Demographic differences in the treatment of gastric cancer

e16078

Background: Globally, as of 2020, gastric cancer is the 5th most common cancer and the 4th common cause of cancer-related death. Our objective is to determine how gender/sex, race, treatment location, and socioeconomic factors contribute to the treatment of patients (pts) with gastric cancer. Methods: 233,479 pts were identified from the National Cancer Database (NCDB) between 2004 and 2018. Pts were divided into 3 age-based subgroups. The <=45 y/o (N=14,481) group was designated early-onset gastric cancer (EOGC). The 46 - 70 y/o (N=118,756) group was termed average-onset gastric cancer (AOGC). The >70 y/o (N=100,242) group was termed late-onset gastric cancer (LOGC). Overall 114,117 (48.9%) received surgery; 112,953 (48.4%) received chemotherapy; and 55,024 (23.6%) received radiation therapy. Unfortunately, data were not available on the receipt of bimodal or trimodal therapy. We used chi-square tests and a logistic regression model to examine factors associated with treatment patterns. Factors considered in the model included: age, gender/sex, race/ethnicity, cancer stage, facility type, year of diagnosis, insurance status, and location of residence. Results: Females represented a higher proportion of EOGC pts (47%) compared to AOGC pts (34.5%) and LOGC pts (41%). A greater amount of EOGC pts were Hispanic (24.9%) compared to AOGC pts (10.4%) and LOGC pts (7.1%). EOGC pts were often treated at academic centers (65.8%) compared to AOGC pts (60.9%) and LOGC pts (54.4%). A larger percentage of EOGC pts were uninsured (11.7%) vs AOGC pts (5.4%) and LOGC pts (0.9%). The table outlines differences in treatment by age, sex, race/ethnicity, facility type, year of diagnosis, insurance, and location of residence (after adjusting for stage). Conclusions: EOGC pts display unique demographic characteristics. After adjusting for stage, significant differences exist in how pts with gastric cancer are treated. Further work is needed to delineate the impact of gastric cancer in young pts and determine which factors play a role in treatment for pts of all ages from both the patient and oncologist perspective.[Table: see text]

EA2201: An ECOG-ACRIN phase II study of neoadjuvant nivolumab plus ipilimumab and short course radiation in MSI-H/dMMR rectal tumors

TPS3644

Background: Trimodality therapy including chemoradiation, chemotherapy and surgical resection is standard for patients with T3-4 and/or node-positive (N+) rectal adenocarcinomas. Pathologic complete response (pCR) rates after neoadjuvant chemoradiation approach 15% in all-comers and 27% in patients with microsatellite instability-high (MSI-H) or deficient mismatch repair (dMMR) rectal cancer. Additionally, preclinical data suggest that hypofractionated radiation (large dose per fraction) may enhance immunogenicity. Given high response rates to immunotherapy in MSI-H/dMMR early stage and metastatic colorectal cancer (CRC), we hypothesized that neoadjuvant nivolumab plus ipilimumab and short course radiation in locally advanced MSI-H/dMMR rectal cancer (LARC) would result in increased pCR rates. Methods: EA2201 (NCT04751370) is an NCTN phase II clinical trial for patients with treatment-naïve locally advanced (T3-4Nx or TxN+) rectal adenocarcinoma that is dMMR or MSI-H. Patients receive nivolumab (480 mg) and ipilimumab (1 mg/kg) every 28 days for 2 cycles, followed by short course radiation (5 Gy x 5 fractions; total 25 Gy) and an additional 2 cycles of nivolumab and ipilimumab prior to disease reassessment and TME. The primary endpoint is pCR at TME. Secondary endpoints include 5-year disease-free survival, overall survival, treatment-related toxicities, and sphincter preservation rate for low-lying tumors. This study has a single-arm, two-stage design; a pCR rate of 50% or more will be taken as evidence of promising activity in this patient population. We plan to enroll 31 patients, with accrual currently ongoing. Clinical trial information: NCT04751370.

