ICPFS Evaluated by Two Blinded and Independent Radio-oncologist With MRI Clinical Trial
Official title:
Nitroglycerin Plus Whole Intracranial Radiotherapy for Brain Metastases in Non-small Cell Lung Cancer Patients: a Phase II Open Randomized Clinical Trial
Background: Whole-brain radiotherapy (WBRT) is the standard treatment for multiple brain
metastases (BM), in NSCLC patients who are not candidates for treatment with stereotactic
radiation body therapy. Hypoxia has been associated with chemo-radioresistance secondary to
Vascular Endothelial Growth Factor Receptor (VEGFR) induced by Hypoxia Induced Factor (HIF).
Nitroglycerin (NTG) can reduce HIF-1 alfa in tissues, and this may have anti-angiogenic,
pro-apoptotic and anti-efflux effects. In this phase II study, we evaluated the effect of
transdermal nitroglycerin (TN) on intracranial progression-free survival (ICPFS), objective
response rate (ORR) and overall survival (OS) of NSCLC patients with BM.
Material and methods: We performed an open-label, phase II clinical trial among ninety-six
histologically confirmed NSCLC patients with BM. Patients were randomized 1:1 to receive NTG
plus WBRT or WBRT alone. ORR and ICPFS were evaluated by MRI by two independent, blinded
radio-oncologists.
Non-small cell Lung cancer (NSCLC) is the most frequent type of lung cancer worldwide. Brain
metastases (BM) are the most frequent neurological complications related to NSCLC and it is
estimated that 20% to 40% of these patients will present them at some point during the
progression of their disease, leading to a poor prognosis.
As only a selected group of NSCLC patients with single metastases or small lesions are
candidates for surgical resection or SBRT, the standard treatment for multiple BM is
whole-brain radiation therapy (WBRT). Although 80% of the patients who receive WRBT can
initially respond to treatment, 50% of these patients will have disease progression. This
further has been related to genetic and environmental factors that may lead to
radio-resistance, which is the capacity of a cell to stand the effects of radiant energy. To
face this problem, other options such as chemotherapy or radio-sensitizers have shown slight
benefit in terms of progression-free survival (PFS) but not in overall survival (OS).
Different studies have suggested tumor microenvironment (TME) has an important role in
treatment response of BM-derived from melanoma and NSCLC. The demand for O2 by tumors during
cancer is an unsteady phenomenon, caused by continuous metabolic profile changes, immune
response activity, and TME interactions. Hypoxia occurs in most tumors and plays an important
role in tumor progression. In NSCLC exists a clear relationship between hypoxia and
radioresistance. Hence, there is interest into modulate TME hypoxia to improve treatment
response. Hypoxia regulates the expression of genes that encode growth factors such as
endothelin-1 (ET-1), growth factor-derived platelets-B (PDGF) and vascular endothelial growth
factor (VEGF), as well as genes that regulate the production of gas molecules such as nitric
oxide (NO) and carbon monoxide (CO). The hypoxia-inducible factor (HIF) is a transcription
factor that regulates the cellular response to hypoxia, functioning as a regulator of oxygen
homeostasis. Several studies have shown that over-expression of HIF-1α is capable of inducing
resistance to chemotherapy, radiotherapy and decreasing overall survival in NSCLC primary
tumors.
The administration of nitric oxide donors, such as nitroglycerin, reduces the tumor
resistance related to hypoxia by inducing the direct proteolysis of HIF-1α. In tumor cells
increases oxygen pressure, increased blood flow, activation of p53 and apoptosis have shown a
synergistic effect with ionizing irradiation in an experimental model. According to several
randomized phase II studies, the addition of transdermal nitroglycerin to vinorelbine and
cisplatin treatment can significantly improve the OS and time to progression in patients with
locally advanced non-small cell lung cancer. However, in phase III the addition of
nitroglycerin to carboplatin-based did not show benefit in PFS, OS and health-related quality
of life (PMID: 26347110). Therefore, the aim of this study was to assess, if the addition of
transdermal NTG to standard WRBT treatment among stage IV NSCLC patients with BM, could have
a significant impact in PFS and OS as primary end-point and disease control rate (DCR) and
overall response rate (ORR) as secondary endpoints.
METHODS Experimental design We conducted a phase II clinical trial with a parallel design
study among patients treated at the Instituto Nacional de Cancerología from January 2014 to
May 2017. The Median follows up was 18 months. Patients with histologically confirmed NSCLC
and documented BM defined as the presence of one or more intra-axial enhancing lesions on
gadolinium-enhanced brain magnetic resonance imaging (MRI) were included. Candidate patients
who underwent radiosurgery or surgical resection were excluded.
Sample size. The sample size calculation was estimated for a two-sample proportion difference
in ORR for NSCLC patients who received WBRT plus TN. Although in one of our previous studies
we found a difference of 40% in ORR among locally advanced NSCLC patients 30, we prefer to be
more conservative in our estimations taking into account our different study populations.
Thus, our sample estimation assumptions were performed for a difference in ORR (delta) of 30%
between population (p1= 25% vs p2= 65%) with a study power was set at 0.80 and the two-sided
type I error (alpha) was set as 0.05. Therefore, the estimated sample number is 108 (54 per
group). We also add a 5% of extra patients, to prevent the possible loss of patients due to
the progression of the disease.
