Jim Zhong

Comparing Preoperative With Postoperative Stereotactic Radiosurgery for Resectable Brain Metastases: A Multi-institutional Analysis.

BACKGROUND Stereotactic radiosurgery (SRS) is an increasingly common modality used with surgery for resectable brain metastases (BM). OBJECTIVE To present a multi-institutional retrospective comparison of outcomes and toxicities of preoperative SRS (Pre-SRS) and postoperative SRS (Post-SRS). METHODS We reviewed the records of patients who underwent resection of BM and either Pre-SRS or Post-SRS alone between 2005 and 2013 at 2 institutions. Pre-SRS used a dose-reduction strategy based on tumor size, with planned resection within 48 hours. Cumulative incidence with competing risks was used to determine estimated rates. RESULTS A total of 180 patients underwent surgical resection for 189 BM: 66 (36.7%) underwent Pre-SRS and 114 (63.3%) underwent Post-SRS. Baseline patient characteristics were balanced except for higher rates of performance status 0 (62.1% vs 28.9%, P < .001) and primary breast cancer (27.2% vs 10.5%, P = .010) for Pre-SRS. Pre-SRS had lower median planning target volume margin (0 mm vs 2 mm) and peripheral dose (14.5 Gy vs 18 Gy), but similar gross tumor volume (8.3 mL vs 9.2 mL, P = .85). The median imaging follow-up period was 24.6 months for alive patients. Multivariable analyses revealed no difference between groups for overall survival (P = .1), local recurrence (P = .24), and distant brain recurrence (P = .75). Post-SRS was associated with significantly higher rates of leptomeningeal disease (2 years: 16.6% vs 3.2%, P = .010) and symptomatic radiation necrosis (2 years: 16.4% vs 4.9%, P = .010). CONCLUSION Pre-SRS and Post-SRS for resected BM provide similarly favorable rates of local recurrence, distant brain recurrence, and overall survival, but with significantly lower rates of symptomatic radiation necrosis and leptomeningeal disease in the Pre-SRS cohort. A prospective clinical trial comparing these treatment approaches is warranted. ABBREVIATIONS BM, brain metastasesCI, confidence intervalCTV, clinical target volumeDBR, distant brain recurrenceGTV, gross tumor volumeLC, local controlLMD, leptomeningeal diseaseLR, local recurrenceMVA, multivariable analysisOS, overall survivalPost-SRS, postoperative stereotactic radiosurgeryPre-SRS, preoperative stereotactic radiosurgeryPTV, planning target volumeRN, radiation necrosisSRN, symptomatic radiation necrosisSRS, stereotactic radiosurgeryWBRT, whole-brain radiation therapy.

Bevacizumab-induced hypertension is a predictive marker for improved outcomes in patients with recurrent glioblastoma treated with bevacizumab

Bevacizumab is a monoclonal antibody targeting vascular endothelial growth factor and is approved for the treatment of patients with recurrent glioblastoma (GBM). Previous authors have reported differential response to bevacizumab on an individual basis. Bevacizumab‐induced hypertension is a well‐documented side effect, and some reports have suggested this occurrence to be related to treatment outcome in other cancers. In the current study, the authors analyzed patients with recurrent GBM who were treated with bevacizumab based on whether the patients developed drug‐induced hypertension.

A Targeted Genetic Modifier Screen Links the SWI2/SNF2 Protein Domino to Growth and Autophagy Genes in Drosophila melanogaster

Targeted genetic studies can facilitate phenotypic analyses and provide important insights into development and other complex processes. The SWI2/SNF2 DNA-dependent ATPase Domino (Dom) of Drosophila melanogaster, a component of the Tip60 acetyltransferase complex, has been associated with a wide spectrum of cellular processes at multiple developmental stages. These include hematopoiesis, cell proliferation, homeotic gene regulation, histone exchange during DNA repair, and Notch signaling. To explore the wider gene network associated with Dom action, we used RNAi directed against domino (dom) to mediate loss-of-function at the wing margin, a tissue that is readily scored for phenotypic changes. Dom RNAi driven through GAL4-UAS elicited dominant wing nicking that responded phenotypically to the dose of dom and other loci known to function with dom. We screened for phenotypic modifiers of this wing phenotype among 2500 transpositions of the EP P element and found both enhancers and suppressors. Several classes of modifier were obtained, including those encoding transcription factors, RNA regulatory proteins, and factors that regulate cell growth, proliferation and autophagy, a lysosomal degradation pathway that affects cell growth under conditions of starvation and stress. Our analysis is consistent with prior studies, suggesting that Dom acts pleiotropically as a positive effector of Notch signaling and a repressor of proliferation. This genetic system should facilitate screens for additional loci associated with Dom function, and complement biochemical approaches to their regulatory activity.