A phase II/III study of perioperative nivolumab and ipilimumab in patients (pts) with locoregional esophageal (E) and gastroesophageal junction (GEJ) adenocarcinoma: A trial of the ECOG-ACRIN Cancer Research Group (EA2174)

TPS4651

Background: E/GEJ adenocarcinoma has a high mortality rate despite curative intent treatment. A pathologic complete response (pCR) is associated with better overall survival (OS) but occurs in less than 30% of pts. Immunotherapy is effective in the metastatic setting. Here we aim to evaluate the contribution of immunotherapy in the neoadjuvant and adjuvant settings in pts with locoregional E/GEJ cancer. Methods: This is a multi-center, randomized phase II/III trial. Surgical candidates with locoregional E/GEJ adenocarcinoma receive carboplatin AUC 2 IV and paclitaxel 50 mg/m2 IV, both weekly x 5 during concurrent radiation (50.4 Gy) either with or without nivolumab 240 mg IV during weeks 1 and 3, followed by surgery. Pts with no post-operative disease receive nivolumab 240 mg IV every 2 weeks for 12 cycles either with or without ipilimumab 1 mg/kg IV every 6 weeks for 4 cycles. Eligibility criteria include pts with T1-N1-3M0 or T2-3N0-2M0 disease whom are candidates for surgery, no prior chemotherapy or radiation for this disease, no prior immunotherapy, no significant autoimmune disease. Pts must be disease free for adjuvant treatment. Primary neoadjuvant endpoint is pCR rate; primary adjuvant endpoint is disease free survival (DFS). Secondary endpoints include toxicity, DFS and OS. Pre- and mid-treatment diffusion weighted imaging MRI will be conducted during the neoadjuvant portion of the study. A neoadjuvant safety run in of 30 pts is underway. Overall, 278 pts will be needed to detect an absolute improvement of 15% in pCR rate in pts receiving and not receiving neoadjuvant nivolumab and 236 pts will be needed to detect a HR of 0.65 in favor of adjuvant ipilimumab/nivolumab over nivolumab (90% power, one sided alpha of 0.10). Accrual is expected over 34 months at a rate of 8 patients per month. If favorable at interim analysis. Clinical trial information: NCT03604991 .

Combining multiparametric MRI with receptor information to optimize prediction of pathologic response to neoadjuvant therapy in breast cancer: preliminary results

Pathologic complete response following neoadjuvant therapy (NAT) is used as a short-term surrogate marker of eventual outcome in patients with breast cancer. Analyzing voxel-level heterogeneity in MRI-derived parametric maps, obtained before and after the first cycle of NAT ([Formula: see text]), in conjunction with receptor status, may improve the predictive accuracy of tumor response to NAT. Toward that end, we incorporated two MRI-derived parameters, the apparent diffusion coefficient and efflux rate constant, with receptor status in a logistic ridge-regression model. The area under the curve (AUC) and Brier score of the model computed via 10-fold cross validation were 0.94 (95% CI: 0.85, 0.99) and 0.11 (95% CI: 0.06, 0.16), respectively. These two statistics strongly support the hypothesis that our proposed model outperforms the other models that we investigated (namely, models without either receptor information or voxel-level information). The contribution of the receptor information was manifested by an 8% to 15% increase in AUC and a 14% to 21% decrease in Brier score. These data indicate that combining multiparametric MRI with hormone receptor status has a high likelihood of improved prediction of pathologic response to NAT in breast cancer.

Phase IB study of induction chemotherapy with XELOX, followed by radiation therapy, carboplatin, and everolimus in patients with locally advanced esophageal cancer (EC)

