Effect Of Tumor Burden Research Articles

Effect of tumor burden on survival in patients with stage IV EGFR-mutant NSCLC receiving osimertinib monotherapy.

8611 Background: Osimertinib (osi) has traditionally been given as monotherapy for patients (pts) with stage IV EGFR-mutant (EGFRm) non-small cell lung cancer (NSCLC), although acquired resistance remains a challenge. Recent data from the FLAURA2 study demonstrated a progression free survival (PFS) benefit of approximately 9 months (mos) when osi is combined with platinum-pemetrexed chemotherapy. Despite this improvement, combination therapy is associated with higher rates of adverse events, making it challenging to decide which pts should receive TKI + chemo vs TKI monotherapy. Tumor burden (TB) in pts with stage IV EGFRm NSCLC, which may be associated with risk of developing resistant clones on TKI monotherapy, and its association with clinical outcomes has not been examined. Methods: Retrospective, single institution manual case review of pts who received osi monotherapy. Primary objectives were PFS (i.e., oligoprogression requiring local therapy, disease progression (PD) with osi discontinuation, or death) and overall survival (OS) related to extent of TB. Those who did not receive osi monotherapy for stage IV EGFRm NSCLC or discontinued osi for reasons other than PD were excluded. Demographics, comorbidities, performance status, PD-L1 expression, histology, EGFRm subtype, prior TKI use, total number of visceral tumors (TTn), and total number/sites of metastatic disease (MDn) collected for analysis. Extent of TB categorized by TTn (1-4, 5-9, ≥10) and MDn (1-2, 3-4, ≥5). PFS and OS estimated by Kaplan-Meier method and compared using log-rank test. Results: 325 pts eligible for analysis. Median follow-up time was 22.7 mos. Median PFS (mPFS) for the overall cohort was 16.3 mos (95% CI; 13.7 - 18.9) and median OS (mOS) was 31.1 mos (95% CI; 27.4 - 39.3). Pts with a TTn of 1-4 had significantly better mPFS compared to those with a TTn of 5-9 and ≥10 (mPFS: 21.5 vs 16.3 vs 13.4 mos, respectively; P = 0.001). Pts with a TTn ≥10 had significantly worse mOS compared to those with a TTn of 5-9 and 1-4 (23.7 vs 35.1 vs 57.7 mos, respectively; P < 0.0001). Similarly, pts with a MDn of 1-2 had significantly better mPFS and mOS compared to those with a MDn of 3-4 and ≥5 (mPFS: 21.6 vs 11.4 vs 9.0 mos, respectively [P < 0.0001]; mOS: 44.3 vs 20.8 vs 22.4, respectively [P < 0.0001]). Pts with liver and bone mets had significantly worse mPFS and mOS, whereas those with lung and brain mets had worse mOS without affecting PFS. Conclusions: The extent of baseline TB, categorized by TTn and MDn, impacts both PFS and OS in pts with stage IV EGFRm NSCLC treated with osi monotherapy. Pts with “low-TB” (i.e., TTn 1-4, MDn 1-2) appear to have a survival advantage compared to those with “intermediate- or high-TB” (i.e., TTn 5-9 and ≥10, MDn 3-4 and ≥5) and may derive less benefit from the addition of chemotherapy to osi. Prospective, matched real-world treatment cohorts are warranted to optimize treatment strategies for this patient population.

Abstract 4010: Assessing impacts of tumor burden and CAR-T cell dosage on the toxicity and efficacy profile of CD19 CAR-T therapy in a PBMC-humanized mouse model

