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Biomedical subjects

Samuel Hellman

Publications and source records attributed to Samuel Hellman.

At least 19 recordsLinked to original sources
PubMed2005

Hormone therapy and radiotherapy for early prostate cancer: a utility-adjusted number needed to treat (NNT) analysis.

PURPOSE: To quantify, using the number needed to treat (NNT) methodology, the benefit of short-term (< or =6 months) hormone therapy adjuvant to radiotherapy in the group of patients with early (clinical stage T1-T2c) prostate cancer. METHODS AND MATERIALS: The absolute biochemical control benefit for the use of hormones adjuvant to radiotherapy in early-stage disease was determined by literature review. A model was developed to estimate the utility-adjusted survival detriment due to the side effects of hormone therapy. The NNTs before and after the incorporation of hormone sequelae were computed; the sign and magnitude of the NNTs were used to gauge the effect of the hormones. RESULTS: The absolute NNT analysis, based on summarizing the results of 8 reports including a total of 3652 patients, demonstrated an advantage to the addition of hormones for the general early-stage prostate cancer population as well as for all prognostic groups. After adjustment for hormone-induced functional loss, the advantage of hormones remained considerable in the high- and intermediate-risk groups, with the utility-adjusted NNT becoming weakened in the low-risk group when the utility compromise from complications of hormones was assumed to be considerable. CONCLUSIONS: Short-term hormone therapy seems to be beneficial for selected early-stage prostate cancer patients. The advantage seems to be greatest in the intermediate- and high-risk groups; with current follow-up, the side effects of hormones may outweigh their benefit in certain clinical situations in the favorable group. The present investigation demonstrates the significant role of the NNT technique for oncologic and radiotherapeutic management decisions when treatment complications need to be considered and balanced with the beneficial effects of the treatment.

Androgen Antagonists↗
PubMed2005

Evolving paradigms and perceptions of cancer.

The word cancer produces widely differing perceptions between the general public, and the scientific and medical communities. These different ideas lead to very diverse understandings of the disease. The paradigms affect both the focus and design of research and also impact upon patient care. The cultural perception is very pessimistic: a relentless, incurable, extremely painful disease, the treatment of which is conceived as difficult, with little chance of a simple cure. Within the medical and scientific communities, however, there are a number of quite different views of the disease. Both the orderly extension of disease described by Halsted, and the systemic nature of cancer even when it appears to be localized, are perceptions within the professional community. The promise of a 'magic bullet' is in sharp contrast to the incremental advances seen in clinical oncology. What is needed is a clear recognition of how these varying perceptions of cancer affect and limit communication among the cancer-related disciplines as well as between these disciplines and the public. Both professionals and the general public should consider cancer as a group of diseases for which cure is related to tumor type, stage and available treatment.

Attitude of Health Personnel↗
PubMed2004

The natural history of breast carcinoma in the elderly: implications for screening and treatment.

BACKGROUND: The authors evaluated the two indicators of metastatic proclivity (namely, virulence [V; the rate of appearance of distant metastases] and metastagenicity [M; the ultimate likelihood of developing distant metastases]) of breast carcinoma in elderly women. The authors then compared these characteristics with the corresponding characteristics in a cohort of younger women to determine whether breast carcinoma was more indolent in women age > 70 years, as is commonly believed in the medical community. METHODS: The authors examined 2136 women who underwent mastectomy without adjuvant systemic therapy at The University of Chicago Hospitals (Chicago, IL) between 1927 and 1987. The median follow-up period was 12.3 years. Distant disease-free survival (DDFS) was determined for women who did not receive systemic therapy. V and M were obtained from log-linear plots of DDFS. RESULTS: No significant difference in tumor size at presentation was observed among women age < 40 years, women ages 40-70 years, and women age > 70 years (P = 0.86), whereas significantly fewer women age > 70 years presented with positive lymph nodes compared with younger women (P = 0.05). In women with negative lymph node status, there was a higher DDFS rate among patients ages 40-70 years (81% at 10 years) compared with patients age > 70 years (65% at 10 years; P = 0.018). There was no significant age-related difference among women with lymph node-positive disease (P = 0.2). For example, the 10-year DDFS rate for women ages 40-70 years was 33%, compared with 38% for women age > 70 years. Among those with lymph node-negative disease, V was 3% per year for women ages 40-70 years as well as women age > 70 years. Among women with lymph node-negative disease, M was 0.20 for patients ages 40-70 years and 0.35 for patients age > 70 years. In women with positive lymph node status, both V (11% per year vs. 10% per year) and M (0.70 vs. 0.65) were similar in both age groups. CONCLUSIONS: Fewer women age > 70 years had lymph node involvement at presentation. However, when this finding was taken into account, the authors found no evidence that breast carcinoma was more indolent in women age > 70 years. These results support the use of similar diagnostic and therapeutic efforts for elderly women and younger women, with modification for elderly women based only on comorbidity.

