PATH-13. SEX-LINKED TUMORAL MGMT STATUS AND OUTCOMES IN NEWLY DIAGNOSED GLIOBLASTOMA

INTRO/OBJECTIVE

Glioblastoma (GBM) and MGMT have been reported to have sexual dimorphism. The primary objective of this study was to analyze the impact and association between sex and MGMT status on progression-free survival (PFS) and overall survival (OS) in patients with newly diagnosed GBM.

METHODS

582 patients with newly diagnosed GBM who underwent first surgical intervention at a single tertiary care institution between 2012 and 2018 were reviewed. Adults with documented methylated (≥ 12) and un-methylated (≤ 7) MGMT status were included. A Kaplan-Meier and Cox proportional hazard models were used to analyze the association between sex and MGMT status on PFS and OS.

RESULTS

464 adult patients (median age 63.4, 36.6% female) had documented MGMT status. Overall rate of MGMT methylated patients was 42.5%, while females were more often methylated than males (52.1% vs 37.4%, p=0.004). MGMT methylated compared to un-methylated females (median: 12.8 vs 7.4 months; 1-yr: 53% vs 27%) had a greater PFS benefit than males (median: 9.6 vs 6.8 months; 1-yr: 44% vs 23%). OS was significantly improved in MGMT methylated compared to un-methylated patients among females (p=0.001) but not among males (p=0.22). Among MGMT methylated patients, females had significantly better OS compared to males (median: 18.7 vs 12.4 months; 2-yr OS: 36.8% vs 24.3%, p=0.03). Although statistically not significant, a similar pattern was observed on PFS (median: 12.8 vs 9.6 months; 1-yr PFS: 52.6% vs 44.4%). Compared to MGMT methylated females, MGMT methylated males had a PFS HR=1.22 (95% CI=0.80 – 1.85, p=0.36), and an OS HR=1.45 (95% CI=1.03 – 2.04, p=0.032).

CONCLUSION

MGMT methylation is more common in females and methylation had a larger impact on both PFS and OS in females compared to males. These analyses highlight the need to further investigate sex differences that can inform clinical management of GBM.

THER-09. IMPACT OF KRAS MUTATION STATUS ON THE EFFICACY OF IMMUNOTHERAPY IN LUNG CANCER BRAIN METASTASES

BACKGROUND: Immunotherapy is increasingly used in patients with non-small cell lung cancer brain metastases (NSCLCBM). KRAS mutations are associated with worse prognosis and there is no FDA approved targeted therapy. KRAS mutations are associated with increased expression of PD-L1. We evaluated the outcomes of NSCLCBM with KRAS mutations treated with immune checkpoint inhibitors (ICI). METHODS: We reviewed 800 patients with NSCLCBM treated at our tertiary care center. 226 had known KRAS mutational status, 121 of which received immunotherapy. Overall survival (OS) was calculated from either the start of immunotherapy (when both groups received immunotherapy) or from the date of diagnosis of brain metastasis. Kaplan-Meier method and Cox Proportional hazard model were utilized to determine differences in OS and the Chi-square test was utilized to determine differences in PD-L1 expression. RESULTS: In 109 patients where both KRAS and PD-L1 status were known, KRAS mutations had greater PD-L1 expression (80.1% vs 61.9% positive, p=0.04). There was no difference in OS between KRAS mutant vs KRAS wild-type patients treated with immunotherapy. Median survival from the start of immunotherapy was 15.6 vs 15.5 months respectively (p=0.7), after adjusting for age, KPS, lesion number and extra-cranial metastasis (HR = .91, p=.7). Patients with KRAS mutations treated with immunotherapy versus those who received chemotherapy had a 1-year OS from the diagnosis of brain metastasis of 60.9% vs 38.7% respectively (trending towards significance, p=0.05). KRAS wild-type patients treated with immunotherapy versus those who did not receive immunotherapy had a 1-year OS from the diagnosis of brain metastasis of 61.9% vs 62.5% (p=0.85), respectively. DISCUSSION: KRAS mutations are associated with increased PD-L1 expression. Use of immunotherapy negates the poor outcomes seen traditionally in patients with NSCLCBM and KRAS mutations and it improves survival compared to use of chemotherapy. Our experience supports the use of immunotherapy in these patients.

