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Background: A high rate of glycolysis leading to elevated lactate content has been linked to poor clinical outcomes in patients with head and neck and cervical cancer treated with radiotherapy. Although the biological explanation for this relationship between lactate and treatment response remains unclear, there is a continued interest in evaluating strategies of targeting metabolism to enhance the effectiveness of radiotherapy. The goal of this study was to investigate the effect of metabolic-targeting through HIF-1α inhibition and the associated changes in glycolysis, oxygen consumption and response on the efficacy of high-dose single-fraction radiotherapy (HD-SFRT)., Methods: HIF-1α wild-type and HIF-1α knockdown FaDu and ME180 xenograft tumors were grown in the hind leg of mice that were placed in an environmental chamber and exposed to different oxygen conditions (air-breathing and hypoxia). Ex vivo bioluminescence microscopy was used to measure lactate and ATP levels and the hypoxic fraction was measured using EF5 immunohistochemical staining. The oxygen consumption rate (OCR) in each cell line in response to in vitro hypoxia was measured using an extracellular flux analyzer. Tumor growth delay in vivo was measured following HD-SFRT irradiation of 20 Gy., Results: Targeting HIF-1α reduced lactate content, and increased both oxygen consumption and hypoxic fraction in these tumors after exposure to short-term continuous hypoxia. Tumors with intact HIF-1α subjected to HD-SFRT immediately following hypoxia exposure were less responsive to treatment than tumors without functional HIF-1α, and tumors irradiated under air breathing conditions regardless of HIF-1α status., Conclusions: Blocking the HIF1 response during transient hypoxic stress increased hypoxia, reduced lactate levels and enhanced response to HD-SFRT. This strategy of combining hypofractionated radiotherapy with metabolic reprogramming to inhibit anaerobic metabolism may increase the efficacy of HD-SFRT through increased oxygen consumption and complementary killing of radiosensitive and hypoxic, radioresistant cells.

Compared to FDG, the signal of 18 F-labelled hypoxia-sensitive tracers in tumours is low. This means that in addition to the presence of hypoxic cells, transport properties contribute significantly to the uptake signal in static PET images. This sensitivity to transport must be minimized in order for static PET to provide a reliable standard for hypoxia quantification. A dynamic compartmental model based on a reaction-diffusion formalism was developed to interpret tracer pharmacokinetics and applied to static images of FAZA in twenty patients with pancreatic cancer. We use our model to identify tumour properties-well-perfused without substantial necrosis or partitioning-for which static PET images can reliably quantify hypoxia. Normalizing the measured activity in a tumour voxel by the value in blood leads to a reduction in the sensitivity to variations in 'inter-corporal' transport properties-blood volume and clearance rate-as well as imaging study protocols. Normalization thus enhances the correlation between static PET images and the FAZA binding rate K 3 , a quantity which quantifies hypoxia in a biologically significant way. The ratio of FAZA uptake in spinal muscle and blood can vary substantially across patients due to long muscle equilibration times. Normalized static PET images of hypoxia-sensitive tracers can reliably quantify hypoxia for homogeneously well-perfused tumours with minimal tissue partitioning. The ideal normalizing reference tissue is blood, either drawn from the patient before PET scanning or imaged using PET. If blood is not available, uniform, homogeneously well-perfused muscle can be used. For tumours that are not homogeneously well-perfused or for which partitioning is significant, only an analysis of dynamic PET scans can reliably quantify hypoxia.

Unlabelled: Pancreatic cancers are thought to be unusually hypoxic, which might sensitize them to drugs that are activated under hypoxic conditions. In order to develop this idea in the clinic, a minimally invasive technique for measuring the oxygenation status of pancreatic cancers is needed., Methods: We tested the potential for minimally invasive imaging of hypoxia in pancreatic cancer patients, using the 2-nitroimidazole PET tracer (18)F-fluoroazomycin arabinoside (or (18)F-1-α-D-[5-fluoro-5-deoxyarabinofuranosyl]-2-nitroimidazole [(18)F-FAZA]). Dynamic and static scans were obtained in 21 patients with either locally advanced or metastatic disease. The hypoxic fraction was determined in the 2-h static scans as the percentage of voxels with SUVs more than 3 SDs from the mean values obtained for skeletal muscle., Results: Hypoxia was detected in 15 of 20 evaluable patients, with the hypoxic fraction ranging from less than 5% to greater than 50%. Compartmental analysis of the dynamic scans allowed us to approximate the tumor perfusion as mL/min/g of tissue, a value that is independent of the extent of hypoxia derived from tracer uptake in the 2-h static scan. There was no significant correlation between tumor perfusion and hypoxia; nor did we see an association between tumor volume and hypoxia., Conclusion: Although pancreatic cancers can be highly hypoxic, a substantial proportion appears to be well oxygenated. Therefore, we suggest that a minimally invasive technique such as the one described in this study be used for patient stratification in future clinical trials of hypoxia-targeting agents., (© 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.)

