BACKGROUNDThis phase 2 multi-institutional study was designed to determine whether gemcitabine (GEM) with fractionated stereotactic body radiotherapy (SBRT) results in acceptable late grade 2 to 4 gastrointestinal toxicity when compared with a prior trial of GEM with single-fraction SBRT in patients with locally advanced pancreatic cancer (LAPC).METHODSA total of 49 patients with LAPC received up to 3 doses of GEM (1000 mg/m2) followed by a 1-week break and SBRT (33.0 gray [Gy] in 5 fractions). After SBRT, patients continued to receive GEM until disease progression or toxicity. Toxicity was assessed using the National Cancer Institute Common Terminology Criteria for Adverse Events [version 4.0] and the Radiation Therapy Oncology Group radiation morbidity scoring criteria. Patients completed the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (QLQ-C30) and pancreatic cancer-specific QLQ-PAN26 module before SBRT and at 4 weeks and 4 months after SBRT.RESULTSThe median follow-up was 13.9 months (range, 3.9–45.2 months). The median age of the patients was 67 years and 84% had tumors of the pancreatic head. Rates of acute and late (primary endpoint) grade ≥2 gastritis, fistula, enteritis, or ulcer toxicities were 2% and 11%, respectively. QLQ-C30 global quality of life scores remained stable from baseline to after SBRT (67 at baseline, median change of 0 at both follow-ups; P>.05 for both). Patients reported a significant improvement in pancreatic pain (P =.001) 4 weeks after SBRT on the QLQ-PAN26 questionnaire. The median plasma carbohydrate antigen 19-9 (CA 19-9) level was reduced after SBRT (median time after SBRT, 4.2 weeks; 220 U/mL vs 62 U/mL [P<.001]). The median overall survival was 13.9 months (95% confidence interval, 10.2 months-16.7 months). Freedom from local disease progression at 1 year was 78%. Four patients (8%) underwent margin-negative and lymph node-negative surgical resections.CONCLUSIONSFractionated SBRT with GEM results in minimal acute and late gastrointestinal toxicity. Future studies should incorporate SBRT with more aggressive multiagent chemotherapy.

Background The immune system plays an important role in cancer surveillance and therapy. Chemoradiation can cause severe treatment-related lymphopenia (TRL) (<500 cells/mm3) that is associated with reduced survival. Materials and Methods Data from 4 independent solid tumor studies on serial lymphocyte counts, prognostic factors, treatment, and survival were collected and analyzed. The data set included 297 patients with newly diagnosed malignant glioma (N=96), resected pancreatic cancer (N=53), unresectable pancreatic cancer (N=101), and non–small cell lung cancer (N=47). Results Pretreatment lymphocyte counts were normal in 83% of the patient population, and no patient had severe baseline lymphopenia. Two months after initiating chemoradiation, 43% developed severe and persistent lymphopenia (P=.001). An increased risk for death was attributable to TRL in each cancer cohort (gliomas: hazard rate [HR], 1.8; 95% CI, 1.13–2.87; resected pancreas: HR, 2.2; 95% CI, 1.17–4.12; unresected pancreas: HR, 2.9; 95% CI, 1.53–5.42; and lung: HR, 1.7; 95% CI, 0.8–3.61) and in the entire study population regardless of pathologic findings (HR, 2.1; 95% CI, 1.54–2.78; P<.0001). Severe TRL was observed in more than 40% of patients 2 months after initiating chemoradiation, regardless of histology or chemotherapy regimen, and was independently associated with shorter survival from tumor progression. Conclusions Increased attention and research should be focused on the cause, prevention, and reversal of this unintended consequence of cancer treatment that seems to be related to survival in patients with solid tumors.

Objectives Lymphopenia is a common consequence of chemoradiation therapy yet is seldom addressed clinically. This study was conducted to determine if patients with locally advanced pancreatic cancer (LAPC) treated with definitive chemoradiation develop significant lymphopenia and if this affects clinical outcomes. Methods A retrospective analysis of patients with LAPC treated with chemoradiation at a single institution from 1997 to 2011 was performed. Total lymphocyte counts (TLCs) were recorded at baseline and then monthly during and after chemoradiation. The correlation between treatment-induced lymphopenia, established prognostic factors, and overall survival was analyzed using univariate Cox regression analysis. Important factors identified by univariate analysis were selected as covariates to construct a multivariate proportional hazards model for survival. Results A total of 101 patients met eligibility criteria. TLCs were normal in 86% before chemoradiation. The mean reduction in TLC per patient was 50.6% (SD, 40.6%) 2 months after starting chemoradiation (P< 0.00001), and 46% had TLC< 500 cells/mm3. Patients with TLC < 500 cells/mm3 2 months after starting chemoradiation had inferior median survival (8.7 vs. 13.3mo, P= 0.03) and PFS (4.9 vs. 9.0mo, P = 0.15). Multivariate analysis revealed TLC< 500 cells/mm3 to be an independent predictor of inferior survival (HR= 2.879, P= 0.001) along with baseline serum albumin (HR= 3.584, P = 0.0002), BUN (HR = 1.060, P= 0.02), platelet count (HR= 1.004, P = 0.005), and radiation planning target volume (HR= 1.003, P= 0.0006). Conclusions Severe treatment-related lymphopenia occurs frequently after chemoradiation for LAPC and is an independent predictor of inferior survival.

