Optimal breast cancer risk reduction policies tailored to personal risk level.

Depending on personal and hereditary factors, each woman has a different risk of developing breast cancer, one of the leading causes of death for women. For women with a high-risk of breast cancer, their risk can be reduced by two main therapeutic approaches: 1) preventive treatments such as hormonal therapies (i.e., tamoxifen, raloxifene, exemestane); or 2) a risk reduction surgery (i.e., mastectomy). Existing national clinical guidelines either fail to incorporate or have limited use of the personal risk of developing breast cancer in their proposed risk reduction strategies. As a result, they do not provide enough resolution on the benefit-risk trade-off of an intervention policy as personal risk changes. In addressing this problem, we develop a discrete-time, finite-horizon Markov decision process (MDP) model with the objective of maximizing the patient's total expected quality-adjusted life years. We find several useful insights some of which contradict the existing national breast cancer risk reduction recommendations. For example, we find that mastectomy is the optimal choice for the border-line high-risk women who are between ages 22 and 38. Additionally, in contrast to the National Comprehensive Cancer Network recommendations, we find that exemestane is a plausible, in fact, the best, option for high-risk postmenopausal women.

Phase 1b study of orteronel in postmenopausal women with hormone-receptor positive (HR+) metastatic breast cancer.

Introduction Suppressing both androgens and estrogens may circumvent hormone receptor resistance in breast cancer by reducing androgen receptor stimulation. Selective inhibition of the 17, 20-lyase enzyme by orteronel leads to decreased androgen production in men and would be anticipated to reduce estrogen and androgen production in women. Thus, we conducted a phase 1b study of orteronel in postmenopausal women with hormone-receptor positive (HR+) metastatic breast cancer. Methods The primary objective was to identify the recommended phase 2 dose (R2PD) of orteronel in women; escalation was via standard 3 + 3 design. The initial dose was 300 mg BID and escalated to 400 mg BID. Cycle length was 28 days. Enrolled patients had HR+ metastatic breast cancer and were evaluated every 8 weeks for disease progression. Results Eight heavily pre-treated women enrolled [median age: 57 yo (range 47-73)]. Four received 300 mg BID at dose level 1; 4 received 400 mg BID at dose level 2. No dose limiting toxicities (DLTs) were observed. Adverse events (AE) at least possibly related to orteronel included grade 1-2 nausea (n = 4) and bone pain (n = 3), and grade 1 hypokalemia, hot flashes, myalgia and AST elevation (n = 2). The only grade 3 AE was hypertension (n = 2) with 8 patients receiving 34 cycles of treatment. No objective responses were seen; clinical benefit was seen in 2 patients with stable disease for more than 6 months. Serum estrogens and testosterone were suppressed from baseline on both doses of orteronel. Conclusions Orteronel 400 mg BID is well tolerated in postmenopausal women, and significantly suppresses serum estrogens and testosterone. Clinical benefit was seen among heavily pretreated postmenopausal women with HR+ metastatic breast cancer.

Role of the androgen receptor in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is an aggressive disease with outcomes inferior to those of other breast cancer subtypes. No targeted therapies are currently approved for TNBC, and newer treatment approaches are critically needed. It is increasingly recognized that TNBC is a heterogeneous disease, and the role of androgen signaling in a subset of TNBC is emerging. Although the degree of androgen receptor (AR) expression in TNBC varies widely depending on the assay methodology, cutoff for positivity, and patient population, existing evidence suggests an association between a higher level of AR expression and improved outcomes. Despite lower pathologic complete response (pCR) rates with neoadjuvant therapy, patients with AR-dependent TNBCs have a better prognosis than those with TNBCs that are not AR-dependent. Furthermore, gene expression profiling has been used to identify a luminal androgen receptor subtype of TNBC that is dependent on AR signaling. Early clinical studies investigating agents targeting AR in advanced TNBC have produced promising results. We review herein the literature on the biology of AR in breast cancer and its prognostic and predictive role in TNBC, and we describe the results of early clinical trials with antiandrogens in this population. We also present our vision of the future development of newer therapeutic strategies in AR-dependent TNBC.

