Genomic Predictors of Leptomeningeal Disease Development among Patients with Brain Metastases

PURPOSE/OBJECTIVE(S)

Leptomeningeal disease (LMD) is associated with significant neurologic symptomatology, functional decline, and generally, a very poor prognosis. Clinical characteristics of patients with parenchymal brain metastases have limited potential in predicting who will subsequently develop LMD. We hypothesized that genomic alterations may predict which patients with intracranial disease are at highest risk for developing LMD and sought to identify DNA-based genomic alterations among a targeted panel of cancer-related genes that may increase a patient's risk for LMD.

MATERIALS/METHODS

We identified 810 patients with parenchymal brain metastases secondary to solid tumor primaries without LMD at diagnosis of initial intracranial disease managed at a tertiary cancer center (2003-2020) for whom next-generation sequencing panel data (OncoPanel, 239 genes) were available on at least one extracranial or intracranial tumor specimen. Fine/Gray's competing risks regression was utilized to compare risk for LMD development among patients with vs. without somatic alterations of likely clinical/biological significance, delineated via OncoKB, across 96 genes with a mutational frequency ≥0.5% in the patient cohort. Genes with a q-value<0.10 and hazard ratio (HR)>1 were considered predictive of LMD risk; patients were dichotomized into "high-risk" vs. "low-risk" of LMD development based on the presence or absence of mutations in any one of these predictive genes.

RESULTS

Genomic alterations of potential biological significance in MAPK1 (gain-of-function), CDH1 (loss-of-function), and SF3B1 (switch-of-function) were more common among patients who developed LMD vs. not (MAPK1, 3.6% vs. 0.4%; CDH1, 3.6% vs. 0.8%; SF3B1, 3.6% vs. 0.6%, respectively) and were each associated with an increased risk for LMD development (q-value<0.10 in all cases). On multivariable Fine/Gray's competing risk regression, "high-risk" patients with genomic alterations in any of these three genes (HR 4.32 [1.93-9.67], p<0.001), Karnofsky performance status <90 (HR 1.76 [1.11-2.79], p<0.001), and lack of local, brain-directed therapy as part of intracranial disease management (HR 2.97 [1.48-5.96], p<0.002) were associated with increased risk of LMD; age and primary tumor site were not associated with LMD risk (p>0.05).

CONCLUSION

Utilizing a targeted panel of genes with a known role in cancer pathogenesis, we identified genomic alterations in three genes as being predictive of LMD development. If validated in independent datasets, development of clinical trials exploring inhibition of pathways affected by these genomic alterations may be warranted with the goal of LMD prevention and targeted treatment among particularly high-risk cohorts. To our knowledge, this represents the first study to identify potentially actionable alterations as predictive of leptomeningeal disease development among patients with brain metastases.

Factors Associated with Stereotactic Radiation Plan Revision in Prospective Peer Review

PURPOSE/OBJECTIVE(S)

Stereotactic radiotherapy (SR) is highly effective but has risks for serious toxicity. We sought to identify risk factors for SR plans requiring revision in a comprehensive, prospective peer review program conducted across a network of affiliated radiation centers. We hypothesized that increased physician experience and SR case volume would be associated with lower rates of SR plan revision.

MATERIALS/METHODS

Weekly peer review rounds were conducted to review SR cases for image fusion, contours, plan, and dose constraints, all prior to start of radiation. Cases recommended for revision were recorded and tracked prospectively. Factors potentially associated with case revision including body site, SR type, physician experience, and physician case load were assessed for significance using univariate and multivariable logistic regression.

RESULTS

From March 2019 to January 2023, 1,015 SR cases were prospectively reviewed, including 312 brain stereotactic radiosurgery (SRS), 190 multi-fraction brain SRS (fSRS), and 513 stereotactic body radiotherapy (SBRT). Revision was recommended in 177 cases (17%). The yearly revision rate was 21% in 2019, 16% in 2020, 17% in 2021, and 18% in 2022. There were 13 individual treating physicians with a median of 5 years' experience (range: 2-18 years), measured at the time of each SR case review. Physicians were categorized as junior (< = 2 years of experience), mid-career (3-9 years), or senior (> = 10 years). The physician's SR case volume in the preceding 3 months (median 25 cases) was dichotomized as low volume (< = 25) or high volume (>25). Logistic regression results are shown in Table 1. Statistical significance was determined by p <0.05.

