ESTRO 2020 Abstract Book

S507 ESTRO 2020

PO-0949 Maximising patient access to advanced breast radiotherapy techniques and personalised radiotherapy P. Kechagioglou 1 , T. Williams 2 , M. Bowler 1 1 GenesisCare UK, oncology, Windsor, United Kingdom ; 2 GenesisCare UK, Oncology, Birmingham, United Kingdom Purpose or Objective Breast conserving surgery is the standard surgical procedure to treat breast cancer in UK and globally. Whole breast radiotherapy post operatively reduces the incidence of ipsilateral breast cancer recurrence by almost 20% (Veronesi, 2001) and reduces 15-year mortality from breast cancer by 5.4% (Ernster, 2000). Access to advanced radiotherapy has been lagging behind demand in UK NHS across all cancers, for reasons including workforce shortage, time pressures for complex planning and inconsistent peer review processes (Round 2012). Partial breast irradiation (PBI) reduces skin side effects while offering same protection as whole breast radiotherapy (Coles, 2017), simultaneous Integrated Boost (SIB) shortens treatment times while offering better tumour bed control that sequential boost (Van Parijs, 2014) and regional nodal irradiation (RNI) with VMAT IMRT provides excellent target dose conformity in high risk risk patients (Ranger, 2018). Material and Methods A review of breast cancer cases referred for advanced radiotherapy techniques over a 6-month period between November 2018 and May 2019 was conducted and correlated with patient eligibility for those techniques (PBI, SIB and RNI). The uptake of those techniques has not been consistent across the network and the purpose of this study is to identify patient eligibility, measure technique uptake and devise strategy to increase patient access to advanced radiotherapy. Minimum patient datasets, histologies, imaging reports and multi-disciplinary team meeting outcomes were reviewed from our electronic patient medical record (Mosaiq EMR, Elekta). Results 408 breast radiotherapy cases were recorded over a 6- month period across our 12 UK centres and 39 of those were treated at our Oxford and Cambridge centres, the centres we based this study on. Two patients had palliative breast radiotherapy and one had radiotherapy for DCIS and they were excluded. The uptake of advanced radiotherapy techniques compared to eligible patients in the remaining 36 patients is shown in table 1.

steps to maximise our internal capabilities and we have changed clinical practices. PO-0950 Tissue Doppler and Strain Echocardiographic Indices of heart after PMRT in Breast Cancer Patients S.A. Javadinia 1 , S. Shahidsales 2 , K. Anvari 2 , H. Gholamhosseinian 2 , F. Ghaderi 3 1 Student Research Committee, Sabzevar University of Medical Sciences, Sabzevar, Iran Islamic Republic of ; 2 Mashhad University of Medical Sciences, Cancer Research Centre, Mashhad, Iran Islamic Republic of ; 3 Mashhad University of Medical Sciences, Department of Cardiology, Mashhad, Iran Islamic Republic of Purpose or Objective This study aimed to evaluate the heart dose and assess its association with tissue Doppler and strain echocardiographic indices after adjuvant chest wall radiotherapy in patients with breast cancer. Material and Methods In Omid Hospital and Imam Reza Hospital of Mashd, Iran, patients with breast cancer candidate for adjuvant radiotherapy of chest wall after mastectomy were enrolled. All patients underwent strain and Tissue Doppler echocardiography before adjuvant radiotherapy. Radiotherapy was prescribed using LiNAC after 3D conformal planning with a total dose of 50Gy/2Gy (figure 1). Six and twelve months after completion of radiotherapy, strain and Tissue Doppler echocardiography was repeated. Changes in echocardiographic indices and its association with DVH of heart during treatment were analyzed at P level less than 0.05.

Results Thirty-one patients with mean age 36.6±4.6 years were enrolled. Most patients received AC-T regimen (74.2%, 23) with cumulative doxorubicin and trastuzumab doses of 237±25 mg/m 2 and 107.8±18.5 mg/kg, respectively. Correlation between heart dose variables during radiotherapy with echocardiographic changes revealed a significant reverse correlation between the minimum heart rate and the TAPSE changes at 6-month (p=0.04, r=- 0.3), maximum heart dose with RV strain changes at 6- month (p=0.04, r=-0.3) and S' changes at 6-12 month (r = 0.02, p=0.04, p =0.05, r=0.3), V30 with E-velocity changes at 6-12 month (r=-0.05, p=0.02, r=-0.4) and V20 with Evelocytic changes at 12-month (p=0.04, r=- 0.03). The RV strain in 12 patients (38.7%) with normal function became impaired after 6 months (p = 0.004). The univariate analysis showed that with increasing the V30 heart rate, Sm at 6-12 months were significantly reduced by 0.2% (p = 0.05). Also, with an increase in in the maximal heart dose, TAPSE at 6 month decreased significantly by 0.01 (p = 0.05). No case with clinical cardiac disease was not observed (figure 2).

Eligible and Offered (%)

Eligible not offered (%)

Eligible (%)

Not eligible

Technique

Partial Breast Irradiation Simultaneous Integrated Boost Regional Nodal Irradiation

12 (33) 1 (8)

11 (92) 24 (67)

15 (42) 3 (20)

12 (80) 21 (58)

5 (14) 5 (100)

0

31 (86)

Only 1 out the 11 eligible patients was offered PBI. The single patient who received PBI had zero RTOG toxicity. One patient who did not receive PBI developed grade 4 toxicity. 36% of patients had grade 2 and 45% had grade 1 toxicity. 100% of high-risk patients were treated with VMAT IMRT RNI but only 20% of patients who were eligible for a breast boost were offered SIB. Conclusion At GenesisCare UK, we set out our vision for the Breast Service of the Future, an approach that draws from best practice which includes evidence-based advanced radiotherapy. We believe that patients should be offered a personalised approach to radiotherapy. We have taken