The results from many studies indicate that most solid tumors, regardless of site of origin, contain hypoxic regions. Experimental studies have demonstrated that, apart from the well-known protective effect of hypoxia on the radiation response of cells and tissues, hypoxic conditions can also result in modified gene expression patterns, causing (to a greater or lesser extent in different cell populations) genomic instability, increased invasive capacity, higher propensity to metastasize, enhanced stem cell properties, and ability to survive nutrient deprivation. Clinical trials of hypoxia-targeted treatments have demonstrated improved local tumor control and patient survival in a number of tumor sites. However, our improved understanding of the underlying biology of cellular responses to hypoxia, and its potential interactions with the heterogeneous nature of tumor phenotypes, makes it likely that not every tumor that contains regions of hypoxia would necessarily need (or benefit from) such treatments. New more effective treatments are emerging, but it is likely that these treatments would have the biggest clinical effect in situations where tumor hypoxia is a primary driver of cancer behavior. The challenge for the Radiation Oncology community is the development of robust precision cancer medicine strategies for identifying patients with such tumors, in the setting of other etiological, genomic, and host-tumor factors, and treating these patients with the appropriate hypoxia-targeting strategy to reduce the effect of hypoxia on radiation treatment response. In this context, it is important to consider not only the hypoxic state of the tumor at diagnosis but also the changing characteristics of this state during the course of treatment., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Purpose: Tumor hypoxia is an important determinant of outcome in many human malignancies and is associated with treatment resistance and metastases. The aim of this study was to determine the effect of hypoxia in patients with prostate cancer treated with radiotherapy., Experimental Design: Tumor hypoxia was measured in 247 patients with clinically localized prostate cancer before radiotherapy, with or without hormonal therapy. The median pO(2) was 6.8 mm Hg and the median hypoxic percentage less than 10 mm Hg (HP(10)) was 63%. The median follow-up was 6.6 years., Results: The 5-year biochemical relapse-free rate (bRFR) was 78%. Prostrate-specific antigen and Gleason score were both associated with biochemical relapse and formed a baseline clinical model. The effect of hypoxia was found to vary with the duration of patient follow-up. HP(10), when added to the clinical model, was an independent predictor of early bRFR (P = 0.019). The relationship between hypoxia and early bRFR was more pronounced when the analysis was restricted to 142 patients with bulk tumor at the site of the oxygen measurements (P = 0.004). Hypoxia was the only factor predictive of local recurrence in 70 patients who had biopsies conducted during follow-up (P = 0.043), again with the effect being greatest early after completing treatment., Conclusions: This is the largest clinical study of prostate cancer hypoxia with direct measurement of tumor oxygen levels. It shows that hypoxia is associated with early biochemical relapse after radiotherapy and also with local recurrence in the prostate gland., (©2012 AACR.)

Tumor oxygenation status is considered one of the important prognostic markers in cancer since it strongly influences the response of cancer cells to various treatments; in particular, to radiation therapy. Thus, a proper and accurate assessment of tumor oxygen distribution before the treatment may highly affect the outcome of the treatment. The heterogeneous nature of tumor hypoxia, mainly influenced by the complex tumor microenvironment, often makes its quantification very difficult. The usual methods used to measure tumor hypoxia are biomarkers and the polarographic needle electrode. Although these techniques may provide an acceptable assessment of hypoxia, they are invasive and may not always give a spatial distribution of hypoxia, which is very useful for treatment planning. An alternative method to quantify the tumor hypoxia is to use theoretical simulations with the knowledge of tumor vasculature. The purpose of this paper is to model tumor hypoxia using a known spatial distribution of tumor vasculature obtained from image data, to analyze the accuracy of polarographic needle electrode measurements in quantifying hypoxia, to quantify the optimum number of measurements required to satisfactorily evaluate the tumor oxygenation status, and to study the effects of hypoxia on radiation response. Our results indicate that the model successfully generated an accurate oxygenation map for tumor cross-sections with known vascular distribution. The method developed here provides a way to estimate tumor hypoxia and provides guidance in planning accurate and effective therapeutic strategies and invasive estimation techniques. Our results agree with the previous findings that the needle electrode technique gives a good estimate of tumor hypoxia if the sampling is done in a uniform way with 5-6 tracks of 20-30 measurements each. Moreover, the analysis indicates that the accurate measurement of oxygen profile can be very useful in determining right radiation doses to the patients.