e15607

Background: Preclinical studies have shown synergy between everolimus, an mTOR inhibitor, radiation and platinum agents in EC. We conducted a multi-institutional phase IB trial to determine the recommended phase II dose (RP2D) of concurrent everolimus with carboplatin and radiation in non-metastatic EC pts. Methods: Patients with untreated, localized EC and ECOG performance status 0-1 were eligible. Following two cycles of induction Capecitabine/Oxaliplatin (XELOX), pts without evidence of disease progression, received concurrent chemoradiation (total dose: 50.4Gy in 28 fractions), weekly carboplatin (AUC = 2), and escalating doses of everolimus. A standard 3+3 dose escalation design was used. Results: Nineteen patients were enrolled. There were two screen failures (thrombocytopenia, metastases) and 4 pts were removed due to poor tolerance of XELOX (2 pts) or disease progression (2 pts). A total of 13 pts with stage II/III (6/7) EC completed concurrent therapy. Median age 58 (44-71yrs), 85% males; all had adenocarcinoma deemed resectable. One pt at dose level 1 (2.5 mg/QOD), was replaced due to ongoing anxiety. One of 6 pts had a DLT (bowel ischemia). At dose level 2 (2.5mg/QD), 2 out of 6 patients had a DLT (fever with neutropenia and nausea). The RP2D of everolimus was 2.5 mg QOD. Clinically relevant ≥ grade 3 toxicities included lymphopenia (25%), dehydration (12%), fatigue, leukopenia, hyponatremia, abdominal pain, vomiting (each 6%). R0 resection was achieved in 100%; a pathologic response rate (RR) of 40% and a pathologic complete response (pCR) rate of 23% were observed. The 2-year PFS and OS were 50% and 49.6% respectively. Conclusions: The RP2D of everolimus with concurrent weekly carboplatin and radiation is 2.5 mg QOD. Despite the 100% R0 resection rate, the pCR and OS rates were within the expected historical controls. (The study was funded by Novartis Pharmaceuticals) Clinical trial information: NCT01490749.

Abstract P1-10-20: A multi-center trial of intra-operative electronic brachytherapy during breast conservation surgery for early stage breast cancer: Early results of unplanned boost participants

Objective

To assess the safety and efficacy of single-fraction, intra-operative radiation therapy (IORT) delivered as a boost using the Xoft® Axxent® Electronic Brachytherapy System® (eBx®) immediately following surgical resection for treatment of early stage breast cancer.

Methods

This phase 4, open-label, single-arm, prospective, non-randomized trial is still enrolling participants and is currently being conducted at 26 hospitals in the USA (25) and Portugal (1). 878 participants with biopsy-proven ductal carcinoma in situ (DCIS) or invasive ductal carcinoma who met the inclusion criteria underwent lumpectomy followed by single-fraction IORT to the lumpectomy cavity. Briefly, a small, presterilized lead shield piece was placed on the chest wall to reduce the dose to the ribs, and then a balloon applicator, suitable to the surgical bed, was placed in the lumpectomy cavity and inflated with saline (30-75 cc); skin was temporarily closed over the balloon and ultrasound was used to confirm a balloon surface-to-skin distance ≥ 1.0 cm. The Xoft System was used to deliver the 20 Gy dose at the balloon applicator surface. The balloon was deflated, lead shield and balloon removed and the surgical site sutured. Upon the presence of additional risk factors, 37 participants subsequently received whole breast radiation therapy (WBRT); thus, these participants received an unplanned IORT boost and were removed from the primary analysis but will continue to be followed for the duration of the 10-year study. Cosmesis (Harvard Scale) was assessed in this subset of participants. The primary outcome for the main trial is recurrence of ipsilateral breast tumor at 5 years. Trial Registry: ClinicalTrials.gov; Identifier: NCT01644669.

Early Findings

37 boost participants received WBRT (up to 50 Gy) after IORT (36 received the prescribed 20 Gy dose; one received 14 Gy). Mean follow-up time was 430 days (range 13-1119). Mean age at IORT was 62 years (range 45-78). Boost participants had either DCIS (N=5) or invasive ductal carcinoma (N=32). The DCIS nuclear grade was high (N=3), intermediate (N=1), or low (N=1). Invasive cancers were Grade 1 (N=15), 2 (N=10), 3 (N=6), or unknown (N=1). 29 participants had T1, 3 had T2, and 5 had Tis lesions. Mean tumor size was 13.04 ± 10.26 mm. For the two participants who have reached 3-year follow-up, cosmesis was excellent (N=1) and fair (N=1). For the six participants who have reached 2-year follow-up, cosmesis was excellent (N=4), good (N=1), and fair (N=1). There was one serious adverse event with a Grade 3 for skin necrosis. The most frequent side effects were seroma (10%), edema (9%), pain (9%), erythema (6%), and induration (5%). There have been no deaths, recurrences, or new primary tumors among the boost participants to date.

