Both the arms were well balanced for patient and disease characteristics. Median follow up was 37 months. Both the treatment arms were well tolerated with less than 3% actuarial grade III GI and GU toxicities and no grade IV toxicities (Table 1). Actuarial grade II or higher late GI toxicities were similar in both arms (Hazard Ratio = 1.81; 95% CI = 0.49 -6.61; p = 0.36), whereas late GU toxicities (grade II or higher) were significantly worse in WPRT arm (Hazard Ratio = 2.96; 95% CI = 1.25 – 7.03; p = 0.01) (Table 1; Figure 1a and 1b). A total of 217 patients (WPRT = 112; PORT = 105) completed 1068 questionnaires, with a median assessment time of 11 months (Range = 2 – 73 months). Each patient completed a mean of 5 assessments. Mean scores for global, bowel, urinary symptoms or any other domain were clinically or statistically no different between the two arms.

Conclusion This is the first randomized trial addressing the question of pelvic RT in patients with high risk, node negative prostate cancer using modern image guided radiotherapy and moderate hypofractionation. At a median follow up of 3 years, there were low grade III toxicities in both arms. Grade II GU toxicity was higher with WPRT while the GI toxicities and the PROMs were similar in the two arms. PV-0630 10-year multi-centre experience of adjuvant radiotherapy in pN3 squamous cell carcinoma of the penis

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Award Lecture: Donald Hollywood award lecture

OC-0631 Stem cell sparing IMRT for head and neck cancer patients: a double-blind randomized controlled trial R. Steenbakkers 1 , M. Stokman 1 , R. Kierkels 1 , M. Schuurman 1 , A. Van den Hoek 1 , H. Bijl 1 , M. Dieters 1 , R. Coppes 2 , J. Langendijk 1 , P. Van Luijk 1 1 UMCG University Medical Center Groningen, Radiation Oncology, Groningen, The Netherlands ; 2 UMCG University Medical Center Groningen, Radiation Oncology - Cell Biology, Groningen, The Netherlands Purpose or Objective Head and neck cancer patients treated with radiotherapy often suffer from xerostomia. Critical for the radiation response of the parotid glands are the parotid gland stem cells, mainly located in the main salivary gland ducts (van Luijk, 2015). Reducing dose to these High Stem Cell Density (HSCD) regions may prevent xerostomia. This double-blind randomized controlled trial (RCT) aimed to determine the impact of dose reduction to the HSCD regions on parotid gland stimulated salivary flow

Table 1 - Actuarial Late Toxicities

GI - Overall - n = 224 (%)

GI - WPRT - n = 110 (%)

GI - PORT - n = 114 (%)

GU - Overall - n = 224 (%)

GU - WPRT - n = 110 (%)

GU - PORT - n = 114 (%)

p value

p value

I 52 (23.3) 28 (26.7) 24 (23.1) 0.92 86 (38.6) 39 (37.1) 47 (45.2) 0.02

II 9 (4)

5 (4.8) 4 (3.8)

22 (9.9) 16 (15.2) 6 (5.8)

III 1 (0.4)

1 (1)

0 (0)

5 (2.2)

3 (2.9) 2 (1.9)