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compression of irradiation. Pain relief meant the
achievement of the score 3 down in the scale.
Results
The overall degree of response to radiotherapy was 51/62
(82.2%). The bone densities of both IMB and INMB dropped
by about 10 % from immediate to one month after
radiotherapy. The bone densities of IMB lesions increased
after then. There are close relations between the pain
control effects of radiotherapy and bone mineral density
change. Overall, from 3 months onward, the bone
densities of effective patients were significantly higher
than its pre-radiotherapy value.
Conclusion
Radiotherapy provide a meaningful supportive but not
perfect prolong benefit to many patients with bone
metastases. Mineralization effects of radiation therapy
depend on the characteristic metastases, especially the
effect of radiotherapy.
PV-0090 The risk of myelopathy after reirradiation of
the spinal cord.
M. Hiul Suppli
1
, P. Munck af Rosenchold
1
, H. Pappot
1
, S.A.
Engelholm
1
1
Rigshospitalet, Department of Oncology, Copenhagen,
Denmark
Purpose or Objective
Spinal re-irradiation has for a long time been considered
unacceptable due to the risk of radiation induced
myelopathy (RIM). Previous studies of of reirradation have
demonstrated the possibility of gait preservation with
minimal risk of RIM. Recommendations regarding
treatment dose, cumulative dose and time between
treatments to estimate the risk of RIM based on previously
reported data exist. However, these recommendations
have been based on retrospective analysis of smaller
cohorts of patients. Very limited data on the risk of
vertebral fractures (VF) is presently available for
fractionated palliative radiotherapy. In this study we
investigate the risk of RIM and VF in a large cohort of
consecutive patients treated multiple times with
palliative radiotherapy of the spine.
Material and Methods
From the year 2010 until 2014 a total of 2387 patients
received spinal irradiation with a palliative intent for
metastatic spinal cord compression. All patients were
reviewed for prior irradiation at either our facility or
another radiotherapy department. We find that 249
patients had potentially overlapping fields on the spinal
cord. After analysis of treatment plans, we find that 220
patients received re-irradiation of the spinal cord. Clinical
and treatment data was obtained from the patients’
records and RT planning system. Follow-up data was
obtained with approval from the Danish board of health.
Results
Patients had metastatic disease from breast, prostate,
lung, haematological or other cancers (22.7%, 21.8%,
21.4%, 3.2% and 30.9% respectively). Median time from 1st
irradiation until 2nd irradiation was 306 days, range 15
days-33 years. Median number of days from 2nd irradiation
until death was 91 days (range 1 days-5 years). Median
cumulative dose was 57.8 Gy (EQD2, with α/β=2)), range:
20.0-93.0Gy. Myelopathy or vertebral fracture likely
related to re-irradiation was observed in fifteen patients.
One patient developed myelopathy, for an additional five
patients, myelopathy could not be ruled out from
retrospective observations. Nine patients experienced a
vertebral fracture within the treatment field, which
resulted in neurological deficit for eight of these patients.
Conclusion
Patients suffering from spinal metastases and impending
spinal cord compression are often treated with radiation.
Patients with neurological deterioration due to metastatic
progression within a previously treated site of the spinal
cord face the risk of either fulminant metastatic spinal
cord compression or toxicity due to re-irradiation. Within
our cohort the incidence of myelopathy remained low, but
vertebral fractures were more prevalent. Patients with
spinal metastases treated with repeated radiotherapy and
potential long term survival should be considered for
spinal instrumentation.
PV-0091 Quantifying the Gap Between Radiotherapy
in the Elderly and the Demand for Age-Agnostic
Treatment.
T. Mee
1
, N.F. Kirkby
1
, K.J. Kirkby
1
, R. Jena
2
, A.
Choudhury
3
1
University of Manchester, Division of Molecular &
Clinical Cancer Sciences, Manchester, United Kingdom
2
University of Cambridge, Department of Oncology,
Cambridge, United Kingdom
3
The Christie NHS Foundation Trust, Clinical Oncology,
Manchester, United Kingdom
Purpose or Objective
Radiotherapy is prescribed less in the elderly compared to
other age cohorts. However, current research suggests
that there is little clinical evidence for this. In England,
the demand for radiotherapy services is greater than
capacity, so any increase in demand must be considered
carefully. This can be done using population-based
modelling systems. The potential effects of changing the
prescription paradigm in the elderly needs to be modelled
for a health care system at a local level to estimate the
impact on demand for services, due to variations in local
demographics and incidence rates.
Material and Methods
The Malthus model, an evidence-based tool for modelling
radiotherapy demand, was used to calculate the demand
for radiotherapy, broken down into age groups, for the
whole of England for 2015. The simulation was completed
in an age-agnostic manner. The simulation outputs were
compared to the Radiotherapy Data Set, a dataset of
delivered radiotherapy within the National Health Service