Conclusions

Early results from this multi-center trial suggest that IORT as a tumor-bed boost using the Xoft Axxent eBx System at the time of breast conservation surgery is safe and has low morbidity. To date, the majority of participants receiving an unplanned IORT boost have had excellent to good cosmetic results and the majority of adverse events have been low-grade.

Funding

Funded by Xoft, Inc., a subsidiary of iCAD, Inc.

Citation Format: Syed AMN, Chang H, Schwartzberg B, Bremner A, Boylan S, Lopez-Penalver C, Vito C, Davis M, Dooley W, Chakravarthy AB, Coomer C, Proulx G, Golder S, Ivanov O, Fernandez K, Farha MJ, Gonzalez V, Wengler C, Bhatnagar A, Neuner GA, Kopkash K, Rahman S, Costa P. A multi-center trial of intra-operative electronic brachytherapy during breast conservation surgery for early stage breast cancer: Early results of unplanned boost participants [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-10-20.

Phase I trial of vorinostat added to chemoradiation with capecitabine in pancreatic cancer

BACKGROUND AND PURPOSE

This single institution phase I trial determined the maximum tolerated dose (MTD) of concurrent vorinostat and capecitabine with radiation in non-metastatic pancreatic cancer.

MATERIAL AND METHODS

Twenty-one patients received escalating doses of vorinostat (100-400mg daily) during radiation. Capecitabine was given 1000mg q12 on the days of radiation. Radiation consisted of 30Gy in 10 fractions. Vorinostat dose escalation followed the standard 3+3 design. No dose escalation beyond 400mg vorinostat was planned. Diffusion-weighted (DW)-MRI pre- and post-treatment was used to evaluate in vivo tumor cellularity.

RESULTS

The MTD of vorinostat was 400mg. Dose limiting toxicities occurred in one patient each at dose levels 100mg, 300mg, and 400mg: 2 gastrointestinal toxicities and one thrombocytopenia. The most common adverse events were lymphopenia (76%) and nausea (14%). The apparent diffusion coefficient (ADC) increased in most tumors. Nineteen (90%) patients had stable disease, and two (10%) had progressive disease at time of surgery. Eleven patients underwent surgical exploration with four R0 resections and one R1 resection. Median overall survival was 1.1years (95% confidence interval 0.78-1.35).

CONCLUSIONS

The combination of vorinostat 400mg daily M-F and capecitabine 1000mg q12 M-F with radiation (30Gy in 10 fractions) was well tolerated with encouraging median overall survival.

Association between cytosolic expression of BRCA1 and metastatic risk in breast cancer

Background:

Although BRCA1 has been extensively studied for its role as a tumour-suppressor protein, the role of BRCA1 subcellular localisation in oncogenesis and tumour progression has remained unclear. This study explores the impact of BRCA1 mislocalisation on clinical outcomes in breast cancer.

Methods:

Tissue microarrays assembled from a cohort of patients with all stages of breast cancer were analysed for BRCA1 localisation and correlated with patient survival. Tissue microarrays of patients who had breast cancer that had metastasised to the lung were assembled from an independent cohort of patients. These were analysed for BRCA1 subcellular expression. In vitro studies using cultured human breast cancer cells were conducted to examine the effect of cytosolic BRCA1 on cell migration and efficiency of invasion.

Results:

An inverse association was found between cytosolic BRCA1 expression and metastasis-free survival in patients aged >40 years. Further analysis of BRCA1 subcellular expression in a cohort of breast cancer patients with metastatic disease revealed that the cytosolic BRCA1 content of breast tumours that had metastasised to the lung was 36.0% (95% CI=(31.7%, 40.3%), which was markedly higher than what is reported in the literature (8.2–14.8%). Intriguingly, these lung metastases and their corresponding primary breast tumours demonstrated similarly high cytosolic BRCA1 distributions in both paired and unpaired analyses. Finally, in vitro studies using human breast cancer cells demonstrated that genetically induced BRCA1 cytosolic sequestration (achieved using the cytosol-sequestering BRCA1 5382insC mutation) increased cell invasion efficiency.