Abstract Chimeric antigen receptor T-cell (CAR-T) therapy is a significant advancement in treating hematological malignancies, yet it faces challenges due to its variable therapeutic responses and the risk of severe toxicities. This study delves into the effects of tumor burden and CAR-T cell doses on the toxicity profile of the therapy, employing a PBMC-humanized mouse model engrafted with luciferase-labeled Raji B cell lymphoma (Raji-luc). By exploring high vs. low tumor burden and high vs. low CAR-T dose scenarios, we aim to gain insights into the dynamic relationship between these factors and CAR-T-induced toxicity and efficacy. In the first experiment, we established PBMC humanized mouse models with a high tumor burden and a low tumor burden. 10 days (high burden) or 7 days (low burden) after the Raji-luc inoculation, mice were engrafted with 10M human PBMCs and dosed with CD19 autologous CAR-Ts. In mice with low tumor burden, CAR-T treatment demonstrated significant efficacy, as evidenced by IVIS imaging, while the high tumor burden model exhibited reduced efficacy. CAR-T treatment in Raji-bearing mice did not induce weight loss in either high or low burden models. CD19 CAR-T cells effectively reduced the target cell population in peripheral blood, with greater expansion observed in the higher tumor burden model. We also evaluated human cytokine levels post-CAR-T treatment, revealing higher cytokine induction in the high tumor burden model, peaking at 2 days post-treatment. Secondly, in a CAR-T dose-response study, we treated PBMC-humanized Raji-bearing mice with 10M, 15M, and 20M CAR-T cells. Higher CAR-T cell doses (15M and 20M) resulted in observable toxicity measured by body weight loss, while the 10M dose did not. All CAR-T doses effectively slowed tumor growth and induced significant CAR-T cell expansion. Selected human cytokines, such as IL-5 and RANTES, demonstrated a dose-response correlation with CAR-T treatment. Additionally, IL-6 and IL-10 were significantly correlated with tumor burden rather than CAR-T doses. The differential cytokine responses observed in our study provide valuable insights into the utility of the PBMC-humanized mouse model for investigating the biological responses associated with CD19 CAR-T therapy. Our findings underscore the utility of the PBMC-humanized mouse model in assessing variability in toxicity and cytokine responses to CAR-T therapy. This model offers valuable insights into the factors influencing CAR-T treatment outcomes and provides a platform for planning more precise treatment and enhancing the safety and efficacy of CAR-T therapy. Citation Format: Won Lee, Destanie Rose, James G. Keck, Jiwon Yang. Assessing impacts of tumor burden and CAR-T cell dosage on the toxicity and efficacy profile of CD19 CAR-T therapy in a PBMC-humanized mouse model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4010.

A physiologically based pharmacokinetic model for [68Ga]Ga-(HA-)DOTATATE to predict whole-body distribution and tumor sink effects in GEP-NET patients

BackgroundLittle is known about parameters that have a relevant impact on (dis)similarities in biodistribution between various 68Ga-labeled somatostatin analogues. Additionally, the effect of tumor burden on organ uptake remains unclear. Therefore, the aim of this study was to describe and compare organ and tumor distribution of [68Ga]Ga-DOTATATE and [68Ga]Ga-HA-DOTATATE using a physiologically based pharmacokinetic (PBPK) model and to identify factors that might cause biodistribution and tumor uptake differences between both peptides. In addition, the effect of tumor burden on peptide biodistribution in gastroenteropancreatic (GEP) neuroendocrine tumor (NET) patients was assessed.MethodsA PBPK model was developed for [68Ga]Ga-(HA-)DOTATATE in GEP-NET patients. Three tumor compartments were added, representing primary tumor, liver metastases and other metastases. Furthermore, reactions describing receptor binding, internalization and recycling, renal clearance and intracellular degradation were added to the model. Scan data from GEP-NET patients were used for evaluation of model predictions. Simulations with increasing tumor volumes were performed to assess the tumor sink effect.ResultsData of 39 and 59 patients receiving [68Ga]Ga-DOTATATE and [68Ga]Ga-HA-DOTATATE, respectively, were included. Evaluations showed that the model adequately described image-based patient data and that different receptor affinities caused organ uptake dissimilarities between both peptides. Sensitivity analysis indicated that tumor blood flow and blood volume impacted tumor distribution most. Tumor sink predictions showed a decrease in spleen uptake with increasing tumor volume, which seemed clinically relevant for patients with total tumor volumes higher than ~ 550 mL.ConclusionThe developed PBPK model adequately predicted tumor and organ uptake for this GEP-NET population. Relevant organ uptake differences between [68Ga]Ga-DOTATATE and [68Ga]Ga-HA-DOTATATE were caused by different affinity profiles, while tumor uptake was mainly affected by tumor blood flow and blood volume. Furthermore, tumor sink predictions showed that for the majority of patients a tumor sink effect is not expected to be clinically relevant.