Endpoints. The primary outcome was overall response rate (ORR); Secondary endpoints were
disease control rate (DCR), intracranial progression-free survival (ICPFS) and overall
survival (OS). The radiographic response was assessed by two independent blinded radiologists
according to the Response Evaluation Criteria in Solid Tumors (RECIST) guideline version 1.1
by comparing the pre-and post-treatment images. Any in-field tumor progression or the
appearance of new malignant lesions denoted progressive disease. ORR was defined as the sum
of complete and partial response, whereas DCR was defined as the sum of ORR and stable
disease. For PFS, time to event was defined and calculated from the date of randomization
until radiographic disease progression, treatment discontinuation due to either unacceptable
toxicity death by any cause. For OS, time-to-event was defined as time from randomization
until death by any cause or loss to follow-up. Observations for patients who did not
experience the event were censored at patient-specific last follow-up. Finally, treatment
toxicity was evaluated with CTCAE criteria.
Intervention assignment and informed consent Patients were randomized 1:1 and allocated to
either the control arm who received whole-brain radiotherapy (WBRT) (30 Gy in 10 fractions,
in 10 days of treatment) or the experimental arm who received WBRT and the addition 36 mg of
transdermal nitroglycerin (TN) with release of 10 mg in 24 hours, for 24 hours with a 12-hour
rest interval (to avoid saturation of receptors). All patients signed the informed consent
letter, prior to any procedure. The project was approved by the local scientific and
bioethics committee (number). Further details can be found in clinicaltrials.gov (NCT¿?).
Patients received chemotherapy (CT) platinum-based or TKI according to mutation status.
Response assessment BM was documented among all patients at NSCLC diagnosis and staging by
either computed tomography (CT) of the head gadolinium-enhanced brain magnetic resonance
imaging (MRI) at baseline. Then, all patients underwent an MRI prior to treatment and at the
end of treatment (median 15 days). The imaging studies were carried out in a Signa HDxt 1.5 T
scanner (GE Healthcare). They include conventional sequences in multiple planes, T1, T2, T2
Flair, Echo gradient, Diffusion, volumetric acquisition in axial plane T1 Spoiled Gradient
recalled (SPGR), without contrast and after this (Gadolinium). Cerebral perfusion was
evaluated by echo-planar sequence with the following parameters: multiphase (25 - 45 phases)
with an acquisition time of 1:10, with a PSI of 5 and a flow rate of 5; with a volume of 15ml
of gadolinium (+) 20ml of saline at a speed of 5ml/second.
The radiographic response of intracranial tumors was assessed by two blinded and independent
blinded radio-oncologist (MY & FM) according to the Response Evaluation Criteria in Solid
Tumors (RECIST) guideline version 1.1 by comparing the pre-and post-treatment intracranial
images [15]. Any in-field tumor progression or the appearance of new malignant lesions
denoted progressive disease. Objective response was defined as the sum of complete and
partial response.
DNA Extraction Biopsies were taken using CT-guided tru-cut or bronchoscopy and were analyzed
by the pathology department for their histologic diagnosis and neoplastic cellularity
quantification (>50%); they were later embedded in paraffin until processed for DNA
extraction. Genomic DNA was extracted from the areas of paraffin slides using a standard
procedure and a QIAamp DNA FFPE tissue kit (TMQIAGEN), following manufacturer's instructions.
Determination of EGFR and KRAS mutational status EGFR exon 19, exon 20 and exon 21 gene
mutations were detected using the Therascreen RGQ PCR kit (TMQIAGEN, Scorpions ARMS method),
which combines both the ARMS and Scorpions technologies for detecting the mutations by
real-time polymerase chain reactions (PCR). Real-time PCR was performed using a Rotor-Gene Q
5plex HRM (TMQIAGEN), following manufacturer's instructions.
Statistical analysis Continuous variables were summarized as arithmetic means or medians,
with standard deviation or interquartile range for descriptive purposes according to normal
data distribution assessed by means of the Shapiro-Swilk test. Meanwhile, categorical
variables were summarized as frequencies and percentages. For dichotomous outcomes (eg.
objective response rate (ORR), disease control rate (DCR), the percentage (incidence rate)
and 95% CI are presented. Inferential comparisons were made using the T-test or two-way ANOVA
for continuous variables and with either Mann-Whitney U test or Kruskall-Wallis test,
conforming to the data distribution and a number of groups. The χ2 test or Fisher exact test
was used for assessing the statistical significance of categorical variables. To address the
effect of treatment of secondary outcomes (eg. OS, ICPFS) we performed univariate survival
analysis. Time-to-event was estimated using the Kaplan-Meier method and comparisons among the
subgroups were analyzed using the log-rank test. For survival curve analysis, all the
variables were dichotomized according to their median. After we performed a forward stepwise
Multivariable Cox regression model and hazard ratios (HR) were calculated along with their
corresponding 95% CIs as a measure of association. Statistically and clinically significant
and borderline significant variables (p <.10) were included for the adjustment in the
multivariate Cox regression model. Significantly Kaplan-Meir curves were plotted. Statistical
significance was determined as P <0.05 using a 2-tailed test. Stata software version 14 was
used for all statistical analyses.
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