THER-10. IMPACT OF BRAF MUTATIONAL STATUS ON THE EFFICACY OF IMMUNOTHERAPY FOR MELANOMA BRAIN METASTASES

BACKGROUND: BRAF mutations occur in 50% of melanoma patients. Targeted agents – BRAF and MEK inhibitors and immunotherapy improve survival of melanoma patients with BRAF mutations. These agents have intracranial efficacy as shown in clinical trials. However, the efficacy of immunotherapies (immune checkpoint blockade) in melanoma brain metastases and the correlation with BRAF status is not as well characterized. METHODS: We reviewed 351 patients with melanoma brain metastases treated at our tertiary care center between 2000 and 2018, 75 of which received immunotherapy with known BRAF mutational status. Two-year, 5-year, and median overall survival (OS) was calculated from the start of immunotherapy to compare the efficacy of immunotherapy in BRAF mutant and BRAF wild type patients using the log-rank test. RESULTS: At the time of diagnosis of brain metastasis, the median age was 61 (23–87) years, median KPS was 80 (50–100), number of intracranial lesions was 2 (1–15), and 79% had extra-cranial metastases. Sixty-three patients were treated with stereotactic radiosurgery (SRS), 27 underwent whole brain radiation (WBRT) and 21 underwent surgery. When treated with immunotherapy, BRAF mutant and BRAF wild type median survival was 15.7 months (95% CI=9.4 – 42.4) and 6.9 (95% CI=4.1– 26.7) months (p-value=0.205), respectively. Two-year BRAF mutant and BRAF wild type survival was 35% (95% CI=21 – 58) and 28% (95% CI=16 – 51), and 5-year survival was 22% (95% CI=10 – 46) and 23% (95% CI=11 – 47), respectively. CONCLUSIONS: Twenty percent of patients with BRAF mutant and BRAF wild-type patients treated with immunotherapy derive a long-term benefit from immunotherapy and multimodality treatment and are alive 5 years from diagnosis of brain metastases. This was rarely seen in the pre-immunotherapy era in melanoma brain metastases. There was no difference in outcome based on the BRAF mutational status with use of immunotherapy in melanoma brain metastases.

THER-16. EFFICACY OF UPFRONT IMMUNE CHECKPOINT INHIBITORS IN LUNG CANCER BRAIN METASTASIS

INTRODUCTION: Immune checkpoint inhibitors (ICI) have resulted in improved outcomes in a subset of patients with lung cancer. However, data describing the efficacy of ICI in lung cancer brain metastasis (LCBM) is limited. We analyzed overall survival (OS) in patients with LCBM treated with upfront ICI, defined as having received ICI within 90 days of LCBM diagnosis, compared to non-ICI therapies. METHODS: We reviewed 665 patients with LCBM who were diagnosed between 2000 and 2018 at a major tertiary care institution. Of those patients, 240 received ICI, 164 of which received ICI after 90 days and 76 received ICI within 90 days. Propensity score (PS) was calculated using a logistic regression model including age, KPS, number of baseline brain lesions, and presence of extra-cranial metastasis (ECM) at the time of BM diagnosis. OS from BM diagnosis between PS matched cohorts were compared using Kaplan-Meier, the Log-Rank test, and Cox proportional hazards model. RESULTS: Prior to PS matching, median survival between ICI and non-ICI cohorts was not significantly different (10.9 months for both, p=0.81), although more ICI patients had ECM (57.1% vs 40.9%, p=0.006). Following PS matching, the ICI (n=76) and non-ICI (n=76) cohorts had a median age (62.4 vs 62.3 years), KPS (80 for both), lesion number (2 for both), and ECM (56.6% for both). Of matched patients, 94% received SRS, 52% received WBRT, and 29% underwent surgical resection. Compared to non-ICI, the ICI cohort has a 2-year OS hazard ratio, HR=0.87 (95% CI=0.58–1.31, p=0.51). Median and 1-year survival were not significantly different between ICI and non-ICI cohorts (median: 10.9 vs 9.1 months; 1-yr: 43.0% vs 42.4%). CONCLUSION: Patients with BM from primary lung cancer who received ICI within 90 days of their BM diagnosis did not have improvement in OS compared to patients who received non-ICI therapies.