Effect of tumor burden and radical surgery on survival difference between upfront, early interval or delayed cytoreductive surgery in ovarian cancer.

ObjectiveWe sought to evaluate the impact on survival of tumor burden and surgical complexity in relation to the number of cycles of neoadjuvant chemotherapy (NACT) in patients with advanced ovarian cancer (OC) with minimal (CC-1) or no residual disease (CC-0).MethodsThis retrospective study included patients with International Federation of Gynaecology and Obstetrics IIIC–IV stage OC who underwent debulking surgery at 4 high-volume institutions between January 2008 and December 2015. We assessed the overall survival (OS) of primary debulking surgery (PDS group), early interval debulking surgery after 3–4 cycles of NACT (early IDS group) and delayed debulking surgery after 6 cycles (DDS group) with CC-0 or CC-1 according to peritoneal cancer index (PCI) and Aletti score.ResultsFive hundred forty-nine women were included: 175 (31.9%) had PDS, 224 (40.8%) early IDS and 150 (27.3%) DDS. Regardless of Aletti score, median OS after PDS was significantly higher than after early IDS or DDS, but the survival difference was higher in women with an Aletti score <8. Among patients with PCI ≤10, median OS after PDS was significantly higher than after early IDS or DDS. In women with PCI >10, there were no differences between PDS and early IDS, but DDS was associated with decreased OS.ConclusionThe benefit of complete PDS compared with NACT was maximal in patients with a low complexity score. In patients with low tumor burden, there was a survival benefit of PDS over early IDS or DDS. In women with high tumor load, DDS impaired the oncological outcome.

Effect of tumor burden and growth rate on treatment outcomes of nivolumab in head and neck cancer.

Nivolumab improves overall survival (OS) in patients with platinum-refractory recurrent and metastatic head and neck squamous cell carcinoma (R/M HNSCC). In one study, however, Kaplan-Meier OS and progression-free survival (PFS) curves for the nivolumab and cytotoxic agent arms crossed at 3-6months, suggesting that patients with initial resistance to immunotherapy might have better outcomes with cytotoxic treatment. Here, we explored the conditions and candidates which are predictive of nivolumab outcomes in R/M HNSCC. We retrospectively reviewed the clinical records of 27 consecutive R/M HNSCC patients treated with nivolumab from 2014 to 2018. Tumor size was evaluated by RECIST ver.1.1. Tumor growth rate (Gr) was defined as 3log(D0/Dpre)/t, where D0 and Dpre are the sum of the diameters of the target lesions (SumTLs) at baseline and pre-baseline, and t is time, with 1t defined as 4weeks. Twenty-five patients were enrolled. Survival was significantly worse in patients with disease progression within 3months. Outcomes appeared poorer in patients with higher pre-treatment Gr and bigger SumTLs at baseline. We therefore explored the association between prognosis, Gr and SumTLs. Recursive partitioning analysis showed that the characteristics of patients with disease progression after 3months were Gr < 0.76 and SumTLs < 31.0mm. Further, Gr < 0.76 and SumTLs < 31.0mm was associated with significantly longer PFS (p = 0.01) and OS (p < 0.01). These results suggest that Gr and SumTLs at baseline are significantly associated with OS and PFS in R/M HNSCC patients treated with nivolumab.

Tumor Size Matters-Understanding Concomitant Tumor Immunity in the Context of Hypofractionated Radiotherapy with Immunotherapy.

