ESTRO 36 Abstract Book

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S161 ESTRO 36 2017
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Conclusion
Arm function in patients treated with ALND was worse
compared to patients without ALND. Patients reported
significant more arm symptomatology after ALND followed
by local RT compared to non-ALND patients treated with
local RT and axillary irradiation in the first 3 months after
start of RT. Updated results on PROMs with increased
patient numbers, longer follow-up and multivariable
analyses will be available at the 36th ESTRO conference.
SP-0314 Partial breast radiotherapy after breast
conservation: 5 year outcomes from the IMPORT LOW
(CRUK/06/003) phase III trial
C. Coles1, C. Griffin2 , A. Kirby3, R. Agrawal4, A. Alhasso5,
I. Bhattacharya 2, A.M. Brunt6, L. Ciurlionis7, H. Chan8, E.
Donovan3, M. Emson2, A. Harnett 9, J. Haviland2, P.
Hopwood 2, M. Jefford10, R. Kaggwa2, E. Sawyer11, I.
Sybdikus12, Y. Tsang13, D. Wheatley14, M. Wilcox15, J.
Yarnold16, J. Bliss2
1 Cambridge Cancer Centre, University of Cambridge,
Cambridge, United Kingdom
2 Clinical Trials and Statistics Unit, Institute of Cancer
Research, London, United Kingdom
3 Royal Marsden NHS Foundation Trust, Department of
Radiotherapy, London, United Kingdom
4 Shrewsbury and Telford Hospitals NHS Trust, Oncology
Department, Shrewsbury, United Kingdom
5Beatson West of Scotland Cancer Centre, Oncology
Department, Glasgow, United Kingdom
6Royal Stoke Hospital, Oncology Department, Stoke-on-
Trent, United Kingdom
7Aukland Hospital, Physics Department, Aukland, New
Zealand
8Nuffield Health Cheltenham Hospital, Department of
Surgery, Cheltenham, United Kingdom
9Norfolk and Norwich University Hopsitals NHS
Foundation Trust, Oncology Department, Norwich,
United Kingdom
11Kings College London, Oncology Department, London,
United Kingdom
12Clatterbridge Cancer Centre, Oncology Department,
Bebington, United Kingdom
13Mount Vernon Cancer Centre, Radiotherapy
Department, Northwood, United Kingdom
14Royal Cornwall Hospital, Oncology Department, Truro,
United Kingdom
15Independent Cancer Patient Voice, London, United
Kingdom
16Institute of Cancer Research, Academic Department of
Radiotherapy, London, United Kingdom
Background: Local cancer relapse rates after breast
conservation surgery followed by radiotherapy have fallen
sharply in many countries with risk influenced by patient
age and clinico-pathological factors. In women at lower
than average risk of local relapse, partial breast
radiotherapy restricted to the vicinity of the original
tumour is hypothesised to improve the balance of
beneficial versus adverse effects compared with whole
breast radiotherapy.
Methods: The IMPORT LOW trial (ISRCTN12852634)
recruited women aged ≥50 years after breast conserving
surgery for invasive ductal adenocarcinoma pT≤3cm, pN0-
3, G1-3 and ≥2mm resection margins. Using 15 daily
treatments, patients were randomly allocated (1:1:1) to
40 Gy whole breast radiotherapy (control), 36 Gy whole
breast plus 40 Gy to partial breast (reduced dose) or 40 Gy
partial breast only (partial breast). Primary endpoint was
ipsilateral local relapse rate (80% power to exclude a
+2.5% non-inferiority margin at 5 years for each test
group).
Findings: Between May 2007 and October 2010, 2018
women were recruited (control n=675, reduced dose:
n=674, partial breast: n=669). With a 72.2 month median
follow-up (IQR 61.7-83.2), 5-year local relapse rates were
1.1% (95%CI 0.5-2.3), 0.2% (0.02-1.2) and 0.5% (0.2-1.4) in
control, reduced dose and partial breast groups. Absolute
differences in local relapse rate compared with the
control group were -0.73% (-0.99, 0.22) for the reduced
dose and -0.38% (-0.84, 0.90) for the partial breast groups,
demonstrating non-inferiority for both test groups.
Photographs, patients and clinicians reported similar or
lower levels of adverse effects after reduced dose or
partial breast radiotherapy compared with whole breast
radiotherapy (see Table 1).
Interpretation: At 5 years, partial breast and reduced dose
radiotherapy showed local relapse rates non-inferior to
that observed following whole breast radiotherapy and