THER-13. IMMUNOTHERAPY VERSUS STANDARD OF CARE IN MELANOMA BRAIN METASTASES WITH KNOWN BRAF STATUS

BACKGROUND: A mutation of the BRAF protein is seen in approximately 50% of melanoma patients. Immune checkpoint inhibitors (ICI) are standard therapy in melanoma patients independent of a patient’s BRAF status. The primary objective of this study is to investigate the impact of BRAF status in patients treated with ICI compared to non-ICI systemic therapy on overall survival (OS) in patients with melanoma brain metastasis (MBM). METHODS: We reviewed 351 patients with MBM treated at our tertiary care center between 2000 and 2018. Of these, 144 had known BRAF status, 71 of which were BRAF mutant and 73 were BRAF wild-type. OS was calculated from the date of diagnosis of brain metastasis to compare the efficacy of ICI to other systemic therapies. Many of these patients received multiple lines of treatment including targeted therapies at some point during their care. The log-rank test and Cox proportional hazard model was utilized to determine differences in OS. RESULTS: Eighty-four percent of patients received local therapy that included either surgery, stereotactic radiosurgery or whole brain radiation therapy. In BRAF wild-type patients, 40 received ICI and 33 underwent non-ICI systemic therapy with a median survival (5.6 vs 7.1 months) and 2-year survival (28% vs 32%), respectively (p=0.64). Of the BRAF mutant patients, 33 received ICI and 38 did not with a median survival (17.1 vs 9.0 months) and 2-year survival (36% and 19%), respectively (p=0.014). When controlling for age, KPS, ECM, and number of lesions, BRAF mutant MBM patients treated with ICI compared to non-ICI had an OS hazard ratio, HR=0.4 (95% CI=0.21 – 0.78, p=0.0069). CONCLUSIONS: ICI therapy in BRAF mutant MBM patients results in improved OS compared to those with non-ICI systemic therapy. No such difference was observed in the BRAF wild-type cohort.

THER-02. IMPACT OF SYSTEMIC THERAPY IN MELANOMA BRAIN METASTASIS

BACKGROUND: Melanoma brain metastasis is associated with a median overall survival (OS) of approximately 9 months. In recent years, management of melanoma brain metastases (MBM) by surgery and radiation [stereotactic radiosurgery (SRS) and whole brain radiation therapy (WBRT)] has been bolstered by targeted therapy and immune checkpoint inhibitors (ICI). METHODS: 351 patients, who underwent treatment for MBM at our tertiary care center from 2000 to 2018, were grouped into those that received chemotherapy, ICI, or targeted therapy. Thirty-four percent of patients treated with ICI had received other systemic therapies as well as part of their management. OS was calculated from the date of diagnosis of the brain metastases. The Kaplan Meier analysis was utilized to determine median OS and difference in OS was determined by utilizing the Cox proportional hazard model. RESULTS: The median survival after the diagnosis of brain metastasis was 10.4, 11.96, and 7.06 months in patients who received ICI, chemotherapy and targeted therapy respectively. A multivariate model was developed including the type of systemic therapy, presence of extracranial metastases, age, KPS and number of intracranial lesions. 114 patients underwent SRS alone, 56 underwent SRS and WBRT, 43 underwent SRS and surgical removal, 28 had surgical removal, SRS and WBRT, and 78 had no intracranial therapy. Compared to patients who received chemotherapy, patients who received immunotherapy had a hazard ratio, HR = 0.628 (confidence interval = 0.396 – 0.994, p-value = 0.047). Presence of EC metastases (HR= 1.25, p-value < .001), lower KPS (HR = .97, p-value < .0001) and multiple brain lesions (HR = 1.117, p-value < .0001) were associated with significantly worse OS. CONCLUSIONS: Addition of ICI significantly improves the OS in MBM compared to chemotherapy. Lower performance status, multiple brain metastases, and EC metastases are associated with poor OS.