The purpose of this study was to determine the dynamic contributions of different immune cell subsets to primary and abscopal tumor regression after hypofractionated radiation therapy (hRT) and the impact of anti-PD-1 therapy. A bilateral syngeneic FSA1 fibrosarcoma model was used in immunocompetent C3H mice, with delayed inoculation to mimic primary and microscopic disease. The effect of tumor burden on intratumoral and splenic immune cell content was delineated as a prelude to hRT on macroscopic T1 tumors with 3 fractions of 8 Gy while microscopic T2 tumors were left untreated. This was performed with and without systemic anti-PD-1. Immune profiles within T1 and T2 tumors and in spleen changed drastically with tumor burden in untreated mice with infiltrating CD4+ content declining, while the proportion of CD4+ Tregs rose. Myeloid cell representation escalated in larger tumors, resulting in major decreases in the lymphoid:myeloid ratios. In general, activation of Tregs and myeloid-derived suppressor cells allow immunogenic tumors to grow, although their relative contributions change with time. The evidence suggests that primary T1 tumors self-regulate their immune content depending on their size and this can influence the lymphoid compartment of T2 tumors, especially with respect to Tregs. Tumor burden is a major confounding factor in immune analysis that has to be taken into consideration in experimental models and in the clinic. hRT caused complete local regression of primary tumors, which was accompanied by heavy infiltration of CD8+ T cells activated to express IFN-γ and PD-1; while certain myeloid populations diminished. In spite of this active infiltrate, primary hRT failed to generate the systemic conditions required to cause abscopal regression of unirradiated microscopic tumors unless PD-1 blockade, which on its own was ineffective, was added to the RT regimen. The combination further increased local and systemically activated CD8+ T cells, but few other changes. This study emphasizes the subtle interplay between the immune system and tumors as they grow and how difficult it is for local RT, which can generate a local immune response that may help with primary tumor regression, to overcome the systemic barriers that are generated so as to effect immune regression of even small abscopal lesions.

Effect of Tumor Burden on Tumor Aggressiveness and Immune Modulation in Prostate Cancer: Association with IL-6 Signaling.

Local treatment is known to improve survival in men with locally advanced prostate cancer (LAPC), but the underlying mechanisms remain unclear. In the present study, we examined the role of tumor burden in tumor aggressiveness, as well as the pathway responsible for these changes. We used human and murine prostate cancer cell lines to examine the role of tumor burden in tumor aggressiveness, as well as its correlation with cancer stem cell (CSC) marker levels and IL-6 signaling. Furthermore, 167 prostate cancer biopsy specimens were analyzed in terms of correlations of IL-6 and CD44 levels with clinical patient characteristics. Data from preclinical models showed that larger tumor burden was associated with more aggressive tumor growth associated and increased CD44 expression. Using cellular experiments and orthotopic tumor models, we showed that CD44+ prostate cancer cells have CSC-like properties, enhanced epithelial–mesenchymal transition (EMT), and a more immunosuppressive microenvironment. There was a significant correlation between IL-6 and CD44 levels based on in vitro testing of clinical samples. Blockade of IL-6/STAT3 signaling attenuated the expression of CD44, CSC-like properties, and aggressive tumor behavior in vitro and in vivo. In conclusion, CD44 expression is significantly associated with tumor aggressiveness in prostate cancer and activation of IL-6 signaling leads to a suitable microenvironment for the induction of CD44 expression. Based on our study, reduced tumor burden was associated with attenuated IL-6 signaling and augmented tumor rejection in the microenvironment, which might mediate the benefit of clinical adoption with aggressive local therapy.

Effects of Tumor Burden on Reference Tissue Standardized Uptake for PET Imaging: Modification of PERCIST Criteria.

Purpose To examine the effect metabolic burden (tumor and/or cardiac myocyte uptake) has on fluorine 18 fluorodeoxyglucose (FDG) distribution in organs and tissues of interest. Materials and Methods Positron emission tomographic (PET)/computed tomographic (CT) scans at the Ann Arbor Veterans Affairs hospital from January to July 2015 were reviewed. A total of 107 scans (50 patients; mean age, 64.3 years ± 13.2 [standard deviation]) had metabolic tissue burden assessed by using total lesion glycolysis (TLG) obtained from autosegmentation of the tumor and/or cardiac tissue. Standardized uptake value (SUV) and subsequent normalized SUV uptake in target organs and tissues were compared with 436 FDG PET/CT scans previously reported in 229 patients as a function of TLG to describe the effect(s) that metabolic burden has on reference tissue (blood pool, liver, and brain) FDG uptake. Subsequent regression by using linear mixed-effects models was used. If the slope of the regression was significantly (P < .05) different than zero, then an effect from TLG was present. Results There was a negative inverse relationship (P < .0001) between FDG uptake within reference tissues (blood pool, liver, and brain) and TLG in comparison to the study population at similar blood glucose levels. This TLG effect was no longer statistically significant (P > .05) when FDG uptake was normalized to a reference tissue (eg, blood pool or liver). Conclusion Metabolic tissue burden can have a significant effect on SUV measurements for PET imaging. This effect can be mitigated by normalizing FDG uptake to a reference tissue. © RSNA, 2018.