Hypoxia is a feature of many human malignancies, and leads to aggressive clinical behavior and recurrence after treatment. Here, we show for the first time that androgen withdrawal reduces prostate cancer hypoxia in patients. Oxygen measurements were done in 248 patients with clinically localized prostate cancer prior to radiotherapy, and showed hypoxia of potential biological and clinical significance. In 22 of these patients, prostate oxygen levels were measured both before and after 30 to 145 days of the androgen antagonist bicalutamide. There was a significant reduction in tumor hypoxia with androgen withdrawal (P=0.005). The median pO(2) increased from 6.4 to 15 mm Hg, and the hypoxic proportion decreased from 40% to 31%. However, the response was heterogeneous, with improvement in 12 patients, stable oxygen readings in 9 patients and worsening hypoxia in 1 patient. Among the responding patients, the median pO(2) increased from 4.9 to 33 mm Hg, and the hypoxic proportion decreased from 51% to 23%. There was no apparent relationship between the change in oxygenation and baseline prostatic volume, T category, Gleason score, prostate-specific antigen levels, the duration of treatment with bicalutamide, or the change in prostate-specific antigen levels with bicalutamide. These results might, in part, explain the improved patient outcome that has been observed in clinical trials of radiotherapy and hormones, and suggest a role for novel therapeutic agents that block the molecular response to hypoxia in prostate cancer either alone or in combination with other established treatments.

Increasingly, the tumor microenvironment and hypoxia are being studied as potential prognostic factors in prostate cancer given their effects on the hypoxia inducible factor-1alpha and vascular endothelial growth factor signaling pathways. Based on immunohistochemical studies using hypoxic cell markers and direct oxygen-electrode measurements, clinically relevant levels of hypoxia are detected in 30-90% of prostate cancers. Exciting new data suggest that hypoxia can alter cell-cycle checkpoints and DNA repair within the prostate epithelium, thereby driving genetic instability and tumor aggression. Novel therapies designed to target the hypoxic response and resulting defective DNA repair may therefore be effective as chemoprevention agents or as adjuncts to surgery, radiotherapy and chemotherapy to improve clinical outcome.

Radiotherapy (RT) with concurrent cisplatin (CRT) is standard treatment for locally advanced cervical cancer. However, not all patients benefit from the addition of cisplatin to RT alone. This study explored the value of pretreatment tumor interstitial fluid pressure (IFP) and hypoxia measurements as predictors of cisplatin response in 291 patients who were treated with RT (1994-1998) or RT plus concurrent cisplatin (1999-2009). Clinical characteristics were similar between the two groups, apart from a greater proportion of patients with pelvic lymph node metastases and hypoxic tumors in the CRT cohort. Patients were followed for a median duration of 5.6 years. Information about recurrence and survival was recorded prospectively. The addition of cisplatin to RT improved survival compared to treatment with RT alone (HR 0.61, p = 0.0097). This improvement was confined to patients with high-IFP tumors at diagnosis (HR 0.40, p = 0.00091). There was no benefit of adding cisplatin in those with low-IFP tumors (HR 1.05, p = 0.87). There was no difference in the effectiveness of cisplatin in patients with more or less hypoxic tumors. In conclusion, patients with locally advanced cervical cancer and high tumor IFP at diagnosis have greater benefit from the addition of cisplatin to RT than those with low IFP. This may reflect high tumor cell proliferation, which is known to influence IFP, local tumor control and patient survival. [ABSTRACT FROM AUTHOR]

