Jingsheng Yan

Phase I Dose-Escalation Study of Stereotactic Body Radiation Therapy for Low- and Intermediate-Risk Prostate Cancer

PURPOSE To evaluate the tolerability of escalating doses of stereotactic body radiation therapy in the treatment of localized prostate cancer. PATIENTS AND METHODS Eligible patients included those with Gleason score 2 to 6 with prostate-specific antigen (PSA) ≤ 20, Gleason score 7 with PSA ≤ 15, ≤ T2b, prostate size ≤ 60 cm(3), and American Urological Association (AUA) score ≤ 15. Pretreatment preparation required an enema and placement of a rectal balloon. Dose-limiting toxicity (DLT) was defined as grade 3 or worse GI/genitourinary (GU) toxicity by Common Terminology Criteria of Adverse Events (version 3). Patients completed quality-of-life questionnaires at defined intervals. RESULTS Groups of 15 patients received 45 Gy, 47.5 Gy, and 50 Gy in five fractions (45 total patients). The median follow-up is 30 months (range, 3 to 36 months), 18 months (range, 0 to 30 months), and 12 months (range, 3 to 18 months) for the 45 Gy, 47.5 Gy, and 50 Gy groups, respectively. For all patients, GI grade ≥ 2 and grade ≥ 3 toxicity occurred in 18% and 2%, respectively, and GU grade ≥ 2 and grade ≥ 3 toxicity occurred in 31% and 4%, respectively. Mean AUA scores increased significantly from baseline in the 47.5-Gy dose level (P = .002) as compared with the other dose levels, where mean values returned to baseline. Rectal quality-of-life scores (Expanded Prostate Cancer Index Composite) fell from baseline up to 12 months but trended back at 18 months. In all patients, PSA control is 100% by the nadir + 2 ng/mL failure definition. CONCLUSION Dose escalation to 50 Gy has been completed without DLT. A multicenter phase II trial is underway treating patients to 50 Gy in five fractions to further evaluate this experimental therapy.

Inhibition of DNA Double-Strand Break Repair by the Dual PI3K/mTOR Inhibitor NVP-BEZ235 as a Strategy for Radiosensitization of Glioblastoma

Purpose: Inhibitors of the DNA damage response (DDR) have great potential for radiosensitization of numerous cancers, including glioblastomas, which are extremely radio- and chemoresistant brain tumors. Currently, there are no DNA double-strand break (DSB) repair inhibitors that have been successful in treating glioblastoma. Our laboratory previously demonstrated that the dual phosphoinositide 3-kinase/mTOR inhibitor NVP-BEZ235 can potently inhibit the two central DDR kinases, DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and ataxia-telangiectasia mutated (ATM), in vitro. Here, we tested whether NVP-BEZ235 could also inhibit ATM and DNA-PKcs in tumors in vivo and assessed its potential as a radio- and chemosensitizer in preclinical mouse glioblastoma models. Experimental Design: The radiosensitizing effect of NVP-BEZ235 was tested by following tumor growth in subcutaneous and orthotopic glioblastoma models. Tumors were generated using the radioresistant U87-vIII glioma cell line and GBM9 neurospheres in nude mice. These tumors were then treated with ionizing radiation and/or NVP-BEZ235 and analyzed for DNA-PKcs and ATM activation, DSB repair inhibition, and attenuation of growth. Results: NVP-BEZ235 potently inhibited both DNA-PKcs and ATM kinases and attenuated the repair of ionizing radiation–induced DNA damage in tumors. This resulted in striking tumor radiosensitization, which extended the survival of brain tumor–bearing mice. Notably, tumors displayed a higher DSB-load when compared with normal brain tissue. NVP-BEZ235 also sensitized a subset of subcutaneous tumors to temozolomide, a drug routinely used concurrently with ionizing radiation for the treatment of glioblastoma. Conclusions: These results demonstrate that it may be possible to significantly improve glioblastoma therapy by combining ionizing radiation with potent and bioavailable DNA repair inhibitors such as NVP-BEZ235. Clin Cancer Res; 20(5); 1235–48. ©2013 AACR.