147 - Effect of Tumor Burden on Safety and Feasibility of Three-Port Robotic-Assisted Myomectomy

Study Objective: To assess optimal candidates for a three-port robotic-assisted myomectomy.

Abstract No. 506 - Effect of tumor burden on contralateral lobe hypertrophy after y90 radioembolization

Abstract No. 506 - Effect of tumor burden on contralateral lobe hypertrophy after y90 radioembolization

Abstract No. 36 - Effect of tumor burden on contralateral lobar hypertrophy after portal vein embolization

Abstract No. 36 - Effect of tumor burden on contralateral lobar hypertrophy after portal vein embolization

Abstract 2181: Differential expression of genes related to autoimmunity and metabolism in Stage I NSCLC from patients with COPD

Abstract Chronic obstructive pulmonary disease increases lung cancer risk 3-fold, but individuals with COPD may not qualify for lung cancer screening if their age or smoking histories do not meet eligibility criteria. Genomics might reveal genes differentially active in lung tumors from COPD patients, identifying pathways associated with lung cancer in the COPD setting. We used mRNA profiling to identify differences in Stage I non-small cell lung cancers (NSCLC) from patients with and without COPD. COPD was determined by pre-surgery Pulmonary Function Tests (PFTs); the GOLD score was calculated from FEV1 and FVC measurements. Stage I cases were chosen to minimize effect of tumor burden on PFTs. After extraction of mRNA from frozen tumor specimens (71 adenocarcinoma and 24 squamous cell carcinoma), the Illumina HT-12 v4 BeadChip was used to measure mRNA expression. All cases passed RNA quality checks, had not received neo-adjuvant therapy, and had pre-surgical PFT results. 44% of cases were GOLD II-IV (COPD positive) and 56% were GOLD 0-I (COPD negative). In an unbiased examination using the limma R package, 5,789 probes showed expression above background and variation in expression. These probes were compared in COPD positive and negative tumors; no probes were significantly different after multiple comparisons adjustment. In an examination of KEGG pathways by gene set enrichment analysis (GSEA) using a t-test or a linear model that adjusted for age, race, sex and smoking status, 31 pathways (17 in squamous cell and 14 in adenocarcinoma) were identified that were differentially expressed between COPD positive and negative tumors (p value &amp;lt; 0.025 in a 2-tailed test). There was no overlap in significant KEGG Pathways between the two histologies. In squamous cell carcinoma, DNA Replication and Mismatch Repair were repressed in COPD positive tumors, while many Autoimmunity and Infection pathways were activated. In adenocarcinoma, COPD positive tumors showed repression of metabolic pathways including P450, fatty acid, and pentose metabolism. Ingenuity pathway analysis predicted upstream regulators that are reported to control differentially expressed genes contained in the significant KEGG pathways. In squamous cell lung carcinoma, IL27 (p = 2.96 E-36, activation score 3.00), interferon gamma (p = 1.65 E-58, activation score 5.57), and tumor necrosis factor (p = 2.01 E-44, activation score 3.92) were the three top upstream regulators. In adenocarcinoma, PPAR alpha/RXRA (p = 4.83 E -15, inhibition score -2.84), TP53 (p = 3.63 E-08, inhibition score -2.06), and HNF1A (p = 3.88 -08, inhibition score -2.59) were the top three upstream regulators. Results show that distinct pathways are affected by COPD in lung squamous cell and adenocarcinoma, and identify potential biomarkers such as IL27 that may drive squamous cell carcinoma development, while loss of PPAR activity may drive adenocarcinoma, in smokers with COPD. Supported by P50 CA090440. Citation Format: Jill M. Siegfried, Kan Shang, Cavan Reilly, Laura P. Stabile. Differential expression of genes related to autoimmunity and metabolism in Stage I NSCLC from patients with COPD. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2181. doi:10.1158/1538-7445.AM2015-2181

Outcomes of liver-directed therapy for metastatic carcinoid tumors.