Rationale: The tumor microenvironment (TME) is heterogeneous including both malignant and host cell components as well as regions of hypoxia, elevated interstitial fluid pressure (IFP) and poor nutrient supply. The quantitative extent to which the microenvironmental properties of primary tumors are recapitulated in xenograft models is not well characterized. Methods: Xenografts were generated by implanting tumor biopsies directly into the cervix of mice to create a panel of orthotopically-passaged xenografts (OCICx). Tumors were grown to ∼1 cm (diameter) and IFP measurements recorded prior to sacrifice. Enlarged para-aortic lymph nodes (>1-2 mm) were excised for histologic confirmation of metastatic disease. Quantitative histological analysis was used to evaluate hypoxia, proliferation, lymphatic and blood vessels in the epithelial and stromal regions of the xenografts and original patient tumour. Results: IFP and nodal disease were not correlated with tumor engraftment. IFP measurements in the xenografts were generally lower than those in the patient's tumor. Lymphatic metastasis increased with passage number as did levels of hypoxia in the epithelial component of the xenografts. The blood vessel density in the stromal component of the xenografts increased in parallel. When all the markers were compared between the biopsy and the respective 3rd generation xenograft 10 of 11 tumors showed a good correlation. Conclusions: This ongoing study provides characterization about tumoral and stromal heterogeneity in a unique orthotopic xenograft model. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: We have examined the role of VEGFC/VEGFR3 signaling in lymph node metastasis and growth of orthotopic human ME180 and SiHa cervical xenograft models following exposure to hypoxia. Our previous studies showed that growth of these tumors under conditions of cyclic hypoxia increased nodal metastasis. Methods: Mice bearing orthotopic tumors were subjected to cyclic hypoxia at 7% O2/air 10min cycles 4h/day/2weeks. Knockdown of vegfc was carried out by shRNA and inhibition of VEGFR3 was conducted by blocking antibodies for the mouse and human proteins. VEGFR3 protein expression was detected by Western blotting. Immunohistochemical staining was used to assess CA9, CD31, LYVE1 and Ki67 labeling. Gene expression was determined by real time PCR. Results: Knock down of vegfc or inhibition of VEGFR3 with blocking antibody reduced metastases under normoxic and cyclic hypoxia conditions. A reduction in lymphatics and blood vessel formation and a decrease in tumor cell proliferation was observed following vegfc knockdown and VEGFR3 inhibition. VEGFR3 expression was upregulated at the mRNA and protein levels following hypoxia. Conclusions: Collectively, our results indicate that anti-VEGFR3 antibody inhibits vegfc-induced tumor lymphangiogenesis and metastasis and that vegfc knockdown in the tumor cells causes a similar inhibitory effect on lymph node metastasis. These results suggest that the effects of vegfc/VEGFR3 on the progression of tumor cells to form lymph node metastases occur primarily under an hypoxic tumor microenvironment. [Copyright &y& Elsevier]

Purpose: To explore the relationship between oxygen-sensitive Magnetic Resonance Imaging (MRI) and oxygen measurements in prostate cancer. Methods: Nine men underwent MRI examinations followed by needle oxygen measurements of tumor bearing region within prostate gland and five men further consented to biopsy. Median pO2 and hypoxic fraction < 5 mm Hg (HP5) were derived. Biopsies were immunostained for Carbonic Anhydrase IX (CA IX), Hypoxia Inducible Factor-1 (HIF 1) and Glucose Transporter-1 (GLUT 1). Corresponding Regions-of-Interest (ROI) were delineated on T2-weighted (T2w) MRI by two observers. Median R2* was calculated for each ROI. Spearman correlation was calculated between R2* and HP5/pO2. Results: MRI quality evaluation resulted in exclusion of 4/18 ROI due to motion (n = 2) and rectal air susceptibility artifact (n = 2). Quality of remaining data was validated by concordance of R2* with T2w, indices and with secondary observer R2* (r = 0.94, p = 0.005). Correlation was observed between R2* and HP5 (r = 0.76, p = 0.02) and a trend was noted between R2* and pO2 (r = -0.66, p = 0.07). GLUT 1 and HIF 1 were expressed in all patients, and CA IX was expressed in one patient with high HP5 (77%) and low pO2 (1.4 mm Hg). Conclusions: MRI using R2* quantification is a promising tool for non-invasive imaging of prostate cancer hypoxia. [ABSTRACT FROM AUTHOR]

