S250
ESTRO 36
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The role of radiotherapy in pancreatic ductal
adenocarcinoma (PDAC) remains controversial. In contrast
to the notion that all patients with PDAC die of metastatic
disease, at least a 20% suffer and die from local
recurrence. The latter provides a strong rationale for
improving local control using radiotherapy, including dose
escalation with SBRT. The advent of modern RT and
imaging technology can reduce toxicity without
compromising efficacy. International consensus on the
definition of R1-resection in primarily and borderline
resectable PDAC is needed to better define radiotherapy
indications. SBRT and chemoradiotherapy (CRT) have to
be tested in the context of more efficient chemotherapy
regimens, such as FOLFIRINOX and Gemcitabine/Nab-
paclitaxel if it is to unmask the importance of improved
local control. The development of molecular signatures to
differentiate patients with high risk of developing only
local recurrence from those likely to die of distant
metastases is urgently needed. Preclinical and
patient
data
indicate
testing
the
efficacy
of immunotherapeutics in combination with (C)RT in
future clinical trials.
SP-0471 Standard treatment in anal cancer: where do
we stand and where should we go?
R. Muirhead
1
1
CRUK/MRC Oxford Institute for Radiation Oncology,
Oncology, Oxford, United Kingdom
Introduction - Anal cancer is a rare disease but the
incidence is increasing rapidly. Despite its rarity there is
significant research, development and interest in this
topic with large phase III trials involving hundreds of
patients’ completed, and literature on anal
cancer regularly on the “most read” list of radiotherapy
journals. The initial phase III trials investigated the use of
concurrent chemotherapy with radiotherapy, confirming
the benefit of concurrent chemoradiotherapy using
Mitomycin and Fluorouracil. These trials changed the
standard treatment in anal cancer from APR with
permanent stoma to CRT. Subsequent phase III trials have
investigated diverse concurrent chemotherapy regimens
and the different settings of systemic therapy; namely the
role of neo-adjuvant and adjuvant chemotherapy and
different concurrent regimens. However these strategies
failed to demonstrate significant impact on outcome, and
the optimal concurrent regimen remains Mitomycin and
Fluorouracil. The ESMO-ESSO-ESTRO and NCCN guidelines
support the use of capecitabine as an alternative to
fluorouracil, however phase III evidence supporting this
recommendation is not available. The phase I and II
studies, multicentre and single centre data supporting this
regimen, highlight the different toxicity profiles. Due to a
failure to demonstrate improved outcomes in recent phase
III trials investigating different systemic strategies,
moving forward we will need to consider how improving
the radiotherapy component of our treatment can improve
both cancer outcomes and the late toxicity of this toxic
but effective treatment.
Radiotherapy Technique - The RTOG 0529, a phase II study
investigating the acute toxicity of IMRT in comparison to
the historical RTOG 9811, raised some important questions
regarding the challenges of implementation of IMRT in
anal cancer. The central review of volumes revealed a
large numbers of revisions required in contouring. In
addition there is a correlation between plans that fail to
meet the recommended dose constraints and G3 toxicity.
In implementing IMRT, thought has to be given to volumes
to be included, doses and fractionations, margins used and
organ at risk constraints; each of these issues alongside
the relevant literature will be discussed in the context of
designing the UK IMRT guidance.
Late toxicity and Quality of Life – Until recently there was
minimal literature on the late toxicity of this treatment
despite cure rates of >70%. With the requirement to
quantify late toxicity in order to design studies to improve
morbidity and increasing awareness of cancer
survivorship; there is renewed interest in this topic. A
number of recent series have reported the late toxicity
following IMRT using a combination of physician recorded
and patient reported outcome measures. While there is
recovery of the majority of acute side effects and quality
of life 3 months after completing treatment, diarrhoea,
urinary incontinence and dyspareunia persisted beyond 1
year. These adverse effects were reported following
"modern" CRT techniques therefore it is arguable that to
see an improvement in these outcomes, we will need to
explore individualising treatment dose to minimise late
effects.
RT stratification according to stage – Although there has
always been much interest in increasing doses with
external beam or brachytherapy boosts in all stages of anal
cancer until recently there was no dose response data
available. The RTOG 0529 study set a precedence for
stratifying dose delivered according to tumour stage. This
lecture will discuss the dose response model which reports
while there was a dose response in both early and locally
advanced stages of tumour, the improved local control
rates achieved by dose escalating in locally advanced
tumours far exceeds what can be achieved by dose
escalating in early tumours.
Future international trials - The UK led PLATO study trial
(ISRCTN88455282) is funded by Cancer Research UK and
incorporates many of the themes of the teaching lecture.
PLATO is a unique “umbrella” trial addressing a number of
radiotherapy questions in the loco-regional management
of anal cancer. It incorporates 3 individual trials: ACT3 -
for T1N0 anal margin tumours, evaluating a strategy of
selective reduced dose chemoradiotherapy after local
excision, within a single arm phase II trial; ACT4 – for T1-
2 N0 (≤4cm) tumours, evaluating reduced dose
chemoradiotherapy to the primary tumour, in a
randomised 2:1 phase II study, with the aim of reducing
toxicity and maintaining efficacy; ACT5 – for T2 N1-3, T3/4
Nany, evaluating dose escalation within a seamless
randomised trial design moving from pilot to phase II to
phase III, with the aim of reducing locoregional failure.
The primary endpoint for all 3 trials is 3 year local regional
failure, key secondary outcomes will focus on patient
reported outcome measures.
Joint Symposium: ESTRO-RANZCR: Big data to better
radiotherapy
SP-0472 The pros, cons, process and challenges for
achieving better radiotherapy through data -an
introduction
L.C. Holloway
1,2,3,4
1
Ingham Institute and Liverpool and Macarthur Cancer
Therapy Centres, Medical Physics, Sydney, Australia
2
University of Wollongong, Centre for Medical Radiation
Physics, Wollongong, Australia
3
University of Sydney, Institute of Medical Physics,
Sydney, Australia
4
University of New South Wales, South West Sydney
Clinical School, Sydney, Australia
The magnitude and use of data is expanding in many areas
including medicine. The opportunities for using data to
improve our knowledge and understanding are many and
varied including demographic, disease and outcome
investigations. Within current radiotherapy practice data
may be collected in a very rigorous approach within for
instance a clinical trial framework and data is also
collected in an ongoing fashion during standard clinical
practice. It is possible for us to gain knowledge from both
rigorously collected data and clinical practice data.
The gold standard of randomised clinical trial (RCT)