CONCLUSION

SR plans utilizing SRS (as opposed to SBRT) and treated by physicians with high case volume had lower revision rates. Junior attendings had higher revision rates. These data imply a high value to peer review for junior attendings and for those with low SR case volume. Adequate case volume may be a critical factor for safe delivery of SR, analogous to surgical literature. Annual revision rates in the program remained stable over time, demonstrating the ongoing importance of an effective peer review program for SR.

A Genomic Score to Predict Local Control among Patients with Brain Metastases Managed with Radiation

PURPOSE/OBJECTIVE(S)

Clinical predictors of local recurrence following radiation among patients with brain metastases (BrM) provide limited explanatory power. As a result, radiation doses and fractionation schemes are relatively homogeneous and prescribed with a "one-size-fits-all" approach. We hypothesized that tumor-specific genomic alterations may underlie radiation sensitivity among patients with BrM and sought to develop a DNA-based signature of radiation-based efficacy in this patient population, utilizing genes that are readily testable in modern-day assays, to identify subpopulations at greater vs. lesser risk of recurrence.

MATERIALS/METHODS

We identified 570 patients with 1,487 distinct BrM managed with whole-brain (WBRT) or stereotactic radiation therapy (SRS/SRT) at a tertiary cancer center (2013-2020) for whom next-generation sequencing panel data (OncoPanel, 239 genes) were available on at least one extracranial or intracranial tumor specimen. Fine/Gray's competing risks regression was utilized to compare local recurrence on a per-metastasis level among patients with vs. without somatic alterations of likely biological significance across 84 OncoPanel genes with a mutational frequency of >0.5%. Genes with a q-value<0.10 were utilized to develop a numeric "Brain-Radiation Prediction Score" ("Brain-RPS") to quantify local recurrence risk.

RESULTS

Genomic alterations of potential biological relevance in 11 (ATM, MYCL, PALB2, FAS, PRDM1, PAX5, CDKN1B, EZH2, NBN, DIS3, MDM4) and two genes (FBXW7 and AURKA) were associated with a decreased or increased risk of local recurrence, respectively (q-value<0.10). Weighted scores corresponding to the strength of association with local failure for each gene were summed to calculate a patient-level Brain-RPS. On multivariable Fine/Gray's competing risks regression, Brain-RPS [1.66 (1.44-1.92, p<0.001)], metastasis-associated edema [1.89 (1.38-2.59), p<0.001], and receipt of WBRT without SRS/SRT or neurosurgical resection [2.73 (1.78-4.20), p<0.001] were independent predictors of local failure.

CONCLUSION

Utilizing a targeted panel of genes with a known role in cancer pathogenesis, we developed a genomic score that can be calculated from an extracranial or intracranial site to quantify local recurrence risk following brain-directed radiation. Prior attempts to develop a biomarker-based radiation response signature have not focused on patients with BrM and have primarily relied on RNA-based measures of radiosensitivity, limiting their utility in real-world clinical practice for this patient population. To our knowledge, this represents the first study to systemically correlate DNA-based alterations with radiation-based outcomes among patients with BrM. If validated, Brain-RPS has potential to facilitate clinical trials aimed at genome-based personalization of radiation treatment among patients with BrM.

Clinical Utility of Dual Phase FDG PET for Distinguishing Tumor Progression from Radionecrosis in the Modern Era

PURPOSE/OBJECTIVE(S)

Dual-phase PET CT, a technique by which two PET/CT scans are taken hours apart, has previously shown utility in differentiating radionecrosis (RN) from tumor progression (TP) after radiation for brain metastases. We sought to validate the utility of this technique in an independent, contemporary patient cohort. Understanding the difficulty of validation without the gold standard of pathologic confirmation in a majority of cases, we hypothesized that a dual-phase PET/CT indicating likely RN would correlate with improved overall survival (OS).