Final analysis of a phase II trial of daratumumab, carfilzomib, lenalidomide, and dexamethasone in newly diagnosed multiple myeloma without transplant.

We evaluated the efficacy and safety of 24 cycles of Dara in combination with carfilzomib (K), lenalidomide (R), and dexamethasone (d) without autologous stem cell transplant (ASCT) in newly diagnosed multiple myeloma (NDMM) irrespective of ASCT eligibility in a single-arm, phase II study. The primary endpoint was the rate of stringent complete response (sCR) and/or measurable residual disease (MRD) < 10-5 by next-generation sequencing (NGS) at the end of cycle 8 (C8). MRD was also assessed on peripheral blood samples using both the EXENT® system and liquid chromatography-mass spectrometry (LC-MS). Forty-two patients entered the treatment phase; forty were evaluable for the primary endpoint. The rate of sCR and/or MRD < 10-5 following C8 was 30/40 (75%), meeting the statistical threshold for efficacy. The 10-6 MRD negative rate improved with treatment beyond C8. Agreement between EXENT® and NGS was high and increased over time; agreement between LC-MS and NGS was lower. The estimated 3-year progression-free survival progression-free survival was 85%, and 3-year overall survival was 95%. Upper respiratory infections occurred in 67% (7% grade 3-4). There were no treatment-related deaths. Extended frontline Dara-KRd induced a high rate of sCR and/or MRD negativity; the rate and depth of MRD negativity improved beyond C8.

SWOG/NCI Phase II Dual Anti-CTLA-4/PD-1 Blockade in Rare Tumors (DART): Non-Epithelial Ovarian Cancer.

BACKGROUND: The role of dual checkpoint inhibition in advanced rare/ultra-rare non-epithelial ovarian cancers (NEOCs) is yet to be explored. METHODS: DART is a prospective, multicenter (1,016 US sites), multi-cohort, single-arm phase II trial conducted through the Early Therapeutics and Rare Cancer SWOG/NCI Committee, assessing ipilimumab (anti-CTLA-4) (1mg/kg every 6 weeks) and nivolumab (anti-PD-1) (240mg every 2 weeks) in adults with advanced NEOCs who lack beneficial standard therapy. Primary outcome was overall response rate [ORR; complete response (CR)/partial response (PR)]; secondary outcomes were progression-free survival (PFS), overall survival (OS), clinical benefit rate [CBR; stable disease (SD) ≥6 months plus ORR], and toxicity. RESULTS: Seventeen patients (median age: 64; number of prior therapies ranged from 0-8 with no immunotherapy exposure; 8 granulosa, 6 carcinosarcomas, 1 Sertoli-Leydig, 1 yolk sac, 1 Wolffian) were evaluated. In granulosa cell tumors, ORR was 25% (n=2/8; 1 CR, 1 PR) and CBR, 50% (n=4/8); PFS of 58.3 (CR), 50.7+ (PR), 30.4 (SD), and 8.7 (SD) months. Median PFS was 3.5 months (95% confidence intervals (CI) 1.7-11.2 months); median OS, 42.5 months (95% CI 10.1 months-not reached). One Sertoli-Leydig cell tumor showed a 22% regression (PFS 11.2 months). Carcinosarcomas had no response. Three participants (18%) discontinued treatment due to grade 3-4 adverse events. CONCLUSIONS: Ipilimumab-nivolumab shows activity in treatment-refractory granulosa cell tumors, with 25% (n=2/8) of patients experiencing either CR or PR lasting over 4 years.​.

Plasmablastic haemato-lymphoid neoplasm with a complex genetic signature of Burkitt lymphoma responding to bortezomib.