The role of adjuvant radiotherapy in pathologically lymph node positive prostate cancer

Postoperative management of prostate cancer with lymph node involvement (LNI) is controversial. Retrospective evidence supports the selective use of radiotherapy (RT) after extended pelvic lymph node dissection. It is unclear whether this is generalizable to practice in the United States, where extended dissection is uncommon. The authors identified patients with LNI who potentially could derive a survival benefit with adjuvant RT plus androgen‐deprivation therapy (ADT).

Can we eliminate neoadjuvant chemoradiotherapy in favor of neoadjuvant multiagent chemotherapy for select stage II/III rectal adenocarcinomas: Analysis of the National Cancer Database

Stage II and III rectal cancers have been effectively treated with neoadjuvant chemoradiotherapy (NCRT) followed by definitive resection. Advancements in surgical technique and systemic therapy have prompted investigation of neoadjuvant multiagent chemotherapy (NMAC) regimens with the elimination of radiation (RT). The objective of the current study was to investigate factors that predict for the use of NCRT versus NMAC and compare outcomes using the National Cancer Data Base (NCDB) for select stage II and III rectal cancers.

Targeted gain-of-function screening in Drosophila using GAL4-UAS and random transposon insertions.

Alterations in the activity level or temporal expression of key signalling genes elicit profound patterning effects during development. Consequently, gain-of-function genetic schemes that overexpress or misexpress such loci can identify novel candidates for functions essential for a developmental process. GAL4-Upstream Activating Sequence (UAS)-targeted regulation of gene expression in Drosophila has allowed rapid analyses of coding sequences for potential roles in specific tissues at particular developmental stages. GAL4 has also been combined with randomly mobilized transposons capable of UAS-directed misexpression or overexpression of flanking sequences. This combination has produced a genetic screening system that can uncover novel loci refractory to standard loss of function genetic approaches, such as redundant genes. Available libraries of strains with sequenced insertion sites can allow direct correlation of phenotypes to genetic function. These techniques have also been applied to genetic interaction screening, where a GAL4 driver and UAS-regulated insertion collection are combined with an extant mutant genotype. In this article, we summarize studies that have utilized GAL4-UAS overexpression or misexpression of random loci to screen for candidates involved in specific developmental processes.

Outcomes for patients with locally advanced pancreatic adenocarcinoma treated with stereotactic body radiation therapy versus conventionally fractionated radiation.

As systemic therapy has improved for locally advanced pancreatic cancer (LAPC), efforts to improve local control with optimal radiotherapy may be critical. Although conventionally fractionated radiation therapy (CFRT) has more recently shown a limited role in LAPC, stereotactic body radiation therapy (SBRT) is an emerging approach with promising results. With no studies to date comparing SBRT with CFRT for LAPC, this study used the National Cancer Data Base (NCDB) to evaluate these 2 modalities.

Brainstem dose is associated with patient-reported acute fatigue in head and neck cancer radiation therapy

BACKGROUND AND PURPOSE Radiation (RT) dose to the central nervous system (CNS) has been implicated as a contributor to treatment-related fatigue in head and neck cancer (HNC) patients undergoing radiation therapy (RT). This study evaluates the association of RT dose to CNS structures with patient-reported (PRO) fatigue scores in a population of HNC patients. MATERIALS AND METHODS At pre-RT (baseline), 6th week of RT, and 1-month post-RT time points, Multidimensional Fatigue Inventory (MFI-20) scores were prospectively obtained from 124 patients undergoing definitive treatment for HNC. Medulla, pons, midbrain, total brainstem, cerebellum, posterior fossa, and pituitary dosimetry were evaluated using summary statistics and dose-volume histograms, and associations with MFI-20 scores were analyzed. RESULTS Maximum dose (Dmax) to the brainstem and medulla was significantly associated with MFI-20 scores at 6th week of RT and 1-month post-RT time points, after controlling for baseline scores (p<0.05). Each 1Gy increase in medulla Dmax resulted in an increase in total MFI-20 score over baseline of 0.30 (p=0.026), and 0.25 (p=0.037), at the 6th week of RT and 1-month post-RT, respectively. Each 1Gy increase in brainstem Dmax resulted in an increase in total MFI-20 score over baseline of 0.30 (p=0.027), and 0.25 (p=0.037) at the 6th week of RT, 1-month post-RT, respectively. Statistically significant associations were not found between dosimetry for the other CNS structures and MFI-20 scores. CONCLUSIONS In this analysis of PRO fatigue scores from a population of patients undergoing definitive RT for HNC, maximum dose to the brainstem and medulla was associated with a significantly increased risk of acute patient fatigue.