Modulating Endogenous NQO1 Levels Identifies Key Regulatory Mechanisms of Action of β-Lapachone for Pancreatic Cancer Therapy

Purpose: Pancreatic cancer is the fourth leading cause of cancer-related deaths, in which the 5-year survival rate is less than 5%. Current standard of care therapies offer little selectivity and high toxicity. Novel, tumor-selective approaches are desperately needed. Although prior work suggested that β-lapachone (β-lap) could be used for the treatment of pancreatic cancers, the lack of knowledge of the compounds mechanism of action prevented optimal use of this agent. Experimental Design: We examined the role of NAD(P)H:quinone oxidoreductase-1 (NQO1) in β-lap–mediated antitumor activity, using a series of MIA PaCa-2 pancreatic cancer clones varying in NQO1 levels by stable shRNA knockdown. The antitumor efficacy of β-lap was determined using an optimal hydroxypropyl-β-cyclodextran (HPβ-CD) vehicle formulation in metastatic pancreatic cancer models. Results: β-Lap–mediated cell death required ∼90 enzymatic units of NQO1. Essential downstream mediators of lethality were as follows: (i) reactive oxygen species (ROS); (ii) single-strand DNA breaks induced by ROS; (iii) poly(ADP-ribose)polymerase-1 (PARP1) hyperactivation; (iv) dramatic NAD+/ATP depletion; and (v) programmed necrosis. We showed that 1 regimen of β-lap therapy (5 treatments every other day) efficaciously regressed and reduced human pancreatic tumor burden and dramatically extended the survival of athymic mice, using metastatic pancreatic cancer models. Conclusions: Because NQO1 enzyme activities are easily measured and commonly overexpressed (i.e., >70%) in pancreatic cancers 5- to 10-fold above normal tissue, strategies using β-lap to efficaciously treat pancreatic cancers are indicated. On the basis of optimal drug formulation and efficacious antitumor efficacy, such a therapy should be extremely safe and not accompanied with normal tissue toxicity or hemolytic anemia. Clin Cancer Res; 17(2); 275–85. ©2011 AACR.

A multicenter phase II study of cisplatin, pemetrexed, and bevacizumab in patients with advanced malignant mesothelioma.

INTRODUCTION Malignant mesothelioma (MM) cells express the vascular endothelial growth factor (VEGF) receptor, and VEGF protein expression is detected in a majority of human mesothelioma biopsy specimens. Bevacizumab is a recombinant humanized monoclonal antibody that blocks the binding of VEGF to its receptor. We evaluated the addition of bevacizumab to cisplatin and pemetrexed as first-line treatment in patients with advanced, unresectable MM. METHODS Previously untreated MM patients with advanced, unresectable disease received cisplatin (75 mg/m(2)), pemetrexed (500 mg/m(2)), and bevacizumab (15 mg/kg) intravenously every 21 days for a maximum of 6 cycles. Patients with responsive or stable disease received bevacizumab (15 mg/kg) intravenously every 21 days until progression or intolerance. The primary endpoint was progression-free survival rate at 6 months. RESULTS 53 patients were enrolled at 4 centers; 52 were evaluable for this analysis. The progression-free survival rate at 6 months was 56% and the median progression-free survival was 6.9 months (95% confidence interval [CI], 5.3-7.8 months). The partial response rate was 40% and 35% of patients had stable disease. Median overall survival was 14.8 months (95% CI; 10.0-17.0 months). Grade 3/4 toxicities included neutropenia in 11%, hypertension in 6%, and venous thromboembolism in 13% of patients. CONCLUSION This trial evaluating the addition of bevacizumab to cisplatin and pemetrexed in patients with previously untreated, advanced MM failed to meet the primary endpoint of a 33% improvement in the progression-free survival rate at 6 months compared with historical controls treated with cisplatin and pemetrexed alone.

Lung Cancer Diagnostic and Treatment Intervals in the United States: A Health Care Disparity?

Introduction: Lung cancer diagnostic and treatment delays have been described for several patient populations. However, few studies have analyzed these intervals among patients treated in contemporary health care systems in the United States. We therefore studied the timing of lung cancer diagnosis and treatment at a U.S. medical center providing care to a diverse patient population within two different hospital systems. Methods: We performed a retrospective analysis of consecutive patients diagnosed with non-small cell lung cancer stage I to III from 2000 to 2005 at public and private hospitals affiliated with the University of Texas Southwestern Medical Center. We recorded patient and disease characteristics; dates of initial radiograph suspicious for lung cancer, diagnosis, and treatment; and overall survival. Associations between these factors were assessed using univariate analysis, multivariate logistic regression, and Kaplan-Meier survival analysis. Results: A total of 482 patients met criteria for analysis. In univariate analyses, the image-treatment interval was significantly associated with race, age, income, insurance type, and hospital type (76 days for public versus 45 days for private; p < 0.0001). In multivariate analysis, only hospital type remained significantly associated with the image-treatment interval; patients in the private hospital setting were more likely to receive timely treatment (hazard ratio 1.85; 95% confidence interval, 1.37–2.50; p < 0.001). In univariate analysis, the image-treatment interval was not associated with disease stage (p = 0.27) or with survival (p = 0.42). Conclusion: Intervals between suspicion, diagnosis, and treatment of lung cancer vary widely among patients. Health care system factors, such as hospital type, largely account for these discrepancies. In this study, these intervals do not appear to be associated with clinical outcomes.