MATERIALS/METHODS

We performed a retrospective cohort study of all patients who received dual-phase FDG-PET between April 2015 and January 2023 at a single center for the purpose of distinguishing RN from TP in brain metastases previously treated with radiation. Scans were classified as indicating likely RN (dpPET-RN), likely TP (dpPET-TP), or unclear (dpPET-Unc) based on final radiology report. A Kaplan Meier (K-M) analysis was performed to evaluate differences in survival among the different dual-phase PET finding categories. An alpha level of 0.05 in the log-rank test was used to determine statistical significance.

RESULTS

We identified 36 patients who met inclusion criteria. All patients had received prior radiation - stereotactic radiosurgery (SRS), whole brain radiotherapy (WBRT) or both- to the lesion, and 21 (58%) had received surgery at some point prior to the dual phase PET CT. One patient received brachytherapy. Median time from the most recent course of radiation until dual-phase PET was 294 days, while median time from most recent surgery to dual-phase PET was 379 days. 14/36 (39%) of scans were called as dpPET-TP,15/36 (42%) were dpPET-RN, and 7/36 (19%) were dpPET-Unc. There were 10 cases where pathology was available after subsequent resection of the lesion. Five of the 10 path reports were concordant with the dual phase PET read, 5 were discordant. On K-M, median survival was 11 months (95% CI: 7.8 to 14.2 months) for dpPET-TP patients, 18 months (95% CI: 7.9 to 33.5 months) for dpPET-RN, and 12 months (95% CI: 0.0 to 51.2 months) for dpPET-Unc. On log rank testing, differences in the survival distribution for the different groups of dual-phase FDG-PET results were not statistically significant, χ2(2) = 4.085, p = .130.

CONCLUSION

Dual-phase PET CT has been proposed as a useful tool for distinguishing TP from RN after prior radiation. In the small subset of cases from our study with pathologic confirmation of outcomes, dual-phase PET failed to show high concordance with pathology. Although the dpPET-RN cohort had numerically superior OS compared to the dpPET-TP and dpPET-unc groups, this result was not statistically significant. Further independent validation of this imaging technique is warranted before it can be relied upon for routine clinical management.

Whole brain radiotherapy after stereotactic radiosurgery or surgical resection among patients with one to three brain metastases and favorable prognoses: a secondary analysis of EORTC 22952-26001

Background

The absence of a survival benefit for whole brain radiotherapy (WBRT) among randomized trials has been attributed to a competing risk of death from extracranial disease. We re-analyzed EORTC 22952 to assess the impact of WBRT on survival for patients with controlled extracranial disease or favorable prognoses.

Patients and methods

We utilized Cox regression, landmark analysis, and the Kaplan-Meier method to evaluate the impact of WBRT on survival accounting for (i) extracranial progression as a time-dependent covariate in all patients and (ii) diagnosis-specific graded prognostic assessment (GPA) score in patients with primary non-small-cell lung cancer (NSCLC).

Results

A total of 329 patients treated per-protocol were included for analysis with a median follow up of 26 months. One hundred and fifteen (35%) patients had no extracranial progression; 70 (21%) patients had progression <90 days, 65 (20%) between 90 and 180 days, and 79 (24%) patients >180 days from randomization. There was no difference in the model-based risk of death in the WBRT group before [hazard ratio (HR) (95% CI)=0.70 (0.45-1.11), P = 0.133), or after [HR (95% CI)=1.20 (0.89-1.61), P = 0.214] extracranial progression. Among 177 patients with NSCLC, 175 had data available for GPA calculation. There was no significant survival benefit to WBRT among NSCLC patients with favorable GPA scores [HR (95% CI)=1.10 (0.68-1.79)] or unfavorable GPA scores [HR (95% CI)=1.11 (0.71-1.76)].