Purpose: Carbogen has long been under investigation as an adjuvant to radiotherapy of tumors. A major factor confounding its evaluation is its inconsistency in raising blood partial pressure of CO2 (pCO2). We investigated whether a new partial rebreathing method would provide better control of pCO2 than carbogen. Methods and materials: We compared the efficacy of each method in 10 healthy volunteers. Volunteers breathed 1.5, 3 and 5% carbogen in 5-min stages via the usual non-rebreathing circuit. All the volunteers then breathed 100% O2 through a commercial sequential gas delivery (SGD) circuit modified by attaching a reservoir to its exhalation port. Hypercarbia was induced by step reductions in oxygen flow to the SGD circuit. We monitored minute ventilation and end-tidal pCO2 (ETpCO2) as a surrogate for its arterial value. Results: Inhalation of 1.5 and 3% carbogen did not increase ETpCO2 from baseline (40 ± 1.5 mmHg); 5% carbogen increased ETpCO2 to 45 ± 1.6 mmHg (p < 0.001). With the SGD circuit, reducing O2 flow to 4.3 ± 0.7 l/min increased ETpCO2 in all subjects from 41 ± 2.0 mmHg (baseline) to 46 ± 2.1 mmHg (p < 0.001). Voluntary hyperventilation reduced ETpCO2 with 5% carbogen but not with SGD (p = 0.379). Conclusions: We confirm previous observations that carbogen inhalation does not result in a predictable rise in ETpCO2 and suggest that a precise and stable target ETpCO2 can instead be induced by simply controlling O2 flow into a modified SGD circuit. We hoped that the reliable control of pCO2 will enable studies that address first, the efficacy of raising ETpCO2 on specific tumor blood flow, and eventually, its benefit as an adjuvant to radiotherapy. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: Hypoxia and high interstitial fluid pressure (IFP) have been shown to independently predict for nodal and distant metastases, as well as survival, in patients with cervix cancer. Using data from our prospective trial, we updated a cohort of patients treated with definitive radiation alone without chemotherapy, to assess the long-term prognostic impact of these microenvironmental features. Methods: Between April 1994 and January 1999, 107 eligible patients with cervix cancer were entered into a prospective study of tumor oxygenation and IFP prior to primary radiation therapy. Oxygenation data are presented as the hypoxic proportion, defined as the percentage of pO2 readings <5mmHg (abbreviated as HP5). Patients with HP5 values >50% were considered to have hypoxic tumors. IFP is presented in mmHg, divided into high and low IFP groups by the median value. Patients ranged in age from 23 to 78 years with a mean of 53 years. The maximum tumor size ranged from 2 to 10cm, with a median diameter of 5cm. FIGO stage was IB in 28 patients, IIA in 4, IIB in 42 and IIIB in 33 patients. Twenty-two patients (21%) had evidence of pelvic lymph node involvement on staging CT abdomen/pelvis or MR pelvis. HP5 ranged from 0% to 99% with a median of 48%. IFP ranged from −3 to 48mmHg (median 19mmHg). Median follow-up was 6.7 years (range 0.9–10.6). Results: Disease-free survival (DFS) at 5 years was 50%. Five year DFS was 42% for patients with hypoxic tumors (HP5 >50%), and 58% in patients with oxygenated tumors (HR 1.01 per %, p =0.05). DFS at 5 years was 42% for patients with interstitial hypertension (IFP >19mmHg), and 63% in patients with IFP ⩽19mmHg (HR 1.05 per mmHg, p =0.001). In a multivariate analysis only tumor size (HR 1.2, p =0.009) pelvic nodal metastases (HR 3.3, p =0.0004) and IFP (HR 1.06, p =0.0005) were predictive of DFS. Because an interaction between nodal status and oxygenation was observed (p =0.03), further analysis indicated a borderline significant impact of HP5 in addition to tumor size in node negative patients (HR 1.01, p =0.06). These results were similar when local or distant relapse was used as an endpoint. Conclusions: These results confirm our initial finding of the strong independent prognostic impact of IFP for relapse and survival in patients with cervix cancer. In contrast, the independent prognostic impact of HP5 is of borderline significance and is limited to patients without imaging evidence of nodal metastases. However, these findings do not diminish the biologic significance of hypoxia, or the role of hypoxia and IFP as biomarkers of treatment response and as therapeutic targets. [Copyright &y& Elsevier]