Prostate Cancer Radiosensitization through Poly(ADP-Ribose) Polymerase-1 Hyperactivation

The clinical experimental agent, β-lapachone (β-lap; Arq 501), can act as a potent radiosensitizer in vitro through an unknown mechanism. In this study, we analyzed the mechanism to determine whether β-lap may warrant clinical evaluation as a radiosensitizer. β-Lap killed prostate cancer cells by NAD(P)H:quinone oxidoreductase 1 (NQO1) metabolic bioactivation, triggering a massive induction of reactive oxygen species, irreversible DNA single-strand breaks (SSB), poly(ADP-ribose) polymerase-1 (PARP-1) hyperactivation, NAD(+)/ATP depletion, and μ-calpain-induced programmed necrosis. In combination with ionizing radiation (IR), β-lap radiosensitized NQO1(+) prostate cancer cells under conditions where nontoxic doses of either agent alone achieved threshold levels of SSBs required for hyperactivation of PARP-1. Combination therapy significantly elevated SSB level, γ-H2AX foci formation, and poly(ADP-ribosylation) of PARP-1, which were associated with ATP loss and induction of μ-calpain-induced programmed cell death. Radiosensitization by β-lap was blocked by the NQO1 inhibitor dicoumarol or the PARP-1 inhibitor DPQ. In a mouse xenograft model of prostate cancer, β-lap synergized with IR to promote antitumor efficacy. NQO1 levels were elevated in ∼60% of human prostate tumors evaluated relative to adjacent normal tissue, where β-lap might be efficacious alone or in combination with radiation. Our findings offer a rationale for the clinical utilization of β-lap (Arq 501) as a radiosensitizer in prostate cancers that overexpress NQO1, offering a potentially synergistic targeting strategy to exploit PARP-1 hyperactivation.

Looking beyond surveillance, epidemiology, and end results: patterns of chemotherapy administration for advanced non-small cell lung cancer in a contemporary, diverse population.

Introduction: Chemotherapy prolongs survival without substantially impairing quality of life for medically fit patients with advanced non-small cell lung cancer (NSCLC), but population-based studies have shown that only 20 to 30% of these patients receive chemotherapy. These earlier studies have relied on Medicare-linked Surveillance, Epidemiology, and End Results (SEER) data, thus excluding the 30 to 35% of lung cancer patients younger than 65 years. Therefore, we determined the use of chemotherapy in a contemporary, diverse NSCLC population encompassing all patient ages. Methods: We performed a retrospective analysis of patients diagnosed with stage IV NSCLC from 2000 to 2007 at the University of Texas Southwestern Medical Center. Demographic, treatment, and outcome data were obtained from hospital tumor registries. The association between these variables was assessed using univariate analysis and multivariate logistic regression. Results: In all, 718 patients met criteria for analysis. Mean age was 60 years, 58% were men, and 45% were white. Three hundred fifty-three patients (49%) received chemotherapy. In univariate analysis, receipt of chemotherapy was associated with age (53% of patients younger than 65 years versus 41% of patients aged 65 years and older; p = 0.003) and insurance type (p < 0.001). In a multivariate model, age and insurance type remained associated with receipt of chemotherapy. For individuals receiving chemotherapy, median survival was 9.2 months, compared with 2.3 months for untreated patients (p < 0.001). Conclusions: In a contemporary population representing the full age range of patients with advanced NSCLC, chemotherapy was administered to approximately half of all patients—more than twice the rate reported in some earlier studies. Patient age and insurance type are associated with receipt of chemotherapy.

Predictors and impact of second-line chemotherapy for advanced non-small cell lung cancer in the United States: real-world considerations for maintenance therapy.

