Faculty Bibliography

Purpose: Despite advances in the multimodality care in esophageal cancers, in particular the combination of chemotherapy, radiotherapy and surgery, the 5-year overall survival rate remains only 15-34%. The ability to predict treatment response is therefore of great interest, with the potential to personalize cancer treatment. This project performs a comprehensive texture feature (TF) analysis from esophageal tumor [18F]FDG PET/CT images to establish their predictive value when compared with the PET Response Criteria in Solid Tumors (PERCIST). Methods: Pre/Post chemo-radiation treatment [18F] FDG PET/CT images in sixty five patients were analyzed retrospectively. In all patients, the lesions were identified using nuclear medicine reports. The images were rigid-registered using CERR (a computational environment for clinical research), and segmented using thresholding method. Fifty features, based on the intensity histogram, second and high-order matrices, were extracted from the segmented regions from both image sets. The relative difference of SUVmax and of each TF were used as surrogates for treatment response. One-way ANOVA model of the intra-class correlation coefficient (ICC) and Spearman's rank correlation coefficient (SC) were used to establish correlations between SUVmax and TF treatment response. Results: Relative differences for fifty features were correlated with the corresponding SUVmax based on their ICC values, which were found in the range from 0.4 to 0.6. Two second-order and three high-order feature presented ICC = 0.6 (p < 0.05). Spearman's rank correlation coefficient ranged from -0.7 to 0.7. Two second-order and six high-order features presented 0.5 <= SC <= 0.6 (p < 0.05). Conclusion: Features with high ICC and SC values can be potentially used as additional metrics for treatment assessment. Hence, metabolic texture feature response provides a feasible approach for evaluating clinical outcomes in esophageal chemo-radiation

BACKGROUND & AIMS: The role of radiation therapy in the treatment of patients with pancreatic ductal adenocarcinoma (PDA) is controversial. Randomized controlled trials investigating the efficacy of radiation therapy in patients with locally advanced unresectable PDA have reported mixed results, with effects ranging from modest benefit to worse outcome, compared with control therapies. We investigated whether radiation causes inflammatory cells to acquire an immune-suppressive phenotype that limits the therapeutic effects of radiation on invasive PDAs and accelerates progression of pre-invasive foci. METHODS: We investigated the effects of radiation in p48Cre;LSL-KrasG12D (KC) and p48Cre;LSLKrasG12D;LSL-Trp53R172H (KPC) mice, as well as in C57BL/6 mice with orthotopic tumors grown from FC1242 cells derived from KPC mice. Some mice were given neutralizing antibodies against macrophage colony stimulating factor 1 (CSF1 or MCSF) or F4/80. Pancreata were exposed to doses of radiation ranging from 2-12 Gy and analyzed by flow cytometry. RESULTS: Pancreata of KC mice exposed to radiation had a higher frequency of advanced pancreatic intraepithelial lesions and more foci of invasive cancer than pancreata of unexposed mice (controls); radiation reduced survival time by more than 6 months. A greater proportion of macrophages from invasive and pre-invasive pancreatic tumors had an immune-suppressive, M2-like phenotype, compared with control mice. Pancreata from mice exposed to radiation had fewer CD8+ T cells than controls and greater numbers of CD4+ T cells of T-helper 2 and T-regulatory cell phenotypes. Adoptive transfer of T cells from irradiated PDA to tumors of control mice accelerated tumor growth. Radiation induced production of MCSF by PDA cells. An antibody against MCSF prevented radiation from altering the phenotype of macrophages in tumors, increasing the anti-tumor T-cell response and slowing tumor growth. CONCLUSIONS: Radiation exposure causes macrophages in PDAs of mice to acquire an immune-suppressive phenotype and reduce T-cell mediated anti-tumor responses. Agents that block MCSF prevent this effect, allowing radiation to have increased efficacy in slowing tumor growth.