: Background and purposeA randomized-controlled study of radical radiotherapy for cervical cancer with or without the hypoxic sensitizer, misonidazole was conducted from 1981 to 1984 to investigate its therapeutic benefit.: Patients and methodsSeventy-three patients were accrued from the Princess Margaret Hospital, and St John Regional Cancer Centre and randomized to either misonidazole (MISO, n=39) or placebo (P, n=34) in addition to radiotherapy. MISO was given orally each day 4 h prior to external beam radiation treatment (45 Gy to midplane in 20 daily fractions) at a dose of 0.45 g/m2, as well as during intra-uterine brachytherapy (40 Gy).: ResultsThe 10-year overall survival (OS) for the entire group was 46%, and the disease-free survival (DFS) was 39%. The 10-year OS for patients in the MISO arm was 45%, compared to 49% for the P arm (P=0.89). The corresponding DFS figures were 36 and 43%, respectively, (P=0.6). Ten patients (14%) developed severe late complications (grade 3 or 4). The 10-year serious late complication rate was 14% for MISO and 12% for P (P=0.51).: ConclusionsMisonidazole failed to improve the outcome of patients with cervix cancer treated with radiotherapy. [Copyright &y& Elsevier]

: PurposeTo define the minimal number of pO2 measurements, with 90% sensitivity and 90% specificity, needed to categorize cervical tumors as either hypoxic or oxic.: Methods and materialsUsing Eppendorf oxygen probe data from our ongoing prospective trial, we simulated the measurement of tumor oxygenation with a smaller number of data points in 135 patients with cervical cancer. The hypoxic proportion, defined as the percentage of pO2 values <5 mm Hg (HP5), was calculated for each tumor. Hypoxic tumors were defined as those with a median HP5 >50%, and tumors with normal oxygen levels as those with a median HP5 ≤50%. A small number of pO2 measurements were randomly selected from the Eppendorf measurements in each tumor, or per Eppendorf track, and used to define the tumor as hypoxic or oxic. The sensitivity and specificity were calculated, considering the classification as given by the complete set of Eppendorf measurements as the reference standard.: ResultsThe probability of falsely classifying the tumor decreased as the selected number of pO2 measurements per tumor increased, and at 16 measurements was approximately 10%. Adding additional measurements per tumor beyond 24 improved the ability to classify the tumor accurately only slightly. The probability of falsely classifying the tumor decreased as the pO2 measurements per track increased. At five measurements per track, the probability of falsely classifying the tumor was approximately 9%.: ConclusionApproximately 20 measurements per tumor, or five measurements per track, using the Eppendorf pO2 histograph, are sufficient to categorize cervical tumors as hypoxic or oxic. The results of this study will serve as a guide for research clinicians in the use of this and other systems in the assessment of tumor oxygenation in humans. [Copyright &y& Elsevier]

Significant heterogeneity in the tumor microenvironment of human cervical cancer patients is known to challenge treatment outcomes in this population. The current standard of care for cervical cancer patients is radiation therapy and concurrent cisplatin (CDDP) chemotherapy. Yet this treatment strategy fails to control loco-regional disease in 10–30% of patients. In order to improve the loco-regional control rate, a thermosensitive liposome formulation of CDDP (HTLC) was developed to increase local concentrations of drug in response to mild hyperthermia (HT). The HTLC formulation in combination with local HT demonstrated a significant therapeutic advantage in comparison to free drug and Lipoplatin™ in ME-180 and SiHa xenograft models of human cervical cancer, as well as in four distinct cervical patient-derived xenograft models. Differential response to HTLC + HT treatment was observed between the ME-180 and SiHa tumor models. Tumor doubling time, in vitro cell sensitivity, and tumor drug accumulation were found to be non-predictive of treatment efficacy. Rather, tumor microenvironment parameters, in particular elevated levels of both tumor hypoxia and associated stromal content, were found to serve as the overriding factors that limit drug efficacy. The prognostic value of these markers may enable stratification of cervical cancer patients for implementation of personalized medicine in the clinical setting. [ABSTRACT FROM AUTHOR]