Plasmablastic lymphoma shares many morphologic features with plasmablastic plasma cell myeloma. The activation of MYC oncogene in these lymphomas may be an important pathogenetic element associated with Epstein-Barr virus infection. We describe herein an elderly man with a plasmablastic lymphoid neoplasm displaying unique morphologic, cytogenetic and clinical features. This case might offer additional insights to the complex but fascinating topic of hybrid haemato-lymphoid neoplasms such as plasmablastic lymphoma-myeloma. In addition, the patient responded to the treatment with bortezomib. Newer antimyeloma agents such as bortezomib have shown promise in the treatment of these neoplasms and should further be explored for their therapy.

Recurrent acute pancreatitis and persistent hyperamylasemia as a presentation of pancreatic osteoclastic giant cell tumor: an unusual presentation of a rare tumor.

Giant cell tumors of the pancreas are rare neoplasms divided into three forms: osteoclastic, pleomorphic, and mixed. We report an unusual case of a 62-year-old male presenting with recurrent acute pancreatitis and found to have a mass in the head of the pancreas on routine imaging. Endoscopic retrograde cholangiopancreatography showed a main pancreatic duct stricture, with brush cytology revealing the diagnosis of osteoclastic giant cell tumor of the pancreas. Whipple's procedure was successfully performed for resection of this tumor. and IAP.

Personalized Antibodies for Gastroesophageal Adenocarcinoma (PANGEA): A Phase II Study Evaluating an Individualized Treatment Strategy for Metastatic Disease.

The one-year and median overall survival (mOS) rates of advanced gastroesophageal adenocarcinomas (GEA) are ∼50% and <12 months, respectively. Baseline spatial and temporal molecular heterogeneity of targetable alterations may be a cause of failure of targeted/immunooncologic therapies. This heterogeneity, coupled with infrequent incidence of some biomarkers, has resulted in stalled therapeutic progress. We hypothesized that a personalized treatment strategy, applied at first diagnosis then serially over up to three treatment lines using monoclonal antibodies combined with optimally sequenced chemotherapy, could contend with these hurdles. This was tested using a novel clinical expansion-platform type II design with a survival primary endpoint. Of 68 patients by intention-to-treat, the one-year survival rate was 66% and mOS was 15.7 months, meeting the primary efficacy endpoint (one-sided P = 0.0024). First-line response rate (74%), disease control rate (99%), and median progression-free survival (8.2 months) were superior to historical controls. The PANGEA strategy led to improved outcomes warranting a larger randomized study. SIGNIFICANCE: This study highlights excellent outcomes achieved by individually optimizing chemotherapy, biomarker profiling, and matching of targeted therapies at baseline and over time for GEA. Testing a predefined treatment strategy resulted in improved outcomes versus historical controls. Therapeutic resistance observed in correlative analyses suggests that dual targeted inhibition may be beneficial.This article is highlighted in the In This Issue feature, p. 211.

Evaluation of the Association of Perioperative UGT1A1 Genotype-Dosed gFOLFIRINOX With Margin-Negative Resection Rates and Pathologic Response Grades Among Patients With Locally Advanced Gastroesophageal Adenocarcinoma: A Phase 2 Clinical Trial.

