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C
astilho
MS
et
al
.
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ev
A
ssoc
M
ed
B
ras
2017; 63(6):477-480
crovasculature caused by irradiation. These sequelae may
lead to limitation of limb functions, such as articulation
and movement, and consequent impairment of quality
of life. In some situations, sequelae may leave the patients
disabled and, depending on their profession, drive them
out of the job market.
Therefore, the radiation dose should be directed as
concentrated as possible to the area at risk of local recur-
rence after surgery or in the primary tumor prior to surgery,
also minimizing or avoiding the therapy in areas at risk
that do not need to be treated, such as those with soft tis-
sues, bones, tendons, vessels, nerves, muscles and joints.
In recent years, the technical development of radio-
therapy has allowed the planning of the radiation deposit
to be made using imaging tests, which is not performed
with conventional radiotherapy, but with conforming tech-
niques and IMRT.
Conventional radiotherapy is performed from simple
radiographs of the affected limb, on which the area to be
irradiated is drawn in two dimensions. Dose calculation
is done manually taking into account the size of the field
and the thickness of the limb. This technique can not
estimate the amount of dose released in areas that do not
require treatment. Because of these characteristics, con-
ventional radiotherapy has been abandoned for several
years in developed countries and is not recommended by
the Brazilian Society of Radiotherapy for the treatment
of limb tumors.
1
(
D
)
Conformal radiotherapy was developed so that the
planning would be performed with imaging tests such
as computed tomography, and the calculation of the
dose with computerized systems that evidence the dose
distribution in three dimensions. With this, it is possible
to estimate if the dose distribution is adequate and safe.
The planning system allows various combinations of
radiation input fields to be modified in their incidence
and size, in order to focus the radiation only where it is
needed. Thus, radiotherapy has become potentially saf-
er and more effective for patients with bone and soft
tissue tumors of the limbs.
IMRT radiotherapy was developed from conformal
radiotherapy with the addition of a planning system that
can place radiation filters in the front of the beam so that
the homogeneity of dose is greater, avoiding excessive
doses and bypassing risk structures more efficiently.
Based on these premises, this guideline aims to show
the benefits of the most modern techniques of radio-
therapy in the management of patients with bone and
soft tissue tumors of the limbs, with the support of pub-
lished dosimetric and clinical evidence.
To that end, three questions were elaborated to answer
the main points.
1. I
s
there
a
dosimetric
superiority
in
the
irradiation
of
soft
tissue
areas
with
conformal
radiotherapy
or
intensity
-‑
modulated
radiation
beam
(IMRT)
compared
to
conventional
radiotherapy
?
Although limb neoplasms are rare diseases, which makes
it difficult to conduct prospective and randomized stud-
ies for a dosimetric comparison between radiotherapy
techniques, there are some experimental or observational
studies of better consistency showing that both IMRT and
conformal radiotherapy are superior to radiotherapy as
they allow the evaluation of irradiated treatment volumes
and doses in normal structures of interest such as bones,
surgical wound, graft flaps and skin bands, in both adults
and children with indication of pre- or postoperative
radiotherapy. Six studies have shown that the dose of
radiation in areas of risk is greatly reduced when IMRT
or conformal technique are used compared to conven-
tional radiotherapy.
2-7
(
C
)
Three more recent studies have demonstrated supe-
riority of the IMRT technique compared to conformal
radiotherapy. All of them found greater conformity and
dose homogeneity in treatment volumes and dose reduc-
tion for risk structures.
8-10
(
C
)
Robinson et al. compared the dosimetric plans of 11
patients with endometrial tumors between conventional
radiotherapy and conformal radiotherapy. The volume
of treatment with conformal radiotherapy was reduced
in all patients. Normal muscle volume was reduced by
30% in thigh tumors. Likewise, the volumes of femur,
tibia/fibula and ileum were reduced by 38%, 18% and
14%.
2
(
C
) Stewart et al. updated these results by analyzing
ten patients submitted to adjuvant radiotherapy after
limb-preserving surgical resection due to thigh sarcomas,
comparing conformal radiotherapy and IMRT. For all
patients, the IMRT plans showed better conformity than
those of conformal radiotherapy. IMRT allowed the
release of a lower dose in the femur and normal tissue.
In patients with lesions extending into the pelvis, blad-
der, rectum and bowel doses were also minimized. For
the other parameters, there was no difference between
techniques.
6
(
C
)
Sladowska et al. also presented the comparative results
between IMRT and conformal radiotherapy in ten patients
with thigh sarcomas. IMRT demonstrated better dose
conformity in the target volume, especially when concave
dose distribution was required. It also promoted a decrease