Simulating the Effect of Spectroscopic MRI as a Metric for Radiation Therapy Planning in Patients with Glioblastoma.

Due to glioblastomas infiltrative nature, an optimal radiation therapy (RT) plan requires targeting infiltration not identified by anatomical magnetic resonance imaging (MRI). Here, high-resolution, whole-brain spectroscopic MRI (sMRI) is used to describe tumor infiltration alongside anatomical MRI and simulate the degree to which it modifies RT target planning. In 11 patients with glioblastoma, data from preRT sMRI scans were processed to give high-resolution, whole-brain metabolite maps normalized by contralateral white matter. Maps depicting choline to N-Acetylaspartate (Cho/NAA) ratios were registered to contrast-enhanced T1-weighted RT planning MRI for each patient. Volumes depicting metabolic abnormalities (1.5-, 1.75-, and 2.0-fold increases in Cho/NAA ratios) were compared with conventional target volumes and contrast-enhancing tumor at recurrence. sMRI-modified RT plans were generated to evaluate target volume coverage and organ-at-risk dose constraints. Conventional clinical target volumes and Cho/NAA abnormalities identified significantly different regions of microscopic infiltration with substantial Cho/NAA abnormalities falling outside of the conventional 60 Gy isodose line (41.1, 22.2, and 12.7 cm3, respectively). Clinical target volumes using Cho/NAA thresholds exhibited significantly higher coverage of contrast enhancement at recurrence on average (92.4%, 90.5%, and 88.6%, respectively) than conventional plans (82.5%). sMRI-based plans targeting tumor infiltration met planning objectives in all cases with no significant change in target coverage. In 2 cases, the sMRI-modified plan exhibited better coverage of contrast-enhancing tumor at recurrence than the original plan. Integration of the high-resolution, whole-brain sMRI into RT planning is feasible, resulting in RT target volumes that can effectively target tumor infiltration while adhering to conventional constraints.

The addition of chemotherapy in the definitive management of high risk prostate cancer

In attempt to improve long-term disease control outcomes for high-risk prostate cancer, numerous clinical trials have tested the addition of chemotherapy (CTX)-either adjuvant or neoadjuvant-to definitive local therapy, either radical prostatectomy (RP) or radiation therapy (RT). Neoadjuvant trials generally confirm safety, feasibility, and pre-RP PSA reduction, but rates of pathologic complete response are rare, and no indications for neoadjuvant CTX have been firmly established. Adjuvant regimens have included CTX alone or in combination with androgen deprivation therapy (ADT). Here we provide a review of the relevant literature, and also quantify utilization of CTX in the definitive management of localized high-risk prostate cancer by querying the National Cancer Data Base. Between 2004 and 2013, 177 patients (of 29,659 total) treated with definitive RT, and 995 (of 367,570 total) treated with RP had CTX incorporated into their treatment regimens. Low numbers of RT + CTX patients precluded further analysis of this population, but we investigated the impact of CTX on overall survival (OS) for patients treated with RP +/- CTX. Disease-free survival or biochemical-recurrence-free survival are not available through the National Cancer Data Base. Propensity-score matching was conducted as patients treated with CTX were a higher-risk group. For nonmatched groups, OS at 5-years was 89.6% for the CTX group vs. 95.6%, for the no-CTX group (P < 0.01). The difference in OS between CTX and no-CTX groups did not persist after propensity-score matching, with 5-year OS 89.6% vs. 90.9%, respectively (Hazard ratio 0.99; P = 0.88). In summary, CTX was not shown to improve OS in this retrospective study. Multimodal regimens-such as RP followed by ADT, RT, and CTX; or RT in conjunction with ADT followed by CTX-have shown promise, but long-term follow-up of randomized data is required.