Absolute lymphocyte count in patients with glioblastoma treated with temozolomide chemoradiation

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Background: Standard glioblastoma (GBM) management includes radiotherapy, chemotherapy, and steroids; all of which can result in immunosuppression and a low absolute lymphocyte count (ALC). Previous literature identified an association between low CD4 and worse progression free survival (PFS) and overall survival (OS). There remains a lack of research addressing predictors of immunosuppression in patients with GBM. The primary objective of this study is to identify the degree of immunosuppression, measured by ALC, in GBM patients receiving concurrent temozolomide chemoradiation (CRT). Secondary objectives include associations between ALC, PFS, and OS, and whether there are any predictors of immunosuppression in patients with GBM. Methods: We retrospectively reviewed 231 newly diagnosed GBM patients who underwent surgery followed by standard of care CRT. We also analyzed the association between ALC and age, sex, MGMT methylation status, and extent of surgical resection. ALC was collected at the time of surgery, CRT start date, and two, four, six, and ten weeks post-CRT start date. Common Terminology Criteria for Adverse Events (CTCAE) protocol version 5.0 was then used to grade low ALC as grade 0, 1, 2, 3, or 4. Results: Of the 231 patients analyzed, 139 were males, 74 underwent gross total resection of the tumor, 129 patients were less than 65 years, and 79 (42.5%) were MGMT methylated. 37 patients had grade 3-4 low ALC. In a univariate analysis, grade 3-4 low ALC at 4 weeks (±14 days) post-CRT start was associated with higher mortality (HR 1.54, P = 0.028) but had no significant association with PFS (HR 1.22, P = 0.29). Logistic regression analysis was used to identify risk factors for grade 3-4 low ALC and its association with survival. None of the risk factors that we tested such as age, gender, type of surgery, or molecular markers including MGMT, IDH, or EGFR were associated with low ALC. Conclusions: Our study demonstrated that patients with ALC grade 3 or 4 at 4 weeks (±14 days) of CRT had a significantly higher mortality (HR 1.54, P = 0.028) but had no significant association with PFS (HR 1.22, P = 0.29).

Albumin levels and Prognostic Nutritional Index in glioblastoma

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Background: Albumin levels are widely used to estimate patients’ nutritional status. Low perioperative albumin levels are associated with worse outcomes. Moreover, Prognostic Nutritional Index (PNI), which is calculated from serum albumin levels and peripheral blood lymphocyte count as follows: PNI = (Albumin x 10) + (0.005 x ALC), has been used to predict both short and long term outcomes in patients with wide variety of tumors. The primary objective of this study was to characterize perioperative albumin levels and PNI in newly diagnosed GBM patients. Secondary objectives included associations between albumin levels and PNI on progression free survival (PFS) and overall survival (OS). Methods: We retrospectively reviewed 568 newly diagnosed GBM patients who underwent surgery followed by standard of care chemoradiation. We analyzed the association between albumin and PNI on age, sex, MGMT methylation status, and extent of surgical resection on PFS and OS using a multivariate Cox proportional hazard model. Results: Of the 568 patients collected, 355 (62.5%) were males, 158 (27.8%) had gross total resection of the tumor, and 197(42.5%) were MGMT methylated. Both albumin and PNI were associated with OS but not PFS. The hazard ratio (HR) for OS among the top 2 quartiles of both albumin level and PNI were significantly higher than the bottom two quartiles. The median albumin level was 4.0 and the median PNI was 40. The point for significant high hazard ratio (HR) was around median value for both Albumin and PNI based on restricted cubic spine Cox regression models. The Kaplan-Meir (KM) estimated median OS was 15.2 months for albumin > 4, and 7.6 for albumin ≤4. The KM estimated median OS was 14.6 months for PNI > 40, and 5.7 for PNI≤40 (P logrank < 0.001 for both). While controlling for other factors that may also be associated with early death including age, gender, surgery type and MGMT status, HR = 1.9 (95% CI = 1.4- = 2.6) for Albumin < 4, and HR = 2.1 (95% CI = 1.5- 3.0) for PNI < 40 compared to their counterpart. Conclusions: Glioblastoma patients with perioperative albumin > 4 had a median OS of 15.2 months and 7.6 months for albumin ≤4, and a median OS of 14.6 months for PNI > 40 and 5.7 months for PNI≤40 (P logrank < 0.001 for both).

