METHODS
We retrospectively investigated patients with brain metastasis who were treated at the Cumhuriyet University
center for radiation oncology between 2006 and 2014.
RESULTS
The data of 277 patients were analyzed. Age of the patient, performance status, length of time to metastasis,
site of primary disease, and performance of metastasectomy were determined to be factors that affect
prognosis. Independent prognostic factors were found to be: time to metastasis (hazard ratio [HR]: 0.72;
95% confidence interval [CI]: 0.52-0.99; p=0.0047), performance status (HR: 1.40; 95% CI: 1.07-1.85;
p=0.015), and metastasectomy (HR: 0.54; 95% CI: 0.33-0.89; p=0.017).
CONCLUSION
Survival rate was better in patients with breast cancer, longer time before metastasis, good performance,
and those who had undergone metastasectomy. Therapeutic approaches should be planned with consideration
that patients exhibiting these characteristics might have more favorable therapeutic outcomes.
Keywords: Brain metastasis; metastasectomy; prognostic factors
Although current advances in visualization techniques
have, in parallel, led to earlier diagnoses and
better local treatments of cancer, patient survival is still
an important problem. However, the quality of life and
survival of the patients have improved, to some extent,
with improvements in oncological treatments.[
In this study, we investigated the clinical and demographic
prognostic factors that affect the survival of
cancer patients with brain metastasis. In addition, we
aimed to identify any possible independent predictors
related to overall survival.
The statistical analysis was performed using the SPSS statistical software (version 15.0), and the rate of survival was calculated using the Kaplan-Meier analysis. The duration of overall survival covered the time from the date of the diagnosis of brain metastasis until death or the date of the last control. Moreover, a multivariate analysis (Cox Regression Analysis) was performed to evaluate the independent factors that affect survival. Those variables found to be significant in the univariate analysis were evaluated using the multivariate analysis, and a p value of less than 0.05 was considered to be statistically significant. Consent from the Cumhuriyet University School of Medicine Ethical Committee was received prior to the study, with regard to collecting, evaluating, analyzing, and interpreting the data.
The primary diagnoses of the patients were: 162 cases of lung cancer (58%), 57 cases of breast cancer (21%), 17 cases of gastrointestinal system cancer (6%), 14 cancer patients with unidentified primary sites (5%), 12 cases of genitourinary system cancer (4%), 8 cases of gynecological cancer (3%), and 7 cases of other types of cancer (3%).
All of the patients had undergone total cranial irradiation, in which three-dimensional conformal radiotherapy was applied using a Varian DHX Eclipse planning system. The radiotherapy was applied at a dose of 3000 cGy, with 300 cGy/day for the total cranial area. Other treatments were also applied for the brain metastasis, with 30 patients (11%) having undergone metastasectomies. A second series of irradiation was required in 21 patients (8%), due to progression, and cranial conformal radiotherapy was applied as the second serial irradiation. This protocol was conducted at a total of 2000 cGy, with 200 cGy/day for the cranial area. Stereotactic radiosurgery (SRS) was not applied in any of the patients.
Overall, the median survival was determined to be 3 months (1–98 months), the mean duration of survival was 7.6±0.68 months, and the median value of the time to metastasis was 11 months (1–119 months).
Based on the univariate analysis, the prognostic
factors which affected survival included the site of the
primary disease (breast cancer, p=0.035), age of the patient
(<50 years old vs ≥50 years old, p=0.033), performance
status of the patient (p=0.005), history of metastasectomy
(p=0.006), and time for the development
of metastasis (p=0.055). However, the gender, comorbidity,
metastasis at diagnosis, and second series of radiotherapy
(RT) were not determined to affect survival
(p>0.05). Table
Those independent prognostic factors which positively
affect survival were found to be: a favorable ECOG performance status (HR=1.40, 95% CI=1.07–
1.85; p=0.015), the application of metastasectomy
(HR=0.54, 95% CI=0.33–0.89; p=0.017), and time to
metastasis of greater than 18 months (HR=0.72, 95%
CI=0.52–0.99; p=0.047). The independent prognostic
factors, as determined via the multivariate analysis, are
illustrated in Table
Certain important prognostic factors can be used
to assess the therapeutic approach towards patients
with brain metastasis. In three studies conducted by
the Radiation Therapy Oncology Group (RTOG), a
total of 1.200 patients were analyzed to determine the
prognostic factors in brain metastasis, by evaluating
whole brain radiotherapy with different fraction-dose
schedules. In this analysis, the age, performance status,
control of the primary tumor, and presence or absence
of extracranial metastasis were determined to be important
prognostic factors. As a result of the analysis, three prognostic classes were determined and defined
as the recursive partitioning analysis (RPA), including
RPA classes I, II, and III:[
1. Class I: patients younger than 65 years old with
brain metastasis only, and with the lower Karnofsky
Performance Status (KPS) of 70.
2. Class II: those patients not included in RPA classes
I and III.
3. Class III: patients with a KPS of less than 70.
The best survival was found in RPA class I, with a
median value of 7.1 months, while the worst was in RPA class III, with a median value of 2.3 months. The
median value of survival was 4.2 months in RPA class
II.[
The Eastern Cooperative Oncology Group (ECOG)
performance status is used widely in oncology to assess
a patient’s state of performance. This performance
status has been reported in the literature as an efficient
and preferable prognostic factor for metastatic tumors.
[
Some studies have reported that the site of the primary
tumor is another important prognostic factor
that affects overall survival.[
Additional studies in the literature have reported
that the time from the initial diagnosis to brain metastasis
is closely related with the prognosis.[
Metastasectomy is another factor which determines
a patient’s prognosis, and the duration of survival has
been reported to be quite long in those patients that
underwent metastasectomies.[
The application of whole brain irradiation following
surgical intervention is still a matter of debate; however,
all of our patients underwent cranial radiotherapy
following surgery, so we could not make an interpretation
of this issue. In the study by Duransoy et al., the
duration of survival was 13 months in those patients
undergoing post-operative RT, but it was 5 months in
those patients who did not undergo post-operative RT
(p<0.001). Therefore, we believe that the application of
cranial radiotherapy following surgery is a better approach.
Limitations
This research had some important limitations; for
example, it was a retrospective study with a limited
amount of data for analysis. Therefore, these findings
should be confirmed with prospective controlled randomized
trials. The second limitation was related to
sample size, since our data was based on a relatively
small study population and involved records from a
single center. Larger cohort studies would be beneficial
in obtaining stronger statistical results. Finally, this
research did not include any patients who underwent
stereotaxic RT. Therefore, we suggest that further studies
which include cases of the same primary disease
(e.g. breast cancer), and that also include a sufficient
number of cases undergoing metastasectomy and stereotaxic
RT would make important contributions to
the literature.
Disclosure Statement
The authors declare no conflicts of interest.