Importance: Patients with locally advanced gastroesophageal adenocarcinoma (ie, stage ≥T3 and/or node positive) have high rates of recurrence despite surgery and adjunctive perioperative therapies, which also have high toxicity profiles. Evaluation of pharmacogenomically dosed perioperative gFOLFIRINOX (fluorouracil, leucovorin, oxaliplatin, and UGT1A1 genotype-directed irinotecan) to optimize efficacy while limiting toxic effects may have value. Objective: To evaluate the coprimary end points of margin-negative (R0) resection rates and pathologic response grades (PRGs) of gFOLFIRINOX therapy among patients with locally advanced gastroesophageal adenocarcinoma. Design, Setting, and Participants: This single-group phase 2 trial, conducted at 2 academic medical centers from February 2014 to March 2019, enrolled 36 evaluable patients with locally advanced adenocarcinoma of the esophagus, gastroesophageal junction, and gastric body. Data analysis was conducted in May 2019. Interventions: Patients received biweekly gFOLFIRINOX (fluorouracil, 2400 mg/m2 over 46 hours; oxaliplatin, 85 mg/m2; irinotecan, 180 mg/m2 for UGT1A1 genotype 6/6, 135 mg/m2 for UGT1A1 genotype 6/7, or 90 mg/m2 for UGT1A1 genotype 7/7; and prophylactic peg-filgastrim, 6 mg) for 4 cycles before and after surgery. Patients with tumors positive for ERBB2 also received trastuzumab (6-mg/kg loading dose, then 4 mg/kg). Main Outcomes and Measures: Margin-negative resection rate and PRG. Results: A total of 36 evaluable patients (27 [78%] men; median [range] age, 66 [27-85] years; 10 [28%] with gastric body cancer; 24 [67%] with intestinal-type tumors; 6 [17%] with ERBB2-positive tumors; 19 [53%] with UGT1A1 genotype 6/6; 16 [44%] with genotype 6/7; and 1 [3%] with genotype 7/7) were enrolled. Of these, 35 (97%) underwent surgery; 1 patient (3%) died after completing neoadjuvant chemotherapy while awaiting surgery. Overall, R0 resection was achieved in 33 of 36 patients (92%); 2 patients (6%) with linitis plastica achieved R1 resection. Pathologic response grades 1, 2, and 3 occurred in 13 patients (36%), 9 patients (25%), and 14 patients (39%), respectively, and PRG 1 was observed in 11 of 24 intestinal-type tumors (46%). Median disease-free survival was 30.1 months (95% CI, 15.0 months to not reached), and median overall survival was not reached (95% CI, 8.3 months to not reached). There were no differences in outcomes by UGT1A1 genotype group. A total of 38 patients, including 2 (5%) with antral tumors, were evaluable for toxic effects. Grade 3 or higher adverse events occurring in 5% or more of patients during the perioperative cycles included diarrhea (7 patients [18%]; 3 of 19 patients [16%] with genotype 6/6; 2 of 16 patients [13%] with genotype 6/7; 2 of 3 patients [67%] with genotype 7/7), anemia (2 patients [5%]), vomiting (2 patients [5%]), and nausea (2 patients [5%]). Conclusions and Relevance: In this study, perioperative pharmacogenomically dosed gFOLFIRINOX was feasible, providing downstaging with PRG 1 in more than one-third of patients and an R0 resection rate in 92% of patients. Trial Registration: ClinicalTrials.gov Identifier: NCT02366819.

Cost-effectiveness of adjuvant paclitaxel and trastuzumab for early-stage node-negative, HER2-positive breast cancer.

OBJECTIVES: Adjuvant paclitaxel and trastuzumab has been shown to be an effective regimen with low risk of cancer recurrence and treatment-related toxicities in early-stage node-negative, HER2-positive breast cancer. We investigated the cost-effectiveness of this regimen. METHODS: A Markov-based microsimulation model with six health states is used to simulate four adjuvant therapy options for women with early-stage node-negative, HER2-positive breast cancer at different age groups. The four treatment arms are 1) adjuvant paclitaxel and trastuzumab (TH), 2) doxorubicin, cyclophosphamide, paclitaxel and trastuzumab (ACTH), 3) docetaxel, carboplatin and trastuzumab (TCH), and 4) no adjuvant trastuzumab (NT). Data from randomized trials were used to estimate treatment efficacy. Societal perspective was used in this cost-effectiveness analysis. Costs were measured in 2016 US dollars (US$) and quality-adjusted life-years (QALYs) was used for health outcomes. Sensitivity analyses were performed to evaluate the impact of uncertainty in parameter estimation. RESULTS: We found that 40-year-old women undergoing TH treatment would have an average of 16.17 QALYs for the cost of $178,650 when lifetime horizon is used. Compared to NT, TH has incremental cost-effectiveness ratios ranged from $10,584 (ages 40-49) to $84,981 (age 80+) per additional QALYs. The sensitivity analysis showed that TH is cheaper and leads to higher QALYs compared to both ACTH and TCH for all age groups and time horizons. CONCLUSIONS: TH is cost-effective for all age groups in the base case scenario and in the sensitivity analysis. In order to reduce the parameter uncertainty, clinical trials with longer follow-up times are needed.