Adult↗
PubMed2004

Chemoinducible gene therapy: a strategy to enhance doxorubicin antitumor activity.

A replication-defective adenoviral vector, Ad.Egr-TNF.11D, was engineered by ligating the CArG (CC(A/T)6GG) elements of the Egr-1 gene promoter upstream to a cDNA encoding human tumor necrosis factor-alpha. We report here that Ad.Egr-TNF.11D is activated by the clinically important anticancer agents cisplatin, cyclophosphamide, doxorubicin, 5-fluorouracil, gemcitabine, and paclitaxel. N-acetylcysteine, a free radical scavenger, blocked induction of tumor necrosis factor-alpha by anticancer agents, supporting a role for reactive oxygen intermediates in activation of the CArG sequences. Importantly, resistance of PC-3 human prostate carcinoma and PROb rat colon carcinoma tumors to doxorubicin in vivo was reversed by combining doxorubicin with Ad.Egr-TNF and resulted in significant antitumor effects. Treatment with Ad.Egr-TNF.11D has been associated with inhibition of tumor angiogenesis. In this context, a significant decrease in tumor microvessel density was observed following combined treatment with doxorubicin and Ad.Egr-TNF.11D as compared with either agent alone. These data show that Ad.Egr-TNF.11D is activated by diverse anticancer drugs.

Acetylcysteine↗
PubMed2004

Analysis of further disease progression in metastatic non-small cell lung cancer: implications for locoregional treatment.

To determine whether in the natural history of metastatic non-small cell lung cancer (NSCLC) a time interval exists when metastases are limited in number and/or destination organs. Thirty-eight stage IIIB (pleural effusion)/IV NSCLC patients were treated on a phase II trial of oxaliplatin and paclitaxel. Patients' charts were reviewed and all sites of disease at initial presentation and at subsequent follow-ups were recorded, including the number of organs involved and the number of individual metastatic sites. At presentation, 74% of patients had metastases confined to one or two organs (including the lung primary). Fifty percent had < or =3 metastatic sites in addition to the lung primary. At last follow-up, 17 patients developed new lesions, 14 in a new organ and 3 in a previously involved organ. Nineteen (50%) had stable (n=12) or progressive (n=7) disease in initially involved sites without developing any new metastatic tumors. Among the 17 patients who presented with < or =4 metastatic sites and no pleural effusion, 11 (65%) had stable or progressive disease in initially involved sites without developing new metastases. These results suggest that a subset of patients who present with metastatic NSCLC may not have widely disseminated disease and that some form of local treatment combined with systemic therapy might be beneficial in these patients. Our data support the feasibility of a clinical trial that incorporates local therapies to sterilize metastases in patients with NSCLC.

Adult↗
PubMed2003

Hormone therapy adjuvant to external beam radiotherapy for locally advanced prostate carcinoma: a complication-adjusted number-needed-to-treat analysis.

BACKGROUND: Hormone therapy commonly is used to treat metastatic, locally advanced, and localized prostate carcinoma. The objective of the current investigation was to determine, using the number-needed-to-treat (NNT) method, the effect of using hormone therapy to treat locally advanced disease, with consideration given to both the complications and the known advantages associated with hormone therapy. METHODS: A literature review was performed to determine 1) the absolute benefit, based on available clinical endpoints, associated with the addition of hormone therapy to external beam radiotherapy for locally advanced prostate carcinoma; 2) the incidence of side effects of short-term and long-term hormone therapy; and 3) the stepwise progression from biochemical failure to death. A model was constructed to estimate the complication/utility-adjusted survival detriment resulting from the side effects of short-term (</= 6 months) and long-term (> 6 months) hormone therapy, and the absolute/unadjusted and complication-adjusted NNTs for the addition of short-term and long-term hormone therapy were computed. In all cases, the magnitudes and signs of the NNTs obtained were used to gauge the effect of hormone therapy. RESULTS: The unadjusted NNTs were positive and in most cases had relatively small magnitudes (the greater the NNT, the smaller the benefit) for both short-term and long-term hormone therapy; these results were expected, and they suggested that there is a strong benefit associated with the use of hormones adjuvant to radiotherapy for locally advanced disease. Adjusted NNTs remained positive and had relatively small magnitudes even after the introduction into the analysis of complications of short-term and long-term hormone therapy. This finding, although weak with respect to the effect of short-term hormone therapy on cause-specific survival, remained robust over the range of values for utility impairment expected from short-term and long-term hormone therapy. CONCLUSIONS: The benefits of short-term and long-term hormone therapy for locally advanced prostate carcinoma appear to be significant and to outweigh the associated side effects. Long-term therapy appears to be better than short-term therapy in terms of virtually all endpoints studied, even when the increased incidence of side effects is considered. The current investigation was successful in the use of the complication-adjusted NNT method for oncologic and radiotherapeutic scenarios in which the results of randomized trials could be summarized, adjusted for treatment toxicity, and individualized to a given patient.