Purpose: To measure regression of cancer of the uterine cervix during external beam radiotherapy using magnetic resonance imaging, derive radiobiologic parameters from a mathematical model of tumor regression, and compare these parameters with the pretreatment measurements of tumor hypoxia. Methods and Materials: A total of 27 eligible patients undergoing external beam radiotherapy for cervical cancer underwent weekly magnetic resonance imaging scans. The tumor volume was assessed on each of these scans and the rate of regression plotted. A radiobiologic model was formulated to simulate the effect on tumor regression of the surviving proportion of cells after 2 Gy (SP2 ), the cell clearance constant (clearance of irreparably damaged cells from the tumor [Tc ]), and accelerated repopulation. Nonlinear regression analysis was used to fit the radiobiologic model to the magnetic resonance imaging-derived tumor volumes and to derive the estimates of SP2 and Tc for each patient. These were compared to the pretreatment hypoxia measurements. Results: The initial tumor volume was 8–209 cm3. The relative reduction in volume during treatment was 0.02–0.79. The simulations using representative values of the independent biologic variables derived from published data showed SP2 and Tc to strongly influence the shape of the volume–response curves. Nonlinear regression analysis yielded a median SP2 of 0.71 and median Tc of 10 days. Tumors with a high SP2 >0.71 were significantly more hypoxic at diagnosis (p = 0.02). Conclusion: The results of our study have shown that cervical cancer regresses during external beam radiotherapy, although marked variability is present among patients and is influenced by underlying biologic processes, including cellular sensitivity to radiotherapy and proliferation. Better understanding of the biologic mechanisms might facilitate novel adaptive treatment strategies in future studies. [Copyright &y& Elsevier]

Purpose: The non–protein sulfydryls (NPSH) glutathione and cysteine are able to effect chemical repair of radiation-induced DNA damage, particularly under hypoxic conditions, and are implicated in radioresistance. The levels of NPSH in the nucleus are predicted to be more important than those in cytoplasm. We, therefore, investigated the relation between nuclear NPSH and the clinical outcome of radical radiotherapy (RT).Methods and materials: A fluorescence image analysis technique to measure nuclear NPSH was developed, based on the SH-reactive probe 1(4-chloromercuryphenyl-azo-2-naphthol) and the DNA dye 4,6-diamidino-2-phenylindole. This was used to measure nuclear and tissue NPSH levels in biopsies obtained from 58 patients with locally advanced uterine cervical carcinoma, treated with radical RT.Results: An approximately twofold range in the nuclear and tissue NPSH levels between individual tumors was found, although the intratumoral heterogeneity was much smaller. Nuclear and tissue NPSH values correlated closely in all cases. No statistically significant associations were noted between NPSH levels and tumor size, stage, or tumor hypoxia as determined at the time of biopsy using an Eppendorf po2 probe. The response to RT and patient survival did not correlate with tumor NPSH.Conclusion: These results did not support the existence of an independently regulated nuclear pool of NPSH and showed that tissue and nuclear NPSH are not predictive of the outcome of patients with locally advanced cervical carcinomas treated with RT. [Copyright &y& Elsevier]

Purpose: To investigate the relations between hypoxia-inducible factor-1 (HIF-1), tumor oxygenation, and clinical correlates in patients with locally advanced carcinoma of the uterine cervix.Methods and Materials: Biopsies from 42 patients with invasive cervical carcinoma and previous polarographic O2 measurements were assessed for the expression of HIF-1α using digitized microscopic imaging and analysis.Results: The HIF-1α expression levels ranged from <0.1% to 10.7% of the total tumor area; the positive staining was localized exclusively to the nuclei. Three distinct arrangement patterns of HIF-1α-positive cells in relation to blood vessels were identified using spatial image mapping: (1) most HIF-1α-positive cells were located within the typical oxygen diffusion distance in tissue (≤150 μm to the nearest blood vessel); (2) most HIF-1α-positive cells were located in the vicinity (≤60 μm) of the blood vessels; and (3) no apparent spatial relationship was found between HIF-1α-positive cells and blood vessels. A statistically significant association was found between HIF-1α expression and tumor oxygenation (Spearman correlation coefficient = 0.4, p <0.01), as determined with the Eppendorf pO2 histograph. No correlation was found between the level of HIF-1α expression and patient outcome, using disease-free survival as the end point.Conclusion: Our results suggest that HIF-1α expression may represent a useful biologic marker for hypoxia in uterine cervical cancer. [Copyright &y& Elsevier]