Pharmacodynamic study using FLT PET/CT in advanced solid malignancies treated with a sequential combination of X-82 and docetaxel.

BACKGROUND: A sequential approach, synchronizing cell-cycle specific chemotherapy during VEGFR-TKI treatment breaks, may improve the therapeutic index of this combination therapy. In this study we investigate the safety/tolerability and pharmacodynamic effects of docetaxel used in sequential combination with the novel VEGFR-TKI X-82. METHODS: Patients with advanced solid malignancies underwent 21-day treatment cycles with X-82 administered daily on days 1-14, a treatment break on days 15-20, and docetaxel administered on day 21. Randomization was 1:1 to either a low-dose X-82 (200 mg) or high-dose X-82 (400 mg) arm. Patients were scheduled to undergo four 3'-deoxy-3'-18F-fluorothymidine (FLT) PET/CT scans to assess changes in tumor cell proliferation. PET standardized uptake values (SUV) were summarized for tumors and changes were assessed using mixed effects models. RESULTS: 14 patients were enrolled and treated with median 3.5 cycles (range 0-12). Three patients in the high-dose cohort (50%) and three patients in the low-dose cohort (38%) experienced at least one grade 3 adverse event during the study (infections, cytopenias, electrolyte abnormalities, and vascular complications). Four patients with 13 metastatic tumors underwent FLT PET/CT scanning. During the cycle 1 X-82 exposure period, tumor SUVmax decreased by - 11% (p = 0.04). After administration of docetaxel and the cycle 2 X-82 exposure period, tumor SUVmax decreased - 44% (p = 0.03). CONCLUSIONS: The sequential combination of X-82 and docetaxel was safe and led to diminished FLT uptake. Further, decrease in FLT uptake during cycle 2 (X-82 plus docetaxel) was greater than in cycle 1 (X-82 alone), suggesting sequential chemotherapy enhances the pharmacodynamic effect of therapy.

Phase I Study of an AKT Inhibitor (MK-2206) Combined with Lapatinib in Adult Solid Tumors Followed by Dose Expansion in Advanced HER2+ Breast Cancer.

PURPOSE: Preclinical data support combining AKT inhibitors with HER2-targeted therapies to overcome resistance to treatment. This phase I study combined the investigational AKT inhibitor, MK-2206, with lapatinib to determine the MTD. EXPERIMENTAL DESIGN: The dose escalation cohort enrolled adults with advanced solid tumors, who received MK-2206 dosed 30 to 60 mg every other day and lapatinib 1,000 to 1,500 mg daily continuously, escalated using a 3+3 design. Cycles were 28 days except cycle 1 (35 days, including an initial 8 days of MK-2206 alone to evaluate pharmacokinetic interactions). The dose expansion cohort enrolled adults with advanced HER2(+) breast cancer. RESULTS: Twenty-three participants enrolled in the dose escalation cohort. Dose-limiting toxicities were hyponatremia, fatigue, rash, hypocalcemia, and mucositis. Common toxicities included diarrhea, nausea, and rash. The MTD was reached at MK-2206 45 mg orally every other day and lapatinib 1,500 mg orally daily. Two participants maintained stable disease for >4 months, including a colorectal cancer participant with substantial carcinoembryonic antigen decrease. Of 5 participants in the dose expansion cohort, 2 maintained stable disease for >6 months, including one with prior progression on single-agent lapatinib. Plasma MK-2206 concentrations decreased after addition of lapatinib, but in vitro studies indicate lapatinib increases the intracellular levels of MK-2206. CONCLUSIONS: MK-2206 combined with lapatinib can be tolerated with both drugs above biologically active single-agent doses. Overlapping toxicities result in significant diarrhea and rash, which can be managed medically. Antitumor activity was promising and supports evaluation of AKT inhibitors combined with HER2-targeted therapies. Clin Cancer Res; 22(11); 2659-67. ©2016 AACR.

