Biomedical subjects

Anthony W Fyles

Publications and source records attributed to Anthony W Fyles.

5 recordsLinked to original sources

PubMed2006

Hypoxia: importance in tumor biology, noninvasive measurement by imaging, and value of its measurement in the management of cancer therapy.

PURPOSE: The Cancer Imaging Program of the National Cancer Institute convened a workshop to assess the current status of hypoxia imaging, to assess what is known about the biology of hypoxia as it relates to cancer and cancer therapy, and to define clinical scenarios in which in vivo hypoxia imaging could prove valuable. RESULTS: Hypoxia, or low oxygenation, has emerged as an important factor in tumor biology and response to cancer treatment. It has been correlated with angiogenesis, tumor aggressiveness, local recurrence, and metastasis, and it appears to be a prognostic factor for several cancers, including those of the cervix, head and neck, prostate, pancreas, and brain. The relationship between tumor oxygenation and response to radiation therapy has been well established, but hypoxia also affects and is affected by some chemotherapeutic agents. Although hypoxia is an important aspect of tumor physiology and response to treatment, the lack of simple and efficient methods to measure and image oxygenation hampers further understanding and limits their prognostic usefulness. There is no gold standard for measuring hypoxia; Eppendorf measurement of pO(2) has been used, but this method is invasive. Recent studies have focused on molecular markers of hypoxia, such as hypoxia inducible factor 1 (HIF-1) and carbonic anhydrase isozyme IX (CA-IX), and on developing noninvasive imaging techniques. CONCLUSIONS: This workshop yielded recommendations on using hypoxia measurement to identify patients who would respond best to radiation therapy, which would improve treatment planning. This represents a narrow focus, as hypoxia measurement might also prove useful in drug development and in increasing our understanding of tumor biology.

Antigens, Neoplasm↗

PubMed2004

Tamoxifen with or without breast irradiation in women 50 years of age or older with early breast cancer.

BACKGROUND: We determined the effect of breast irradiation plus tamoxifen on disease-free survival and local relapse in women 50 years of age or older who had T1 or T2 node-negative breast cancer. METHODS: Between December 1992 and June 2000, 769 women with early breast cancer (tumor diameter, 5 cm or less) were randomly assigned to receive breast irradiation plus tamoxifen (386 women) or tamoxifen alone (383 women). The median follow-up was 5.6 years. RESULTS: The rate of local relapse at five years was 7.7 percent in the tamoxifen group and 0.6 percent in the group given tamoxifen plus irradiation (hazard ratio, 8.3; 95 percent confidence interval, 3.3 to 21.2; P<0.001), with corresponding five-year disease-free survival rates of 84 percent and 91 percent (P=0.004). A planned subgroup analysis of 611 women with T1, receptor-positive tumors indicated a benefit from radiotherapy (five-year rates of local relapse, 0.4 percent with tamoxifen plus radiotherapy and 5.9 percent with tamoxifen alone; P<0.001). Overall, there was a significant difference in the rate of axillary relapse at five years (2.5 percent in the tamoxifen group and 0.5 percent in the group given tamoxifen plus irradiation, P=0.049), but no significant difference in the rates of distant relapse or overall survival. CONCLUSIONS: As compared with tamoxifen alone, radiotherapy plus tamoxifen significantly reduces the risk of breast and axillary recurrence after lumpectomy in women with small, node-negative, hormone-receptor-positive breast cancers.

Aged↗

PubMed2003

Estimating hypoxic status in human tumors: a simulation using Eppendorf oxygen probe data in cervical cancer patients.

PURPOSE: To define the minimal number of pO(2) measurements, with 90% sensitivity and 90% specificity, needed to categorize cervical tumors as either hypoxic or oxic. METHODS AND MATERIALS: Using 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 pO(2) 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 < or =50%. A small number of pO(2) 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. RESULTS: The probability of falsely classifying the tumor decreased as the selected number of pO(2) 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 pO(2) measurements per track increased. At five measurements per track, the probability of falsely classifying the tumor was approximately 9%. CONCLUSION: Approximately 20 measurements per tumor, or five measurements per track, using the Eppendorf pO(2) 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.

Adenocarcinoma↗

PubMed2003

Prospective comparison of breast pain in patients participating in a randomized trial of breast-conserving surgery and tamoxifen with or without radiotherapy.

PURPOSE: To determine whether breast pain affects quality of life (QOL) after breast-conserving surgery and tamoxifen (TAM) with or without adjuvant breast radiotherapy (RT). METHODS AND MATERIALS: A randomized clinical trial was carried out at the Princess Margaret Hospital between 1992 and 2000 to evaluate the need for breast RT in addition to TAM in women >or=50 years treated with breast-conserving surgery for T1-T2N0 breast cancer. A companion study to assess breast pain was carried out during the last 2 years of the randomized clinical trial. The short-form McGill Pain Questionnaire (SF-MPQ), the European Organization for Research and Treatment of Cancer (EORTC) QOL (QLQ-C30) and EORTC breast cancer module (QLQ-BR23) questionnaires were completed by patients within 1 week of randomization in the randomized clinical trial (baseline) and at 3, 6, and 12 months. RESULTS: Eighty-six patients participated in the breast pain study; 41 received RT plus TAM and 45 received TAM alone. The median age was 70 years (range 51-80). The baseline pain and QOL scores were similar for the two groups. No significant difference was found between the two groups for each scale of the QLQ-C30 and QLQ-BR23 questionnaires at 3, 6, or 12 months (p >0.100), except that at 12 months, the score for role function (QLQ-C30) was higher in the RT plus TAM group than in the RT-only group (p = 0.02). At 3 months, the difference between the mean scores for the SF-MPQ was 0.553 (p = 0.47). At 12 months, the pain scores had decreased in both groups; the difference was 0.199 (p = 0.71). The number of breast operations or surgical complications did not correlate with breast pain in either group. Acute RT toxicity scores did not correlate with breast pain or QOL scores at 12 months. CONCLUSION: These results suggest that breast RT does not significantly contribute to breast pain or adversely impact the QOL up to 12 months after treatment in postmenopausal patients with node-negative breast cancer who take TAM.

Aged↗

PubMed2002

Expression of hypoxia-inducible factor-1alpha in cervical carcinomas: correlation with tumor oxygenation.

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-1alpha using digitized microscopic imaging and analysis. RESULTS: The HIF-1alpha 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-1alpha-positive cells in relation to blood vessels were identified using spatial image mapping: (1) most HIF-1alpha-positive cells were located within the typical oxygen diffusion distance in tissue (< or =150 microm to the nearest blood vessel); (2) most HIF-1alpha-positive cells were located in the vicinity (< or =60 microm) of the blood vessels; and (3) no apparent spatial relationship was found between HIF-1alpha-positive cells and blood vessels. A statistically significant association was found between HIF-1alpha 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-1alpha expression and patient outcome, using disease-free survival as the end point. CONCLUSION: Our results suggest that HIF-1alpha expression may represent a useful biologic marker for hypoxia in uterine cervical cancer.

Aged↗