Introduction: Recent clinical trials incorporating maintenance chemotherapy into the initial treatment of advanced non-small cell lung cancer (NSCLC) have highlighted the benefits of exposing patients to second-line therapies. We, therefore, determined the predictors and impact of second-line chemotherapy administration in a contemporary, diverse NSCLC population. Methods: We performed a retrospective analysis of consecutive patients diagnosed with stage IV NSCLC from 2000 to 2007 at clinical facilities associated with the University of Texas Southwestern Medical Center. Demographic, disease, treatment, and outcome data were obtained from hospital tumor registries. The association between these variables was assessed using univariate analysis and multivariate logistic regression. Results: A total of 406 patients in this cohort received first-line chemotherapy and were included in the analysis. Mean age was 59 years, 28% were women, and 59% were white. Among these patients, 197 (49%) received second-line chemotherapy. Among those patients who had not progressed after four to six cycles of first-line chemotherapy, 67% received second-line chemotherapy. Receipt of second-line chemotherapy was significantly associated with patient insurance type (p = 0.007), number of cycles of first-line chemotherapy (p < 0.001), and receipt of prechemotherapy palliative radiation therapy (p = 0.005) but was not associated with patient age, gender, race, histology, or year of diagnosis. In a multivariate model, second-line chemotherapy administration remained associated with insurance type (p = 0.003), number of cycles of first-line chemotherapy (p < 0.001), and receipt of prechemotherapy palliative radiation therapy (p = 0.008). The number of cycles of first-line chemotherapy and administration of second-line chemotherapy were associated with overall survival in both univariate and multivariate analyses. Conclusions: In this unselected, contemporary, and diverse cohort of patients with advanced NSCLC, 67% of individuals whose disease had not progressed after four to six cycles of first-line chemotherapy eventually received second-line chemotherapy. Markers of socioeconomic status, symptom burden, and response to and tolerance of first-line chemotherapy were associated with receipt of second-line chemotherapy. These factors may assist in the selection of patients most likely to benefit from maintenance chemotherapy.

Predictors and intensity of online access to electronic medical records among patients with cancer.

INTRODUCTION Electronic portals are secure Web-based servers that provide patients with real-time access to their personal health record (PHR). These applications are now widely used at cancer centers nationwide, but their impact has not been well studied. This study set out to determine predictors and patterns of use of a Web-based portal for accessing PHRs and communicating with health providers among patients with cancer. METHODS Retrospective analysis of enrollment in and use of MyChart, a PHR portal for the Epic electronic medical record system, among patients seen at a National Cancer Institute-designated cancer center. Predictors of MyChart use were analyzed through univariable and multivariable regression models. RESULTS A total of 6,495 patients enrolled in MyChart from 2007 to 2012. The median number of log-ins over this period was 57 (interquartile range 17-137). The most common portal actions were viewing test results (37%), viewing and responding to clinic messages (29%), and sending medical advice requests (6.4%). Increased portal use was significantly associated with younger age, white race, and an upper aerodigestive malignancy diagnosis. Thirty-seven percent of all log-ins and 31% of all medical advice requests occurred outside clinic hours. Over the study period, the average number of patient log-ins per year more than doubled. CONCLUSIONS Among patients with cancer, PHR portal use is frequent and increasing. Younger patients, white patients, and patients with upper aerodigestive malignancies exhibit the heaviest portal use. Understanding the implications of this new technology will be central to the delivery of safe and effective care.

Influence of Surgical Technique on Mastectomy and Reexcision Rates in Breast-Conserving Therapy for Cancer

Introduction. Breast conserving surgery (BCS) requires tumor excision with negative margins. Reexcision rates of 30–50% are reported. Ultrasound localization, intraoperative margin pathology, and specimen mammography have reduced reexcisions, but require new equipment. Cavity shave margin (CSM) is a technique, utilizing existing equipment, that potentially reduces reexcision. This study evaluates CSM reexcision impact. Methods. 522 cancers treated with BCS were reviewed. Patients underwent standard partial mastectomy (SPM) or CSM. Data collected included demographics, pathology, and treatments. Results. 455 SPMs were compared to 67 CSMs. Analysis revealed no differences in pathology, intraductal component, or neoadjuvant chemotherapy. Overall reexcision rate = 43%. Most reexcisions were performed for DCIS at margin. SPMs underwent 213 reexcisions (46.8%), versus 16/67 (23.9%) CSMs (P = 0.0003). Total mastectomy as definitive procedure was performed after more SPMs (P = 0.009). Multivariate analysis revealed CSM, % DCIS, tumor size, and race to influence reexcisions. Conclusions. CSM is a technique that reduces reexcisions and mastectomy rates.