Update on adjuvant chemotherapy for early breast cancer.

Breast cancer is the second most common cancer in women worldwide. Although most women are diagnosed with early breast cancer, a substantial number recur due to persistent micro-metastatic disease. Systemic adjuvant chemotherapy improves outcomes and has advanced from first-generation regimens to modern dose-dense combinations. Although chemotherapy is the cornerstone of adjuvant therapy, new biomarkers are identifying patients who can forego such treatment. Neo-adjuvant therapy is a promising platform for drug development, but investigators should recognize the limitations of surrogate endpoints and clinical trials. Previous decades have focused on discovering, developing, and intensifying adjuvant chemotherapy. Future efforts should focus on customizing therapy and reducing chemotherapy for patients unlikely to benefit. In some cases, it may be possible to replace chemotherapy with treatments directed at specific genetic or molecular breast cancer subtypes. Yet, we anticipate that chemotherapy will remain a critical component of adjuvant therapy for years to come.

Non-functioning pancreatic neuroendocrine tumors--a case report and review of literature.

PURPOSE: Neuroendocrine tumors of pancreas (PNET) are rare pancreatic neoplasms comprising 1-2% of all pancreatic tumors. The overall prognosis and long-term survival for PNET patients is far better than for patients with exocrine pancreatic cancer. PNETs are classified as functional or nonfunctional based on the presence or absence of a specific clinical syndrome associated with hormone oversecretion. METHODS: We present the case of a 36-year-old female with epigastric and right upper quadrant abdominal pain for 3 months associated with decreased appetite, early satiety and a 20-lb weight loss. On examination, she was cachectic with hepatomegaly. RESULTS: Laboratory assays showed elevated liver and pancreatic enzymes. On computed tomography (CT) scan of the abdomen and pelvis, there was a low-attenuation mass in the distal pancreatic tail measuring 4.7 × 2.4 cm with multiple liver masses, omental implants, left ovarian mass, and a small amount of ascites. CT-guided liver biopsy on pathology was consistent with a well-differentiated pancreatic neuroendocrine carcinoma with metastasis to the liver. Assays for biomarkers of pancreatic neuroendocrine tumors showed an elevated chromogranin A with normal to non-specific elevations of the rest. CONCLUSIONS: The patient and her family declined palliative chemoembolization of the liver lesions or palliative chemotherapy and desired home hospice. We describe here the presentation and course of the case as well as a literature review of PNET with particular emphasis on nonfunctioning PNETs.

Off-pump coronary artery bypass and avoidance of hypothermic cardiac arrest improves early left ventricular function in patients with systolic dysfunction.

OBJECTIVE: Off-pump coronary artery bypass surgery (OPCAB) and beating-heart coronary artery bypass grafting (BH-CAB) performed with cardiopulmonary bypass support are used with increasing frequency in the treatment of coronary artery occlusive disease. The utility of OPCAB and BH-CAB in treating high-risk patients has been studied, but the effects of these procedures on ventricular function have not been thoroughly investigated. METHODS: Data were collected from a database encompassing all patients who underwent isolated coronary revascularization performed by a single surgeon between August 2002 and March 2007. All procedures (n = 507) began as OPCAB operations, but 99 were converted to BH-CAB during surgery. Each patient's ejection fraction (EF) was measured preoperatively and postoperatively (median, 5.0 days after surgery). RESULTS: We found that although the BH-CAB patients tended to be in worse health and to have a lower preoperative EF than the OPCAB patients, both groups of patients had similar improvements in postoperative EF (6.8% vs 5.4%; p = 0.65). In addition, multivariable linear regression showed that a lower preoperative EF, age ≥ 70 years, and cardiomegaly predicted less postoperative EF improvement after coronary revascularization by either OPCAB or BH-CAB. CONCLUSIONS: Both OPCAB and BH-CAB procedures produce significant and similar short-term improvement in EF in patients with coronary disease. This change in EF may account for the subjective clinical improvements seen early after both procedures.