Impact of EGFR amplification status in newly diagnosed glioblastoma treated with Stupp protocol

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Background: Standard post-surgical glioblastoma (GBM) treatment, per Stupp protocol, includes six-weeks of concurrent Temozolomide chemoradiation followed by at least six cycles of adjuvant-Temozolomide. Previous investigations into epidermal growth factor receptor (EGFR) amplification as a prognostic factor in GBM have yielded contradicting results, requiring further investigation. The primary aim of this study was to determine the degree to which EGFR amplification, in newly diagnosed GBM, impacted progression free survival (PFS) and overall survival (OS). Methods: Data from 582 patients who underwent surgical intervention for GBM at a tertiary care institution between 2012 and 2018 were analyzed. Only adult patients who underwent treatment per Stupp protocol and had pathological analysis on EGFR and CEP7 were included. Amplification and non-amplification status was calculated by a ratio of EGFR/CEP7 > 2 and < 2, respectively. PFS and OS outcomes were compared using Cox proportional hazard models stratified by surgery type and sex. Results: Of the original 582 patients, 122 were treated per Stupp protocol and had documented EGFR analysis. Of patients who were EGFR amplified, 41 (58.5%) were male and 25 (48.1%) were female (p = 0.38) and median amplification was 1.07 and 1.16 (p < 0.001), respectively. EGFR non-amplified patients had a PFS hazard ratio, HR = 0.70 (95% CI = 0.44 – 1.12, p = 0.14); and an OS HR = 0.60 (95% CI = 0.35 – 1.03, p = 0.065). When the EGFR/CEP7 ratio was stratified by quartile, it was found that Q4 compared to Q1 (Q4 > 6.50 vs 0 < Q1 ≤ 1.06) had a PFS HR = 2.1 (95% CI = 1.11 – 4.07, p = 0.024); and an OS HR = 2.48 (95% CI = 1.10 – 5.60, p = 0.028). Conclusions: There was no statistical difference in prevalence of EGFR amplification by sex. However, despite statistical significance, there was minimal difference in median degree of amplification by sex (0.09). Trends begin to show that patients who were EGFR non-amplified had better PFS and OS outcomes than patients who were EGFR amplified, although this was not statistically significant. Patients with very high EGFR amplification (Q4) had significantly poorer PFS and OS outcomes than patients with very low EGFR amplification (Q1).

Trends and determinants of weight gains among OECD countries: an ecological study

OBJECTIVES

Obesity has become a global issue with abundant evidence to indicate that the prevalence of obesity in many nations has increased over time. The literature also reports a strong association between obesity and economic development, but the trend that obesity growth rates may converge over time has not been examined. We propose a conceptual framework and conduct an ecological analysis on the relationship between economic development and weight gain. We also test the hypothesis that weight gain converges among countries over time and examine determinants of weight gains.

STUDY DESIGN

This is a longitudinal study of 34 Organisation for Economic Cooperation and Development (OECD) countries in the years 1980-2008 using publicly available data.

METHODS

We apply a dynamic economic growth model to test the hypothesis that the rate of weight gains across countries may converge over time. We also investigate the determinants of weight gains using a longitudinal regression tree analysis.

RESULTS

We do not find evidence that the growth rates of body weight across countries converged for all countries. However, there were groups of countries in which the growth rates of body weight converge, with five groups for males and seven groups for females. The predicted growth rates of body weight peak when gross domestic product (GDP) per capita reaches US$47,000 for males and US$37,000 for females in OECD countries. National levels of consumption of sugar, fat and alcohol were the most important contributors to national weight gains.

CONCLUSION

National weight gains follow an inverse U-shape curve with economic development. Excessive calorie intake is the main contributor to weight gains.