Conclusions:

Results from this study suggest a model where BRCA1 cytosolic mislocalisation promotes breast cancer metastasis, making it a potential biomarker of metastatic disease.

53BP1 expression is a modifier of the prognostic value of lymph node ratio and CA 19-9 in pancreatic adenocarcinoma

BACKGROUND

53BP1 binds to the tumor suppressor p53 and has a key role in DNA damage response and repair. Low 53BP1 expression has been associated with decreased survival in breast cancer and has been shown to interact with several prognostic factors in non-small cell lung cancer. The role of 53BP1 in pancreatic ductal adenocarcinoma (PDAC) has yet to be determined. We aimed to investigate whether 53BP1 levels interact with established prognostic factors in PDAC.

METHODS

106 patients for whom there was tissue available at time of surgical resection for PDAC were included. A tissue microarray was constructed using surgical specimens, stained with antibodies to 53BP1, and scored for expression intensity. Univariate and multivariate statistical analyses were performed to investigate the association between 53BP1 and patient survival with known prognostic factors for survival.

RESULTS

The association of 53BP1 with several established prognostic factors was examined, including stage, tumor grade, surgical margin, peripancreatic extension, lymph node ratio (LNR), and CA 19-9. We found that 53BP1 modified the effects of known prognostic variables including LNR and CA 19-9 on survival outcomes. When 53BP1 intensity was low, increased LNR was associated with decreased OS (HR 4.84, 95% CI (2.26, 10.37), p<0.001) and high CA19-9 was associated with decreased OS (HR 1.72, 95% CI (1.18, 2.51), p=0.005). When 53BP1 intensity was high, LNR and CA19-9 were no longer associated with OS (p=0.958 and p=0.606, respectively).

CONCLUSIONS

In this study, 53BP1, a key player in DNA damage response and repair, was found to modify the prognostic value of two established prognostic factors, LNR and CA 19-9, suggesting 53BP1 may alter tumor behavior and ultimately impact how we interpret the value of other prognostic factors.

Phase I trial of chemoradiation with capecitabine and vorinostat in pancreatic cancer

225

Background: Histone deacetylase inhibitors (HDACi) and fluoropyrimidines are synergistic and are radiation (R) sensitizers. The combination of the fluoropyrimidine capecitabine ( C) and the HDACi vorinostat (V) with R was evaluated in the treatment (tx) of non-metastatic pancreatic cancer (NMPC). Methods: Patients (Pts) with NMPC were treated with C + V + R. C dose was 1000 mg q12 Monday (M) - Friday (F) on the days of R. R was given via 3D conformal therapy to a total dose of 3000 cGy in 10 fractions over 2 weeks (wk). V dose was given daily M-F x 4 wk. V doses evaluated were: 100, 200, 300, and 400 mg. Resectability assessment occurred within 6 wk after completion of tx. Diffusion weighted- MRIs (DW-MRIs) were obtained pre tx and one wk after tx initiation to assess tumor cellularity. Peripheral blood mononuclear cells (PBMCs) were collected pre tx, during tx, and after completion to assess whole cell HDAC activity. Unresectable pts could opt for continuation of C and V (CCV) at systemic doses (C 1000 mg q12 x 14 days and V 300 mg QD x 14 days of every 21 day cycle) or come off study. Results: 18 pts were enrolled and evaluable. Disease statuses pre-tx were: resectable (n=1), borderline resectable (n=9), and unresectable (n=8). One DLT occurred at dose levels 1, 3, and 4, 2 GI toxicities and one thrombocytopenia. Most common adverse events were lymphopenia, GI toxicity, and fatigue. On MRI, the apparent diffusion coefficient (ADC) increased in most, but not all, tumors after one wk of tx but did not correlate to change in tumor size at completion. PBMC histone acetylation increased in some pts. Eight pts (Pre-tx status: 1 resectable and 7 borderline resectable) underwent exploration with 4 undergoing tumor resection. No unresectable pt converted to resectable. Four of ten potential pts opted for CCV after being deemed unresectable, 2 with stable disease for 6 cycles. Conclusions: C + V + R is feasible with no unexpected toxicity. HDAC inhibition and ADC decrease on DWI-MRI was seen. Accrual to the final cohort (V 400 mg) is ongoing. This study was approved and funded by the National Comprehensive Cancer Network (NCCN) from general research support provided by Merck & Co., Inc. Study was also supported by the Vanderbilt-Ingram Center Support Grant P30CA68485. Clinical trial information: NCT00983268.