Selective left anterior descending shunting provides effective off-pump myocardial protection.

BACKGROUND: Coronary artery shunting during off-pump coronary artery bypass OPCAB procedures has been addressed only infrequently. To assess the protective effect of shunting, we examined CABG patients' postoperative cardiac enzyme levels and preoperative and postoperative ejection fractions. METHODS: During OPCAB, we selectively shunted the left anterior descending coronary artery (LAD) to provide myocardial protection when ischemia developed. We prospectively gathered data from 408 consecutive patients who underwent OPCAB. Data on shunt status were available for 386 of these patients. A "flow-through" shunt providing perfusion to the distal LAD was used whenever ST-segment elevations greater than 2 mm occurred or when patients had hemodynamic compromise unexplained by cardiac manipulation. Ejection fraction was assessed 1 to 3 days preoperatively and again 3 to 10 days postoperatively. Creatine kinase (muscle/brain) levels were assessed postoperatively for 24 hours. RESULTS: During OPCAB, 99 patients required shunting for presumed ischemia. Thirty-day cardiac mortality was 1.4% (4 of 296 without a shunt; 0 of 90 with a shunt). In patients without a LAD shunt, the mean peak creatine kinase index was 5.3; in patients who needed a shunt, the index was 5.2. Mean ejection fraction improved from 0.536 to 0.589 in the shunted patients and from 0.53.5 to 0.586 in the nonshunted patients. CONCLUSIONS: Selective shunting of the LAD during OPCAB provides effective protection against myocardial ischemia when ischemia is detected by electrocardiogram or when hypotension develops that is unexplained by cardiac manipulation.

Visualization and quantification of intraperitoneal tumors by in vivo computed tomography using negative contrast enhancement strategy in a mouse model of ovarian cancer.

Small animal computed tomography (CT) has poor intrinsic soft tissue contrast, limiting evaluation of intra-abdominal structures. Using standard intravascular-extracellular intravenous contrast (IE-IV) alone is theoretically limited by long acquisition times of traditional small animal scanners that may result in equilibration. We assessed whether a negative contrast strategy of enhancing normal tissue surrounding tumor, instead of the tumor itself, can visualize and quantify intraperitoneal (IP) cancer in a mouse model. Two and a half weeks after IP injection of Hey A8 cells, four groups of three animals each were administered serial dilutions of IV Fenestra LC (RES-IV), oral Gastroview, and IP Optiray 320. Another group of three animals was administered IV Optiray 320 (IE-IV), oral Gastroview, and IP Optiray 320 in successive combinations. Both groups were imaged by CT. Tumor and organ Hounsfield units were measured, and visualization was assessed. With increasing contrast amount, the Hounsfield unit of organs generally increased, whereas that of tumor remained essentially stable. The visualization of abdominal organs and tumor also generally increased with increasing contrast amount. Visualization of tumor and its margins adjacent to liver, spleen, and stomach was significantly better on administering RES-IV. However, for tumor adjacent to bladder, both IE-IV and RES-IV were equivalent. In vivo CT-derived tumor weights correlated highly with ex vivo tumor weights (r = 0.96, P < .0001, n = 15). Thus, CT using negative contrast enhancement strategy allows visualization and quantification of IP tumors. Such a strategy will also enable anatomic localization of functional signal for combination/molecular imaging.