11 / 90
T
reatment
of
bone
and
soft
tissue
tumors
of
the
limbs
with
conformal
radiotherapy
and
intensity
-
modulated
radiotherapy
(IMRT)
R
ev
A
ssoc
M
ed
B
ras
2017; 63(6):477-480
479
of 31% in the maximum and average doses released in the
femur, in all patients.
10
(
C
)
Due to the dosimetric data published in the literature,
IMRT, when available, is the most recommended technique
for the treatment of soft tissue tumors in the limbs, while
conformal radiotherapy should be the least recommend-
ed technique.
2. I
s
there
less
toxicity
in
the
use
of
conformal
radiotherapy
or
IMRT
compared
to
conventional
radiotherapy
for
soft
tissue
tumors
in
the
limbs
?
Alektiar et al.
11
(
B
) analyzed the impact of IMRT on 41 adult
patients with end-stage sarcomas treated at the Memorial
Sloan-Kettering Cancer Center in New York between Feb-
ruary 2002 and May 2005. The risk of complications was
encouraging low, even including 25% of patients considered
to be at high risk for the development of bone fractures
after undergoing periosteal stripping or bone resection
during surgery. Only two patients (4.8%) developed grade
1 and 2 fractures and did not require surgical intervention
for repair. Other complications such as edema and joint
stiffness were also favorable when compared to conformal
radiotherapy. Folker et al.
12
(
B
), from the same institution,
analyzed 319 patients with end-stage sarcomas treated with
conservative limb surgery and adjuvant radiotherapy from
1996 to 2010. Of these, 154 were treated with conformal
radiotherapy and 165 with IMRT technique. Acute grade
≥ 2 radiodermatitis was more frequent in patients treated
with conformal radiotherapy (48.7% versus 31.5%; p=0.002).
Grade ≥ 2 chronic edema was also more frequent in patients
who received conformal radiotherapy (14.9% versus 7.9%;
p=0.05). There was no difference in the incidence of path-
ological fracture, neuritis and joint stiffness between the
two techniques. During the study period, no patient was
treated with conventional radiotherapy.
O’Sullivan et al.
13
(
B
) published the results of a phase
2 study involving 59 patients with end-stage sarcoma
treated preoperatively with IMRT. The incidence of surgi-
cal wound complications was 30.5%, less than the findings
of the National Cancer Institute Canada study, which was
43% with conventional radiotherapy.
Clinical results with IMRT are still short-term and
patients treated by different institutions require longer
follow-up to consolidate results, but it can be inferred that
these will not be inferior to those of conformal radiother-
apy. The use of a conformal technique should constitute
the minimum standard (least recommended) of radio-
therapy for bone and soft tissue tumors of the limbs.
3. I
s
there
a
difference
in
efficacy
between
conformal
or
IMRT
and
conventional
radiotherapy
?
There are no randomized studies comparing the three
planning and application techniques of radiotherapy. Due
to the rarity of the disease and the multiplicity of possible
presentations of limb tumors, it is unlikely that random-
ized trials for this evaluation will be performed.
In the American institution with the longest tradition
in treating limb tumors (Memorial Sloan Kettering Can-
cer Center), from 1996 to 2010, 395 soft tissue sarcoma
patients were treated with limb-preserving surgery and
radiotherapy.
12
(
B
) All patients after 2002 were treated
with IMRT. Their study is the largest existing and com-
pares the conformal and IMRT techniques. Convention-
al radiotherapy was not used in this period. In the study,
the first 154 patients received adjuvant conformal radio-
therapy and the following 165 received IMRT. Analysis
of patient and tumor characteristics showed that the
IMRT group had significantly more risk factors for recur-
rence (greater percentage of surgeries with positive or low
margins and higher percentage of high-grade tumors).
Patients treated with IMRT had fewer local recurrences
(8% versus 15%, p=0.05). In a detailed multivariate analy-
sis, IMRT remained a protective factor of independent
recurrence (HR=0.458; CI 0.235-0.891).
A Canadian study compared a group of patients
treated with IMRT in a phase 2 protocol with another
group previously treated with conformal radiotherapy in
a randomized study from the same institution.
14
(
B
) The
analysis showed 5-year recurrence-free survival of 88% in
the IMRT-treated group and 89% of the historical control
with conformal radiotherapy.
A study in children with rhabdomyosarcoma treated
in a prospective protocol from the American Children’s
Oncology Group showed improvement in target volume
coverage with IMRT. However, this did not translate into
improvement of disease control results compared to con-
formal radiotherapy.
14
(
C
)
There is therefore no evidence of good quality that
demonstrates greater efficacy between IMRT and conform-
ing techniques, making it impossible at this moment to
recommend one over another. Regarding conventional
radiotherapy, despite the absence of evidence of good
quality, we recommend whenever possible that this tech-
nique not be used, due to its inability to allow evaluation
of risk structures. In addition, there is a great risk of geo-
graphic error of the target to be irradiated due to the
complex tissue irradiation needs in limb tumors.