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fluorescence guidance have not studied the tumor genes and in control. It is clear that the group analysis was not
[2]
the good results could be genetically related. Further studies homogeneous and it might be due to a lack of protocols and
are needed to direct correlate the genetically aggressive a standardized approach to all lesions. Furthermore, there is
tumors and the use of 5-ALA. need for standardization of reports for a systematic-review
analysis and for future trends. Even though, the theorical
Another substance used for guidance is the sodium benefits of the novel techniques should impulse more
fluorescence, which accumulates in high neovascularization randomized, controlled trials with better baselines.
areas, also seen in high-grade lesions. Recent studies point
to an increase of EOR and GTR, but without increasing of Future technologies
the overall survival rate. After review, 5-ALA had 91% Neuronavigation has become more popular and the
[64]
sensitivity, 59% specificity, 85% PPV, and 71% negative localization of tumors has come to practice with the
predictive value for histopathological identification of navigation instrument and the monitor. Even though, what
malignant glioma. Future objectives in fluorescence if we had the images seen in the surgical field continuously,
[65]
guidance may lead to better microscopic visualization without navigators? The augmented reality has come to
methods for the fluorescein such as filters, special masks time with the objective of sending information to surgical
or lens. [66] field without monitors.

Current evidences Augmented reality technique has four steps: virtual image
The Cochrane group has reviewed all the reports of creation; real environment; projection and registration.
image-guided surgery for brain tumor resection and Thus, image can be seen in the surgical field and the virtual
found some issues. Most of the studies are not controlled interface can be used. The augmented reality is important
and randomized; also patients’ baselines and tumor in planning surgery and having the lesion visible in the skin
aspects were heterogeneous in most of the groups and the since the beginning of the surgery. The augmented reality
resecability of them was different between intervention can be applied not only to the surgical field to prepare a
and control groups. Despite limitations and low quality better surgical incision and approach, but also to the
[2]
of evidence, the analyses from the classical reports from surgical view in the microscope, which is important when
Senft 2011, Stummer 2006 and Wu 2007 showed a trend the surgeon cannot take his or her eyes/instruments from
for better results. Complete tumor resection was achieved the microscopic field. [67,68]
[2]
with iMRI in 23/24 (96%) of participants in the intervention
arm group compared with 17/25 (68%) of participants in Moreover, the augmented reality could also include other
the control arm (relative risk [RR] for incomplete resection parameters such as fiber tracts or important structures that
0.13, 95% confidence interval [CI]: 0.02-0.96, low quality should not be approached. As an innovation in neurosurgical
evidence). [2] surgery, there are few studies but promising applications. [67]

Using 5-ALA, complete resection was performed in 90/139 Also other interesting concept is the regional vs. global
(65%) of the intervention arm vs. 47/131 (36%) of the DTI biomarkers for glioblastoma. Most of this lesions are
control arm (RR for incomplete resection 0.55, 95% CI: heterogeneous with multiple histological features and can
0.42-0.71, low quality evidence). Finally, neuronavigation lead to different degrees of malignancy, thus biopsies can be
with DTI was achieved among the 85 participants with different in multiple areas. DTI is routinely used to locate
high-grade glioma and complete tumour resections were high-grade areas, but the development of a sensitive and
achieved in 32/42 in the DTI arm vs. 14/43 in the control specific biomarker, remains an issue. Also, the role of DTI-
arm (RR for incomplete resection 0.35, 95% CI: 0.20-0.63, derived tensor metrics in normal brain and infiltrated brain
very low quality evidence). Among 129 participants with is important for the distinction of tumor infiltration in non-
LGG, complete tumor resections were achieved in 40/61 contrast-enhanced areas. As the GBM been considered as a
in the DTI arm vs. 42/68 in the control arm (no significant whole brain disease, DTI analysis of the whole brain might
difference). In survival analysis, the 5-ALA groups had be more interesting than studying just the lesion areas.
[2]
a median survival of 15.2 months (95% CI: 12.9-17.5) in Roldán-Valadéz et al. showed that relative anisotropy, axial
intervention group and control with 13.5 months (95% diffusivity (AD), Cl (linear tensor), Cs (spherical tensor),
CI: 12.0-14.7). The neuronavigation-DTI arm was 21.2 were important for regional DTI tumor analysis. Also,
[69]
months (95% CI: 14.1-28.3) vs. 14.0 months (95% CI: 10.2- Cortez-Conradis pointed for AD, Cl, Cs and introduced the
17.8). Only in World Health Organization grade IV tumors whole brain concept. The advantages of whole brain DTI
analysis, neuronavigation-DTI arm was 19.3 months (95% analysis are: Decrease of bias associated with the analysis
CI: 15.2-23.5) vs. 11.1 months (95% CI: 7.3-15.2) in the of just one region of interest; the tumor and edema regions
control arm. In time to progression, the median time in are included; lesions not perceived by the radiologist’s eye
[2]
iMRI group was 226 days (95% CI: 0.0-454) vs. 154 days on conventional sequences would be included in a global
(95% CI: 60-248) in control. With 5-ALA, it was 5.1 assessment; it may avoid problems associated with partial
months (95% CI: 3.4-6.0) vs. 3.6 months (3.2-4.4 months) volume effects, and inaccurate image coregistrations.
[70]
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Journal of Cancer Metastasis and Treatment ¦ Volume 2 ¦ March 11, 2016 ¦