Abstract P4-01-03: quantitative DCE-MRI to predict the response of primary breast cancer to neoadjuvant therapy

The goal of this study was to determine if quantitative changes in dynamic contrast enhanced MRI (DCE-MRI) following a single cycle of chemotherapy can be used to separate pathologic responders (i.e., no residual tumor in the breast at surgery) from pathologic non-responders.

28 patients with Stage II/III breast cancer were enrolled in an IRB-approved clinical trial where breast MRI scans were acquired before (t1) and after one cycle of therapy (t2). Imaging was performed on a 3.0T MR scanner (Philips Healthcare, The Netherlands) and employed a 3D spoiled gradient echo sequence with a spatial resolution of 6.6 mm3 and a temporal resolution of 16 seconds collected at 25 time points before and after the intravenous injection of 0.1 mmol/kg of gadopentetate dimeglumine (Magnevist, Wayne, NJ). At surgery, 12 patients were responders while 16 patients were non-responders.

Both semi-quantitative and quantitative analyses were used to summarize the DCE-MRI data. The semi-quantitative parameters were the signal enhancement rate (SER [1]) and tumor volume (TV). Three pharmacokinetic models, the Tofts-Kety (TK), the Extended Tofts-Kety (ETK), and the fast exchange regime (FXR), were used to estimate the following quantitative parameters: the volume transfer constant (Ktrans), efflux rate constant (kep), vascular volume (vp), and the extravascular extracellular volume fraction (ve) [2]. Each parameter was summarized in two ways: 1) the change in mean from t1 to t2, and 2) the mean at t2. Receiver operating characteristic (ROC) analysis was then performed to determine the ability of each parameter to predict treatment response.

The table displays the areas under the ROC curves (AUC) for each parameter. For the early change in parameters, the AUC for TV and SER were 0.48 and 0.66, respectively. The best AUC of the quantitative parameters was 0.73 from kep estimated by the ETK model. The sensitivities/specificities for TV, SER, and kep for predicting pathologic response were 88%/33%, 64%/79%, and 56%/92%, respectively. For the mean parameter values at t2, the AUCs of TV, SER, and kep were 0.50, 0.56, and 0.79, with sensitivities/specificities for predicting pathologic response of 63%/50%, 93%/21%, and 81%/75%, respectively.

Our results can be interpreted in light of the ACRIN 6657/I-SPY trial [3] which found that change in TV and SER at an early time point were the most predictive of response with AUCs of 0.72 and 0.71, respectively. Our preliminary results, especially our AUC of 0.79 for kep at t2, suggest that a more quantitative analysis of higher temporal resolution DCE-MRI data may achieve comparable or even superior results. Our ongoing efforts involve combining multiple parameters in a multivariate analysis with apparent diffusion coefficient data from diffusion weighted MRI.

An algorithm for longitudinal registration of PET/CT images acquired during neoadjuvant chemotherapy in breast cancer: preliminary results

Background

By providing estimates of tumor glucose metabolism, ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) can potentially characterize the response of breast tumors to treatment. To assess therapy response, serial measurements of FDG-PET parameters (derived from static and/or dynamic images) can be obtained at different time points during the course of treatment. However, most studies track the changes in average parameter values obtained from the whole tumor, thereby discarding all spatial information manifested in tumor heterogeneity. Here, we propose a method whereby serially acquired FDG-PET breast data sets can be spatially co-registered to enable the spatial comparison of parameter maps at the voxel level.

Methods

The goal is to optimally register normal tissues while simultaneously preventing tumor distortion. In order to accomplish this, we constructed a PET support device to enable PET/CT imaging of the breasts of ten patients in the prone position and applied a mutual information-based rigid body registration followed by a non-rigid registration. The non-rigid registration algorithm extended the adaptive bases algorithm (ABA) by incorporating a tumor volume-preserving constraint, which computed the Jacobian determinant over the tumor regions as outlined on the PET/CT images, into the cost function. We tested this approach on ten breast cancer patients undergoing neoadjuvant chemotherapy.

