Commentary
How Effective is Intensity-Modulated Radiation Therapy When Treating Patients with Emergency Metastatic Spinal Cord Compression?
Jun-Ho Lee1 and Seok Ho Lee2*
1Department of Emergency Medical Technology, Daejeon University, South Korea
2Department of Radiation Oncology, Gachon University of Medicine and Science, South Korea
*Corresponding author: Seok Ho Lee, Department of Radiation Oncology, Gachon University of Medicine and Science, Incheon, South Korea
Published: 18 Jul, 2018
Cite this article as: Lee J-H, Lee SH. How Effective is
Intensity-Modulated Radiation Therapy
When Treating Patients with Emergency
Metastatic Spinal Cord Compression?.
Clin Oncol. 2018; 3: 1495.
Commentary
Bone metastasis is one of the most common metastatic lesions in cancer patients. Spinal
metastasis, in particular, is a more noticeable form of bone metastasis due to the symptoms and
urgency of treatment. Spinal metastasis may cause neurological damage in addition to pain, which
can lead to a dramatic deterioration of patient's quality of life owing to sensory changes, loss or lack
of strength and rectal capacity with intestinal obstruction. It is a representative malady requiring an
emergency treatment [1].
Spinal cord compression syndrome is a manifestation of the symptoms requiring such an
emergency treatment caused by spinal metastasis. It is a symptom caused by the compression of
spinal cord especially that of the epidural spinal cord with a tumor from bone metastasis. The most
common causes of spinal cord compression syndrome due to bone metastasis are lung cancer
and breast cancer. The most common involvement site is the thoracic region; the most common
symptom is pain [2].
Steroids should be given first as a treatment upon diagnosis and surgery and/or radiotherapy
should be performed depending on the extent of the compression of the spinal cord [3]. It is
important to diagnose spinal cord compression syndrome early during the pain phase and to
treat it early because the symptomatic pain may be accompanied by lower leg strength or sensory
abnormality. It is of primary importance for patients and caregivers to be aware of pain, which is
the initial indication of spinal cord compression syndrome, and to promptly notify the primary care
physician when symptoms develop [4].
It is important to carefully observe changes in neurological symptoms in patients with bone
metastasis, especially in patients with spinal metastasis. Immediate examination and appropriate
treatment should be performed when symptoms are present. If radiotherapy is needed, based on the
overall prognosis of the patient and extent of the disease, it is important to determine which type of
radiation treatment to be used.
Recently, there have been attempts to use Stereotactic Body Radio Therapy (SBRT), using the
Intensity-Modulated Radio Therapy (IMRT) and image-guided radiation therapy, to treat spinal
cord compression syndrome (Figure 1). It is known that radiation therapy can also be repeated
using IMRT techniques when the tolerance dose of the spinal cord is limited [5]. In particular,
stability and efficacy have been reported not only in retreatment but also in primary care [6]. One
year after treatment, the local control rate is reported to be approximately 80% to 85% [7,8].
Although various radiotherapy techniques have been developed in patients with spinal cord
metastasis with or without spinal cord compression syndrome, it is very important to determine the
appropriate radiation therapy technique while considering the extent of disease progression and the
patient’s survival. In IMRT, the time from treatment planning to the start of radiation therapy may
be several days longer compared with conventional two- or three-dimensional radiation therapy
techniques. Therefore, in all patients with spinal metastases, IMRT should not be performed. In the
case of SBRT in particular, both treatment plans and quality verification process to be essentially
included. Because of this, initiation of a treatment delayed in even one or two days may adversely
affect the prognosis of the quality of life for the patient. In the case of spinal cord compression
syndrome, radiotherapy is to be needed as quickly as possible.
Actual treatment planning time alone may not be significantly
different from that of three-dimensional conformal radiotherapy
[9]. However, in order to perform SBRT for spinal cord compression
using the IMRT technique, consideration must be given to additional
radiologic imaging such as spine MRI to facilitate accurate contouring
for target and normal cells in tissues such as the spinal cord, as well as
to take into account the time for contouring, treatment planning, and
quality assurance. In such cases, the difference in time will be longer.
Even when using the latest RT technique, if the appropriate
patient selection is not achieved, the cost and hospital stay period
for the patient may be increased without improving the treatment
efficiency.
The use of IMRT, which has excellent efficacy in protecting
normal tissues, especially in those of the spinal cord during treatment,
also enhances the probability of tumor control; an improved
treatment response including complete remission that could not have
been expected from conventional three-dimensional radiotherapy
can be attained. However, compared to three-dimensional or twodimensional
radiotherapy, IMRT takes a relatively longer time from
the beginning of treatment planning to the start of treatment. It is
unsatisfactory that it becomes a determining factor for the use of such
an important treatment method. The length of time from the treatment
plan to the start of treatment is considered to be an important factor
in the determination of the treatment method because the time to the
start of treatment is important in determining the quality of life of
patients with spinal cord compression syndrome. From that point of
view, the choice of IMRT may have a disadvantage.
There is a question as to whether surgery or SBRT should
be performed first for the patient with spinal cord compression
syndrome. According to Samuel et al. [10], in the case of grade IV or V
epidural compression, urgent treatment for spinal cord compression
is especially important and surgery should be considered. If surgery is
not possible, radiotherapy is needed. It may be better to perform twoor
three-dimensional radiotherapy than to perform SBRT using an
IMRT. It is also reported that if patients are not selected carefully, the
risk of disease relapse, especially the occurrence of epidural disease,
myelopathy and vertebral compression fracture, increases [11].
Considering this, more sophisticated indications for IMRT for spinal
cord compression are needed, and we hope to see this issue resolved
in the future. We also expect to improve radiotherapy techniques,
including the IMRT. This would maintain the existing treatment
effect while reducing the treatment planning time compared to the
existing two-dimensional or three-dimensional radiation treatment
techniques.
Figure 1
Figure 1
Stereotactic Body Radio Therapy (SBRT) based on Intensity-Modulated Radiation Therapy (IMRT) planning for spine metastasis.
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