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G
uidelines
for
the
treatment
of
central
nervous
system
metastases
using
radiosurgery
R
ev
A
ssoc
M
ed
B
ras
2017; 63(7):559-563
561
Recommendation
Radiosurgery should preferably be performed in patients
with up to four lesions and a maximum diameter of 4 cm.
3. W
hat
are
the
advantages
of
radiosurgery
compared
to whole
brain
radiotherapy
?
Radiosurgery has the advantage of offering a more con-
formed and localized treatment, with larger ablative
doses than whole brain radiotherapy.
29-32
Thus, it minimizes the deleterious effects of whole
brain radiotherapy with regard mainly to neurocognitive
deficit and declining quality of life.
22,30,32-34
(
A
)
Another important point is that radiosurgery offers
higher rates of local control, even in patients with histo-
logically radioresistant tumors (requiring higher doses of
ionizing radiation, e.g., melanoma, renal tumors, and sar-
coma) compared with whole brain radiotherapy.
35,36
(
B
)
Recommendation
Radiosurgery decreases the risk of neurocognitive decline
and can positively impact the patients’ quality of life.
4. W
hat
is
the
effectiveness
of
radiosurgery
in
the
approach
of
patients
with
brain
metastases
?
Radiosurgery alone for the treatment of brain metasta-
ses produces local control rates ranging from 65 to
94%.
15,37,38
(
B
)
The main factors related to local control after radio-
surgery are: characteristics of tumor lesion and treatment
dose. Doses lower than 14 Gy and cystic and necrotic
lesions are associated with a greater likelihood of recur-
rence.
39,40
(
B
)
The efficacy of radiosurgery does not depend on the
histological type of the primary tumor since local control
rates are similar in both radiosensitive and radioresistant
tumors.
41-43
(
B
)
Recommendation
Radiosurgery is effective for the treatment of patients
with brain metastases, even in those with histologically
radioresistant primary tumors.
5. W
hat
are
the
benefits
and
disadvantages
of
performing
two
treatment
modalities
involving
radiosurgery
and
whole
brain
radiotherapy
in patients with brain metastases
?
There have been some randomized phase 3 trials evaluat-
ing the use of radiosurgery (RS) associated with whole
brain radiotherapy (WBRT) or WBRT alone in patients
with brain metastases and limited disease (1 to 4 intra-
parenchymal lesions).
20,21
Aoyama et al. reported a 12-month CNS recurrence rate
of 46.8% for the WBRT+RS group and 76.4% for RS alone
(p<0.001), and 73 and 89% (p=0.002) of local control for
the RS and WBRT+RS groups, respectively. However, there
was no difference in overall survival between groups.
29
(
A
)
Chang et al. reported that patients treated with
WBRT+RS have a rate of learning decline and mean func-
tional memory of 52 versus 24% in the RS group. Although
brain metastasis-free survival rates at one year were higher
in the WBRT+RS (73%) than in the RS (23%) group, there
was no difference in overall survival and RS patients were
easily rescued with new therapy.
30
(
A
)
Brown et al. presented data according to which the
addition of WBRT to RS, despite improving local control
(50.5 x 84.9% at one year with RS alone and WBRT+RS,
respectively), did not lead to an increase in overall sur-
vival and was negatively correlated with some cognitive
decline, especially for memory, verbal fluency and im-
mediate memory in the WBRT+RS group (p<0.05).
44
(
A
)
In a systematic review that included the meta-analysis
of individual data from randomized clinical trials, the
authors noted that in patients aged less than 50 years, with
1 to 4 lesions and good performance, the use of RS alone
led to longer overall survival, whereas the initial omission
of WBRT did not produce any more failures in CNS.
45
(
A
)
In addition, despite worse local control rates and higher
rates of salvage treatment, RS proved in the economic
analysis to be more cost effective than WBRT+RS.
46
(
B
)
Recommendation
The addition of whole brain radiotherapy in patients
treated with radiosurgery allows greater intracranial local
control, despite no positive impact on overall survival.
The use of whole brain radiotherapy may be related to
worsening of cognition, verbal function and memory.
6. A
fter
surgical
resection
of
brain
metastases
,
is
there
a
role
for
adjuvant
radiosurgery
in
the
surgical
bed
?
In the postsurgical adjuvant scenario, one of the standard
treatment regimens is toperformwhole brain radiotherapy.
47-48
However, in order to avoid the detrimental effects of
whole brain radiotherapy, some authors advocate the use
of adjuvant radiosurgery in the surgical bed.
A phase 2 clinical study evaluated the use of radio-
surgery with a median dose of 18 Gy in patients with
performance status ≥ 70 and ≤ 2 resected brain metas-
tases. Local and regional failure rates of 22 and 44%,