BACKGROUND: HIV status may affect outcomes after definitive chemoradiotherapy for anal cancer. OBJECTIVE: Here, we report a large series in the highly active antiretroviral therapy era comparing outcomes between HIV-positive and HIV-negative patients with anal cancer. DESIGN: This was a retrospective chart review. SETTINGS: The study was conducted at an outpatient oncology clinic at large academic center. PATIENTS: A total of 107 patients were reviewed, 39 HIV positive and 68 HIV negative. All of the patients underwent definitive chemoradiation for anal cancer. MAIN OUTCOME MEASURES: Data on patient characteristics, treatment, toxicity, and outcomes were collected. Overall survival, colostomy-free survival, local recurrence-free survival, and distant metastasis-free survival were analyzed. RESULTS: Median follow-up was 15 months. HIV-positive patients were younger (median, 52 vs 64 years; p < 0.001) and predominantly men (82% men vs 49% men; p = 0.001). There were no significant differences in T, N, or stage groups. HIV-positive patients had a significantly longer duration from biopsy to start of chemoradiation (mean number of days, 82 vs 54; p = 0.042). There were no differences in rates of acute toxicities including diarrhea, fatigue, or dermatitis. HIV-positive patients had significantly higher rates of hospitalization (33% vs 15%; p = 0.024). The 3-year overall survival rate was 42% in HIV-positive and 76% in HIV-negative patients (p = 0.037; HR, 2.335 (95% CI, 1.032-5.283)). Three-year colostomy-free survival was 67% in HIV-positive and 88% in HIV-negative patients (p = 0.036; HR, 3.231 (95% CI, 1.014-10.299)). Differences in overall survival rates were not significant on multivariate analysis. LIMITATIONS: This study was limited by its retrospective design and small patient numbers. CONCLUSIONS: In this cohort, HIV-positive patients had significantly worse overall and colostomy-free survival rates than HIV-negative patients. However, differences in survival were not significant on multivariate analysis. Additional studies are necessary to establish the etiology of this difference.

OBJECTIVE: To compare clinical and treatment characteristics and outcomes in locally advanced anal cancer, a potentially curable disease, in patients referred from a public or private hospital. METHODS: We retrospectively reviewed 112 anal cancer patients from a public and a private hospital who received definitive chemoradiotherapy at the same cancer center between 2004 and 2013. Tumor stage, radiotherapy delay, radiotherapy duration, and unplanned treatment breaks >/=10 days were compared using t-test and chi(2) test. Overall survival (OS), disease free survival (DFS), and colostomy free survival (CFS) were examined using the Kaplan-Meier method and compared with the log-rank test. Cox proportional hazard models for OS and DFS were developed. RESULTS: The follow-up was 14.9 months (range, 0.7-94.8 months). Public hospital patients presented with significantly higher clinical T stage (P<0.05) and clinical stage group (P<0.05), had significantly longer radiotherapy delays (P<0.05) and radiotherapy duration (P<0.05), and had more frequent radiation therapy (RT) breaks >/=10 days (P<0.05). Three-year OS showed a marked trend in favor of private hospital patients for 3-year OS (72.8% vs. 48.9%; P=0.171), 3-year DFS (66.3% vs. 42.7%, P=0.352), and 3-year CFS (86.4% vs. 68.9%, P=0.299). Referral hospital was not predictive of OS or DFS on multivariate analysis. CONCLUSIONS: Public hospital patients presented at later stage and experienced more delays in initiating and completing radiotherapy, which may contribute to the trend in poorer DFS and OS. These findings emphasize the need for identifying clinical and treatment factors that contribute to decreased survival in low socioeconomic status (SES) populations.

BACKGROUND: Small cell carcinoma of the rectum is a rare neoplasm with scant literature to guide treatment. We used the Surveillance Epidemiology and End Results (SEER) database to investigate the role of radiation therapy in the treatment of this cancer. METHODS: The SEER database (National Cancer Institute) was queried for locoregional cases of small cell rectal cancer. Years of diagnosis were limited to 1988-2010 (most recent available) to reduce variability in staging criteria or longitudinal changes in surgery and radiation techniques. Two month conditional survival was applied to minimize bias by excluding patients who did not survive long enough to receive cancer-directed therapy. Patient demographics between the RT and No_RT groups were compared using Pearson Chi-Square tests. Overall survival was compared between patients who received radiotherapy (RT, n = 43) and those who did not (No_RT, n = 28) using the Kaplan-Meier method. Multivariate Cox proportional hazards model was used to evaluate important covariates. RESULTS: Median survival was significantly longer for patients who received radiation compared to those who were not treated with radiation; 26 mo vs. 8 mo, respectively (log-rank P = 0.009). We also noted a higher 1-year overall survival rate for those who received radiation (71.1% vs. 37.8%). Unadjusted hazard ratio for death (HR) was 0.495 with the use of radiation (95% CI 0.286-0.858). Among surgery, radiotherapy, sex and age at diagnosis, radiation therapy was the only significant factor for overall survival with a multivariate HR for death of 0.393 (95% CI 0.206-0.750, P = 0.005). CONCLUSIONS: Using SEER data, we have identified a significant survival advantage with the use of radiation therapy in the setting of rectal small cell carcinoma. Limitations of the SEER data apply to this study, particularly the lack of information on chemotherapy usage. Our findings strongly support the use of radiation therapy for patients with locoregional small cell rectal cancer.