356 Background: Patients with liver metastases from carcinoid tumors can have a variable and often indolent disease course. That said, left untreated, these tumors will often lead to the death of the patient secondary to the effects of tumor burden within the liver and the sequelae of carcinoid syndrome. In this study, we evaluate the effects of liver directed therapy on disease-specific survival in patients with liver metastases from carcinoid tumors. Methods: The California Cancer Registry was queried for patients with liver metastases from a primary carcinoid tumor. Demographic data was recorded. Patients were subdivided into six groups: those who received 1) no liver directed therapy, 2) surgical resection only, 3) trans-arterial chemoembolization (TACE) only, 4) radioembolization (RE) only, 5) surgical resection plus TACE, or 6) surgical resection plus RE. Kaplan-Meier curves were applied to estimate 10 year disease-specific survival. Results: 4,566 patients were identified with liver metastases from a primary carcinoid tumor, and 4,277 patients with complete clinical information included in the analysis. A slight majority of cases were male (51.4%), 183 (4%) were less than 40 years of age, 2,006 (44%) were between 40 and 65 years, and 2,363 (52%) were over 65. The 10 year median disease-specific survival was 66 months for those treated with TACE only, 80 months for those who received no liver directed therapy and 111 months for those who received liver resection plus TACE. The 10 year median survival has not yet been reached for the other groups. When compared directly, surgery plus RE had a trend toward better disease specific survival than surgery plus TACE, though statistical significance was not reached. Conclusions: While patients with liver metastases from carcinoid tumors often have an indolent disease course, liver directed therapy may help improve disease-specific survival. Surgical treatment, when completely resectable, remains the best treatment, although many patients will not have disease that is amenable to complete resection. In these cases, resection with the addition of RE appears to be more effective in improving disease-specific survival than other forms of liver directed therapy alone or in combination.

Abstract B52: Characterizing the MDSCs phenotypes, expansion, and trafficking pattern and associated tumor-induced immune dysfunction

Abstract Among the prerequisites to be effective, immunotherapy must work in the presence of the host immunosuppression. Myeloid-derived suppressor cells (MDSCs) are one of the cellular mediators that have a role in limiting the induction of adaptive immune response and host responses to immunotherapy. MDSCs are an immature, heterogeneous cellular population, including hematopoietic precursors for granulocytes, macrophages, dendritic cells, and endothelial cells. They are infrequent in healthy hosts, but increase during tumor progression as a result of dysregulated myeloid cell expansion and differentiation. Tumor growth is frequently associated with an increased frequency of MDSCs that results in a loss in T-cell number and function through increased ROS and peroxynitrites production and arginase 1 (ARG1) and nitric oxide synthase 2 (NOS-2) upregulation. A better understanding of MDSCs expansion and the regulation of biodistribution and arrest would improve interventional strategies and cancer immunotherapy outcomes. Using five mammary tumor models, we have examined tumor-associated expansion of MDSCs and observed that this occurs in an organ-specific manner. Murine MDSCs can be subdivided into phenotypically and functionally distinct sub-populations according to Gr-1 expression levels; the CD11b+Gr-1 dim MDSCs with monocytic nuclei and strong T-cell suppressive activity, and CD11b+Gr-1bright having ring-shaped nuclei (polymorphonuclear cells) and a lower T-cell suppression profile. These cells can also be subset based on the expression of Ly-6C which is highly expressed on immature, bone marrow-derived cells and combined this Gr-1 expression Our studies revealed a significant increase in the Ly-6Cbright expression on the CD11b+Gr-1dim MDSCs in all organs studied in tumor-bearing mice as compared to non-tumor-bearing mice. In association with the increase in CD11b+Gr-1dimLy-6Cbright cells in the tumor non-parenchymal cells of 4T1 tumor bearing mice, increased transcripts levels of cytokines associated with MDSCs expansion (granulocyte-colony stimulating factor [G-CSF]) and MDSCs-associated immunosuppression (ARG-1, NOS-2, and cyclooxygenase 2 [COX-2]) while lower levels of these cytokines were observed in tumor NPCs from Cl66 tumor-bearing mice and non-tumor-bearing mice. In association with the increase in MDSCs and loss of T-cells in the 4T1 tumor-bearing mice there was a significant decrease in cytokine transcript levels that can enhance immune response (interferon gamma [IFN-γ] and interleukin 12 [IL-12]) from tumor non-parenchymal cells (NPCs) in 4T1 tumor bearing mice as compared to Cl66 tumor bearing mice and non-tumor bearing mice. Studies to assess where the MDSCs were expanding revealed that in 4T1 tumor bearing mice, frequency of the proliferating MDSCs is increased only in the spleen and liver compared to the non-tumor-bearing mice. Our studies also examined the affect of tumor burden on the trafficking of MDSCs. We observed that, after adoptive transfer of MDSCs isolated from 4T1 tumor-bearing mice, they arrest initially within the lungs in non-tumor-bearing mice. While in 4T1 tumor-bearing mice they rapidly transverse the lungs with arrest within the tumor tissue. We and others reported that the increase in MDSCs frequencies is associated with a decrease in CD3+ cells function and numbers. We observed a decrease in frequency of all T-cell subsets in the thymus of tumor bearing mice tested compared to the non-tumor-bearing mice suggesting defects in T-cell maturation associated with tumor burden. We investigated the effect of tumor burden on the phenotype of the CD3+ cells using the Annexin V staining and found that 4T1 tumor bearing mice have increased frequency of Annexin V positive CD3+ T-cells that are infiltrating tumor tissue compared to those in other organs. Citation Information: Clin Cancer Res 2010;16(14 Suppl):B52.