Antineoplastic Agents, Hormonal↗
PubMed2003

Early prostate cancer: clinical decision-making.

Prostate cancer is one of the most common malignant diseases for which health-care intervention is sought worldwide, and in many developed countries it is the most common. Some patients with early-stage prostate cancer, especially those who are elderly and have comorbidities, can be observed without treatment. Surgery (radical prostatectomy) and radiotherapy (external-beam radiotherapy, brachytherapy, or both) are the most widely accepted curative options for patients with early-stage disease who need intervention. All these local treatments have been refined, resulting in comparable cure rates; however, they all have different side-effect profiles. Adjuvant systemic treatments (hormones or chemotherapy), which are effective for advanced-stage disease, might have a greater role in early-stage disease. Selecting the best option for individuals from the available options is challenging--the decision on whether and how to treat is based on many disease and patient factors. Here, we review the major treatment options, discuss their relative advantages and disadvantages, and provide a general approach to management of patients with early-stage prostate cancer.

Aged↗
PubMed2003

Sentinel lymph node versus axillary lymph node dissection for early-stage breast carcinoma: a comparison using a utility-adjusted number needed to treat analysis.

BACKGROUND: The current study was performed to compare the value of sentinel lymph node dissection (SND) and axillary lymph node dissection (AND) in improving the utility-adjusted survival for early-stage breast carcinoma patients. METHODS: A number needed to treat (NNT) analysis was used to compare SND with AND. In the NNT equation, 1/(S(SND) - S(AND)), S is the 5-year utility-adjusted survival. A literature review was performed to estimate 1) the prevalence of axillary lymph node disease for early-stage breast carcinoma, 2) the sensitivity and specificity of SND and AND, 3) the 5-year overall survival as a function of axillary lymph node involvement, 4) the risk of arm lymphedema as a function of the intervention performed, and 5) the utility correction (Uc; impairment of quality of life) for arm lymphedema. RESULTS: The NNT method of analysis favored SND over nearly the entire range of parameters with a sign change to a negative value occurring only as Uc becomes very close to unity. This suggests the superiority of the SND approach. Only when there is minimal loss of utility does AND become favored and then only minimally. CONCLUSIONS: Compared with AND, SND improves the utility-adjusted survival in patients with early-stage breast carcinoma. This finding is quite robust and was found to remain constant over a range of values for utility and lymph node prevalence.

Breast Neoplasms↗
PubMed2003

Receiver operating characteristic analysis: a general tool for DNA array data filtration and performance estimation.

A critical step for DNA array analysis is data filtration, which can reduce thousands of detected signals to limited sets of genes. Commonly accepted rules for such filtration are still absent. We present a rational approach, based on thresholding of intensities with cutoff levels that are estimated by receiver operating characteristic (ROC) analysis. The technique compares test results with known distributions of positive and negative signals. We apply the method to Atlas cDNA arrays, GeneFilters, and Affymetrix GeneChip. ROC analysis demonstrates similarities in the distribution of false and true positive data for these different systems. We illustrate the estimation of an optimal cutoff level for intensity-based filtration, providing the highest ratio of true to false signals. For GeneChip arrays, we derived filtration thresholds consistent with the reported data based on replicate hybridizations. Intensity-based filtration optimized with ROC combined with other types of filtration (for example, based on significances of differences and/or ratios), should improve DNA array analysis. ROC methodology is also demonstrated for comparison of the performance of different types of arrays, imagers, and analysis software.

Data Interpretation, Statistical↗
PubMed2002

Radiation-induced tumour necrosis factor-alpha expression: clinical application of transcriptional and physical targeting of gene therapy.

Promising data are emerging on a new anticancer agent, Ad.EGR-TNF, an adenoviral vector, which contains radio-inducible DNA sequences from the early growth response (EGR1) gene promoter and cDNA for the gene encoding human tumour necrosis factor-alpha. Ad.EGR-TNF combines the well-documented broad-spectrum anticancer activity of TNFalpha with the proven clinical usefulness of radiotherapy. Systemic delivery of the TNFalpha protein has had limited success clinically because of severe dose-limiting toxic effects. This limitation has been overcome by the use of a gene delivery approach, combined with a radiation-inducible promoter to express the TNFalpha protein in the irradiated tumour tissue. Preclinical and early phase I clinical testing indicates that effective concentrations of TNFalpha can be delivered to the tumour site without significant systemic exposure or toxic effects. The combination of radiation and TNFalpha gene delivery has produced striking antitumour effects in model systems in animals. In the clinical setting, potent anticancer activity has been observed with a high rate of complete and partial objective tumour responses. A novel mechanism of destruction of the tumour vasculature seems to be central to this distinct antitumour activity. This review summarises the rationale, mechanistic basis, preclinical data, and preliminary clinical findings for this new treatment model.

Clinical Trials as Topic↗