Purpose Radiation-induced lymphopenia (RIL) is associated with inferior survival in patients with glioblastoma, lung cancer, and pancreatic cancer. We asked whether stereotactic body radiation therapy (SBRT) decreases severity of RIL compared to conventional chemoradiation therapy (CRT) in locally advanced pancreatic cancer (LAPC). Methods and Materials Serial total lymphocyte counts (TLCs) from patients enrolled in a prospective trial of SBRT for LAPC were compared to TLCs from an existing database of LAPC patients undergoing definitive CRT. SBRT patients received 33 Gy (6.6 × Gy 5 fractions). CRT patients received a median dose of 50.4 Gy (1.8 Gy × 28 fractions) with concurrent 5-fluorouracil (77%) or gemcitabine (23%) therapy. Univariate and multivariate analyses (MVA) were used to identify associations between clinical factors and post-treatment TLC and between TLC and survival. Results Thirty-two patients received SBRT and 101 received CRT. Median planning target volume (PTV) was smaller in SBRT (88.7 cm3) than in CRT (344.6 cm3; P<.001); median tumor diameter was larger for SBRT (4.6 cm) than for CRT (3.6 cm; P=.01). SBRT and CRT groups had similar median baseline TLCs. One month after starting radiation, 71.7% of CRT patients had severe lymphopenia (ie, TLC <500 cells/mm3 vs 13.8% of SBRT patients; P<.001). At 2 months, 46.0% of CRT patients remained severely lymphopenic compared with 13.6% of SBRT patients (P=.007). MVA demonstrated that treatment technique and baseline TLCs were significantly associated with post-treatment TLC at 1 but not 2 months after treatment. Higher post-treatment TLC was associated with improved survival regardless of treatment technique (hazard ratio [HR] for death: 2.059; 95% confidence interval: 1.310–3.237; P=.002). Conclusions SBRT is associated with significantly less severe RIL than CRT at 1 month in LAPC, suggesting that radiation technique affects RIL and supporting previous modeling studies. Given the association of severe RIL with survival in LAPC, further study of the effect of radiation technique on immune status is warranted.

Mutational inactivation of ATRX (α-thalassemia mental retardation X-linked) represents a defining molecular alteration in large subsets of malignant glioma. Yet the pathogenic consequences of ATRX deficiency remain unclear, as do tractable mechanisms for its therapeutic targeting. Here we report that ATRX loss in isogenic glioma model systems induces replication stress and DNA damage by way of G-quadruplex (G4) DNA secondary structure. Moreover, these effects are associated with the acquisition of disease-relevant copy number alterations over time. We then demonstrate, both in vitro and in vivo, that ATRX deficiency selectively enhances DNA damage and cell death following chemical G4 stabilization. Finally, we show that G4 stabilization synergizes with other DNA-damaging therapies, including ionizing radiation, in the ATRX-deficient context. Our findings reveal novel pathogenic mechanisms driven by ATRX deficiency in glioma, while also pointing to tangible strategies for drug development.