Effect of tumor burden on myeloid derived suppressor cells and cytokine expression

Tumors growth has been suggested to suppress host immunity, including tumor infiltration by histocytes and T cells. We report herein that the frequency of myeloid derived suppressor cells (MDSCs) are significantly increased in the tumors, spleens, lungs and livers of mice bearing orthotopic clone‐66, mammary tumors in a tumor burden and duration dependant manner, while T cell numbers are suppressed. The increases in tumor burden and MDSC number are associated with significantly increased levels of VEGF‐a transcripts from tumor infiltrating myeloid cells (TIMCs), but not spleen cells or tumor parenchyma. Tumor burden and MDSC numbers are also directly correlated with G‐ and GM‐CSF transcript levels from the tumor parenchyma. In contrast, T cell numbers are inversely correlated with NOS‐2, ARG‐1 and COX‐2 transcript levels in the TIMCs, but not spleen cells, while MDSC numbers in the spleen and TIMCs are directly correlated with these enzyme transcript levels. These results suggest that the tumor associated increase in MDSC numbers was associated with G‐ and GM‐CSF and VEGF‐a secretion, while the activation of the MDSCs and secretion of ARG‐1 and NOS‐2 was associated with increased COX‐2 activity.

Is There Any Effect of Tumor Burden on Hemostatic Parameters in Cancer Patients? A Case—Control Study of Hemostatic Abnormalities and Anticardiolipin Antibodies in Solid Tumors

Hemostatic complications are one of the leading causes of mortality in cancer patients. In the present study, we assessed the hemostatic parameters and anticardiolipin antibodies in patients with solid tumors (n = 104) and healthy controls (n = 25) and also find out whether the abnormalities in these hemostatic parameters vary related to tumor burden. Prothrombin time, activated partial thromboplastine time, D-dimer, and fibrinogen as hemostatic parameters were determined by photo-optometric clot detection system, and serum anticardiolipin levels were measured by enzyme-linked immunosorbent assay. The plasma levels of fibrinogen, D-dimer, and serum anticardiolipin IgM levels in cancer patients were significantly higher compared with those in controls (P < .001, P = .001, and P = .01, respectively). Only fibrinogen levels were significantly higher in metastatic group than nonmetastatic group (P < .001 ). Hemostatic abnormalities that are detected in asymptomatic cancer patients may not give any clue about tumor burden or stage of the cancer patients.