Conclusions

Among patients with limited extracranial disease and one to three brain metastases at enrollment, we found no significant survival benefit to WBRT among NSCLC patients with favorable GPA scores or patients with any histology and controlled extracranial disease status. This exploratory analysis of phase III data supports the practice of omitting WBRT for patients with limited brain metastases undergoing SRS and close surveillance.

Clinical Trials Number

NCT00002899.

Medical androgen deprivation therapy and increased non-cancer mortality in non-metastatic prostate cancer patients aged ≥66 years

PURPOSE

To examine the potential relationship between androgen deprivation therapy and other-cause mortality (OCM) in patients with prostate cancer treated with medical primary-androgen deprivation therapy, prostatectomy, or radiation.

METHODS

A total of 137,524 patients with non-metastatic PCa treated between 1995 and 2009 within the Surveillance Epidemiology and End Results Medicare-linked database were included. Cox-regression analysis tested the association of ADT with OCM. A 40-item comorbidity score was used for adjustment.

RESULTS

Overall, 9.3% of patients harbored stage III-IV disease, and 57.7% of patients received ADT. The mean duration of ADT exposure was 22.9 months (median: 9.1; IQR: 2.8-31.5). Mean and median follow-up were 66.9, and 60.4 months, respectively. At 10 years, overall-OCM rate was 36.5%; it was 30.6% in patients treated without ADT vs. 40.1% in patients treated with ADT (p < 0.001). In multivariable-analysis, ADT was associated with an increased risk of OCM (Hazard-ratio [HR]: 1.11, 95% Confidence-interval [95% CI]: 1.08-1.13). Patients with no comorbidity (10-year OCM excess risk: 9%) were more subject to harm from ADT than patients with high comorbidity (10-year OCM excess risk: 4.7%).

CONCLUSIONS

In patients with PCa, treatment with medical ADT may increase the risk of mortality due to causes other than PCa. Whether this is a simple association or a cause-effect relationship is unknown and warrants further study in prospective studies.

Incidence and determinants of 1-month mortality after cancer-directed surgery

BACKGROUND

Death within 1 month of surgery is considered treatment related and serves as an important health care quality metric. We sought to identify the incidence of and factors associated with 1-month mortality after cancer-directed surgery.

PATIENTS AND METHODS

We used the Surveillance, Epidemiology and End Results Program to study a cohort of 1 110 236 patients diagnosed from 2004 to 2011 with cancers that are among the 10 most common or most fatal who received cancer-directed surgery. Multivariable logistic regression analyses were used to identify factors associated with 1-month mortality after cancer-directed surgery.

RESULTS

A total of 53 498 patients (4.8%) died within 1 month of cancer-directed surgery. Patients who were married, insured, or who had a top 50th percentile income or educational status had lower odds of 1-month mortality from cancer-directed surgery {[adjusted odds ratio (AOR) 0.80; 95% confidence interval (CI) 0.79-0.82; P < 0.001], (AOR 0.88; 95% CI 0.82-0.94; P < 0.001), (AOR 0.95; 95% CI 0.93-0.97; P < 0.001), and (AOR 0.98; 95% CI 0.96-0.99; P = 0.043), respectively}. Patients who were non-white minority, male, or older (per year increase), or who had advanced tumor stage 4 disease all had a higher risk of 1-month mortality after cancer-directed surgery, with AORs of 1.13 (95% CI 1.11-1.15), P < 0.001; 1.11 (95% CI 1.08-1.13), P < 0.001; 1.02 (95% 1.02-1.03), P < 0.001; and 1.89 (95% CI 1.82-1.95), P < 0.001 respectively.

CONCLUSIONS

Unmarried, uninsured, non-white, male, older, less educated, and poorer patients were all at a significantly higher risk for death within 1 month of cancer-directed surgery. Efforts to reduce 1-month surgical mortality and eliminate sociodemographic disparities in this adverse outcome could significantly improve survival among patients with cancer.