Results

By both qualitative and quantitative evaluation, our constrained algorithm yielded significantly less tumor distortion than the unconstrained algorithm: considering the tumor volume determined from standard uptake value maps, the post-registration median tumor volume changes, and the 25th and 75th quantiles were 3.42% (0%, 13.39%) and 16.93% (9.21%, 49.93%) for the constrained and unconstrained algorithms, respectively (p = 0.002), while the bending energy (a measure of the smoothness of the deformation) was 0.0015 (0.0005, 0.012) and 0.017 (0.005, 0.044), respectively (p = 0.005).

Conclusion

The results indicate that the constrained ABA algorithm can accurately align prone breast FDG-PET images acquired at different time points while keeping the tumor from being substantially compressed or distorted.

Trial registration

NCT00474604

SU11248 (sunitinib) sensitizes pancreatic cancer to the cytotoxic effects of ionizing radiation

PURPOSE

SU11248 (sunitinib) is a small-molecule tyrosine kinase inhibitor which targets VEGFR and PDGFR isoforms. In the present study, the effects of SU11248 and ionizing radiation on pancreatic cancer were studied.

METHODS AND MATERIALS

For in vitro studies human pancreatic adenocarcinoma cells lines were treated with 1 microM SU11248 1 h before irradiation. Western blot analysis was used to determine the effect of SU11248 on radiation-induced signal transduction. To determine if SU11248 sensitized pancreatic cancer to the cytotoxic effects of ionizing radiation, a clonogenic survival assay was performed using 0-6 Gy. For in vivo assays, CAPAN-1 cells were injected into the hind limb of nude mice for tumor volume and proliferation studies.

RESULTS

SU11248 attenuated radiation-induced phosphorylation of Akt and ERK at 0, 5, 15, and 30 min. Furthermore, SU11248 significantly reduced clonogenic survival after treatment with radiation (p < 0.05). In vivo studies revealed that SU11248 and radiation delayed tumor growth by 6 and 10 days, respectively, whereas combined treatment delayed tumor growth by 30 days. Combined treatment with SU11248 and radiation further attenuated Brdu incorporation by 75% (p = 0.001) compared to control.

CONCLUSIONS

SU11248 (sunitinib) sensitized pancreatic cancer to the cytotoxic effects of radiation. This compound is promising for future clinical trials with chemoradiation in pancreatic cancer.

Targeting drug delivery to radiation-induced neoantigens in tumor microvasculature

Radiation can be used to guide drugs to specific sites such as neoplasms or aberrant blood vessels. When blood vessels are treated with ionizing radiation, they respond by expressing a number of cell adhesion molecules and receptors that participate in homeostasis. Examples of radiation-induced molecules in blood vessels include ICAM-1, E-selectin, P-selectin and the beta(3) integrin. We have observed that the endothelium and blood components respond to oxidative stress in a similar, if not identical manner in all tumor models. Although we have identified several other radiation-induced molecules within tumor blood vessels, the beta(3) target for drug delivery achieves the greatest site-specific peptide binding within irradiated tumor blood vessels. We have focused on peptides and antibodies that bind to integrin beta(3). beta(3)-binding proteins have been conjugated to fluorochromes and radionuclides to study the site specificity and microscopic distribution. We have found immunofluorescent and immunohistochemical staining of beta(3) within the lumen of blood vessels immediately following irradiation. To determine whether it is feasible to guide drug delivery to irradiated tumors, we studied ligands to alpha(2b)beta(3) (fibrinogen). Peptides within fibrinogen that bind to alpha(2b)beta(3) includes the dodecapeptide, HHLGGAKQAGDV and the RGD peptide. We utilized 131I conjugation to these ligands to study the biodistribution in tumor bearing mice. Our clinical trial consists of the RGD peptidomimetic, biapcitide, labeled with 99mTc. This study shows that it is feasible to guide drugs to human neoplasms by use of radiation-guided peptides. These studies have shown that peptides that bind to these integrins bind to tumors following exposure to ionizing radiation.