Effect of tumor burden on differentiation of T lymphocytes in the peripheral blood of patients with colorectal cancer

To analyze the effect of tumor burden on the differentiation of T1 and T2 cells and its implication in patients with colorectal cancer. Peripheral venous blood samples were obtained from 20 patients with primary colorectal cancer before and 7 days after the operation, radical operation in 17 patients and palliative resection in 3 patients. Twenty sex and age-matched patients with benign diseases treated in the same period were used as controls. T1 and T2 cells in the peripheral blood were evaluated by detecting the intracellular interferon-gamma and interleukin-4 production with 4-color flow cytometry. Lymphocyte subsets in the peripheral blood were also measured by flow cytometry. At the time of diagnosis, the percentage of T1 and T2 cells in the peripheral lymphocytes of the case group was lower significantly than that of the control group (P = 0.006, and P = 0.017). There was no significant difference in the T, CD4(+) T, CD8(+) T, B, and NK cells between the two groups. After getting rid of the tumor burden, the percentage of T1 cells increased, however, not significantly (P > 0.05). And the percentage of T2 cells increased significantly (P = 0.020). The percentages of T1 cell of the patients with the tumor > or = 5 cm and of the patients with poorly differentiated tumors were significantly lower than those of the patients with the tumor < 5 cm and of the patients with well or moderately differentiated tumors (P = 0.064, and P = 0.072). The percentage of T1 cells in the patients with lymph node metastasis and stage III approximately IV tumor were lower significantly than those of the patients without lymph node metastasis and those with stage I approximately II tumor (P = 0.033 and P = 0.033). No significant differences were found between the population of T1 cells and such factors as tumor size, serosa invasion, and distant metastasis. Tumor load suppresses the differentiation of T1 and T2 cells in the patients with colorectal cancer significantly, and may be an important factor in the development of immunosuppression. After getting rid of the tumor burden, the percentages of T1 and T2 increase in a short time, and the immunologic function is improved. Determination of T1 may be helpful to indicate the prognosis of colorectal cancer.

Effects of hepatic metastases on resting energy expenditure in patients with colorectal cancer.

There are frequent reports that cancer causes an increase in resting energy expenditure (REE), and the presence of hepatic metastases is said to increase REE further. The effect of tumour burden on REE has been measured in 24 patients before and following surgery for colorectal cancer. Fifteen patients had a 'curative' resection whereas nine patients were found to have hepatic metastases at the time of surgery. No significant differences in REE were found between the groups either before surgery or at follow-up, by which time all 15 curative resection patients were tumour free and the remaining nine had progression of their hepatic disease. It is concluded that neither surgical removal of the primary tumour nor progression of metastatic hepatic disease significantly alters REE in patients with colorectal cancer.

Efforts to Control the Errant Products of a Targeted In vivo Generator

Alpha-particle immunotherapy by targeted alpha-emitters or alpha-emitting isotope generators is a novel form of extraordinarily potent cancer therapy. A major impediment to the clinical use of targeted actinium-225 (225Ac) in vivo generators may be the radiotoxicity of the systemically released daughter radionuclides. The daughters, especially bismuth-213 (213Bi), tend to accumulate in the kidneys. We tested the efficacy of various pharmacologic agents and the effect of tumor burden in altering the pharmacokinetics of the 225Ac daughters to modify their renal uptake. Pharmacologic treatments in animals were started before i.v. administration of the HuM195-225Ac generator. 225Ac, francium-221 (221Fr), and 213Bi biodistributions were calculated in each animal at different time points after 225Ac generator injection. Oral metal chelation with 2,3-dimercapto-1-propanesulfonic acid (DMPS) or meso-2,3-dimercaptosuccinic acid (DMSA) caused a significant reduction (P < 0.0001) in the renal 213Bi uptake; however, DMPS was more effective than DMSA (P < 0.001). The results with DMPS were also confirmed in a monkey model. The renal 213Bi and 221Fr activities were significantly reduced by furosemide and chlorothiazide treatment (P < 0.0001). The effect on renal 213Bi activity was further enhanced by the combination of DMPS with either chlorothiazide or furosemide (P < 0.0001). Competitive antagonism by bismuth subnitrate moderately reduced the renal uptake of 213Bi. The presence of a higher target-tumor burden significantly prevented the renal 213Bi accumulation (P = 0.003), which was further reduced by DMPS treatment (P < 0.0001). Metal chelation, diuresis with furosemide or chlorothiazide, and competitive metal blockade may be used as adjuvant therapies to modify the renal accumulation of 225Ac daughters.

The effect of tumour burden in human leukaemia bearing SCID mice on immunotoxin therapy outcome

The effect of tumour burden in human leukaemia bearing SCID mice on immunotoxin therapy outcome