Page 65 - Read Online

Page 10 of 16 Enrique et al. J Cancer Metastasis Treat 2019;5:54 I http://dx.doi.org/10.20517/2394-4722.2019.20

Figure 5. Whole-brain radiation therapy treatment plan using a 3D conformal technique with two opposite lateral fields

One of the first aleatorized studies employed SRS as a boost in patients with one to three brain metastases
that had previously received treatment with WBRT, showing an improvement in functional status in all
patients and an improvement in overall survival in patients with a single metastasis [52,57] .

The retrospective series published by Wang et al. in 2015 analyzed patients with brain metastases,
[58]
comparing GammaKnife SRS alone, GammaKnife SRS with WBRT, surgery and SRS (as an adjuvant
treatment to the surgical cavity), and a triple modality (surgery, SRS, and WBRT). For patients with a single
metastasis and those with multiple lesions, the triple modality treatment was found to have greater positive
effects on median survival than GammaKnife SRS alone. That study was not a prospective trial, and it also
found better results for bimodal treatment than for GammaKnife surgery alone (as opposed to previous
clinical trials). The authors concluded that WBRT is a good alternative as a rescue treatment for patients who
had previously received SRS [58,59] .

SRS has broadened the terrain of the primary treatment of brain metastasis, especially in patients with
good functional status and in those who have one to three metastases at diagnosis with limited extracranial
disease [As shown in Figures 6 and 7]. Therefore, it is important to note that better global control of
[58]
metastasis can be obtained with WBRT and SRS, which have an impact on local control and overall
survival . Patients whose disease is more limited in extent (up to four metastases for SRS protocols) may be
[51]
treated with WBRT and SRS or SRS alone without improvement in their overall quality of life. A worsening
of cognitive performance is found in patients treated with WBRT plus SRS, which affects their quality of life
and ultimately their overall survival. These results were found by the trials conducted by Brown et al. and
[60]
Chang et al. . ASTRO and NCCN guidelines agree in recommending management with SRS in patients
[61]
with a limited number of brain metastases.

The utility of SRS for patients with five or more brain metastases is unclear. The only prospective study
that has evaluated patients with these characteristics was conducted by Yamamoto et al. , who assessed
[62]
208 patients with 5 to 10 metastases, 531 patients with 2 to 4 metastases, and 455 patients with a single
metastasis, with a maximum lesion diameter of 3 cm. The most important result was that the number
of brain metastases did not affect overall survival, while the volume of intracranial tumors ranged from
0.02 to 13.9 cc, and the average survival for patients with 5 to 10 metastases was 10.8 months. Deaths from
neurological causes did not exceed 10% and there were no significant differences among groups. Finally, it
was concluded that the progression of systemic disease was the main cause of death, the initial number of