Purpose TNFerade biologic is a novel means of delivering tumor necrosis factor alpha to tumor cells by gene transfer. We herein report final results of the largest randomized phase III trial performed to date among patients with locally advanced pancreatic cancer (LAPC) and the first to test gene transfer against this malignancy. Patients and Methods In all, 304 patients were randomly assigned 2:1 to standard of care plus TNFerade (SOC + TNFerade) versus standard of care alone (SOC). SOC consisted of 50.4 Gy in 28 fractions with concurrent fluorouracil (200 mg/m2 per day continuous infusion). TNFerade was injected intratumorally before the first fraction of radiotherapy each week at a dose of 4 × 1011 particle units by using either a percutaneous transabdominal or an endoscopic ultrasound approach. Four weeks after chemoradiotherapy, patients began gemcitabine (1,000 mg/m2 intravenously) with or without erlotinib (100 to 150 mg per day orally) until progression or toxicity. Results The analysis included 187 patients randomly assigned to SOC + TNFerade and 90 to SOC by using a modified intention-to-treat approach. Median follow-up was 9.1 months (range, 0.1 to 50.5 months). Median survival was 10.0 months for patients in both the SOC + TNFerade and SOC arms (hazard ratio [HR], 0.90; 95% CI, 0.66 to 1.22; P = .26). Median progression-free survival (PFS) was 6.8 months for SOC + TNFerade versus 7.0 months for SOC (HR, 0.96; 95% CI, 0.69 to 1.32; P = .51). Among patients treated on the SOC + TNFerade arm, multivariate analysis showed that TNFerade injection by an endoscopic ultrasound-guided transgastric/transduodenal approach rather than a percutaneous transabdominal approach was a risk factor for inferior PFS (HR, 2.08; 95% CI, 1.06 to 4.06; P = .032). The patients in the SOC + TNFerade arm experienced more grade 1 to 2 fever and chills than those in the SOC arm (P < .001) but both arms had similar rates of grade 3 to 4 toxicities (all P > .05). Conclusion SOC + TNFerade is safe but not effective for prolonging survival in patients with LAPC.

Background EUS-guided fiducial placement facilitates image-guided radiation therapy (IGRT). Objective To compare 2 types of commercially available fiducials for technical success, complications, visibility, and migration. Design Retrospective, single-center, comparative study. Setting Tertiary-care medical center. Interventions Traditional fiducials (TFs) (5-mm length, 0.8-mm diameter) and Visicoil fiducials (VFs) (10-mm length, 0.35-mm diameter) were compared. Fiducials were placed using linear 19-gauge (for TFs) or 22-gauge (for VFs) needles. A subjective visualization scoring system (0-2; 0 = not visible, 1 = barely visible, 2 = clearly visible) was used to assess visibility on CT. Fiducial migration was calculated as a change in interfiducial distance. Main Outcome Measurements Technical success, complications, visibility, and migration of 2 types of fiducials. Results Thirty-nine patients with locally advanced pancreatic cancer underwent EUS-guided placement of 103 fiducials (77 TFs, 26 VFs). The mean number of fiducials placed per patient was 2.66 (standard deviation 0.67) for the 19-gauge needle and 2.60 (standard deviation 0.70) for the 22-gauge needle (P = .83). No intra- or postprocedural complications were encountered. The median visibility score for TFs was significantly better than that for VFs, both when scores of 0 were and were not included (2.00, interquartile range [IQR] 2.00-2.00 vs 1.75, IQR 1.50-2.00, P = .009 and 2.00, IQR 2.00-2.00 vs 2.00, IQR 1.50-2.00, P < .0001, respectively). The mean migration was not significantly different between the 2 types of fiducials (0.8 mm [IQR 0.4-1.6 mm] for TFs vs 1.3 mm [IQR 0.6-1.5 mm] for VFs; P = .72). Limitations Retrospective, nonrandomized design. Conclusions Visibility was significantly better for TFs compared with VFs. The degree of fiducial migration was not significantly different for TFs and VFs. There was no significant difference in the mean number of fiducials placed, indicating a similar degree of technical difficulty for TF and VF deployment.

Twist1, a basic helix-loop-helix transcription factor, plays a key role during development and is a master regulator of the epithelial-mesenchymal transition (EMT) that promotes cancer metastasis. Structure-function relationships of Twist1 to cancer-related phenotypes are underappreciated, so we studied the requirement of the conserved Twist box domain for metastatic phenotypes in prostate cancer (PCa). Evidence suggests that Twist1 is overexpressed in clinical specimens and correlated with aggressive/metastatic disease. Therefore, we examined a transactivation mutant, Twist1-F191G, in PCa cells using in vitro assays which mimic various stages of metastasis. Twist1 overexpression led to elevated cytoskeletal stiffness and cell traction forces at the migratory edge of cells based on biophysical single-cell measurements. Twist1 conferred additional cellular properties associated with cancer cell metastasis including increased migration, invasion, anoikis resistance, and anchorage-independent growth. The Twist box mutant was defective for these Twist1 phenotypes in vitro. Importantly, we observed a high frequency of Twist1-induced metastatic lung tumors and extra-thoracic metastases in vivo using the experimental lung metastasis assay. The Twist box was required for PCa cells to colonize metastatic lung lesions and extra-thoracic metastases. Comparative genomic profiling revealed transcriptional programs directed by the Twist box that were associated with cancer progression, such as Hoxa9. Mechanistically, Twist1 bound to the Hoxa9 promoter and positively regulated Hoxa9 expression in PCa cells. Finally, Hoxa9 was important for Twist1-induced cellular phenotypes associated with metastasis. These data suggest that the Twist box domain is required for Twist1 transcriptional programs and PCa metastasis.