Biomedical subjects

W Hanna

Publications and source records attributed to W Hanna.

76 records · Page 5Linked to original sources

PubMedDate not supplied

Alternative multivariate modelling for time to local recurrence for breast cancer patients receiving a lumpectomy alone.

Certain prognostic factors (patient and/or tumour characteristics) may be associated with low (or high) risk for local recurrence. Patients with these characteristics could be candidates for less (or more) adjuvant therapy or a less (or more) aggressive surgical approach. However, the assessment of many factors can be problematic with the standard multivariate technique-a Cox proportional hazards model and step-wise regression. We compared the results obtained when using a Cox model with those from four alternative models (exponential, Weibull, log logistic and log Normal) in step-wise and all subset regressions. Between 1977 and 1986, 293 primary invasive breast cancer patients were treated at the Henrietta Banting Breast Centre with a lumpectomy with or without an axillary dissection, and with no postoperative adjuvant therapy. The variables considered were age, lymph node status, tumour size, estrogen receptor (ER), progesterone receptor (PgR), histologic grade, nuclear grade, carcinoma in situ (CIS), amount of CIS, and presence of tumour emboli. With follow-up to 1991, nodal status was not found to be included in the step-wise Cox model, although it was in the step-wise exponential, Weibull and log Normal models, and in the best all subset models for all model types. The variables tumour emboli, ER, age, CIS and nodal status were consistently included in the best all subset regressions, regardless of model type. In the 1993 follow-up, the variables in the step-wise Cox model were tumour emboli, ER, age, CIS and nodal status. The multivariate consideration of all possible subsets of regression variables led to an earlier indication of the importance of nodal status, while the data strongly supported accelerated failure time models over the Cox model.

Analysis of Variance↗

PubMedDate not supplied

Breast cancer and organochlorines: a marker for susceptibility?

The incidence of breast cancer is increasing and despite extensive research efforts, the etiology of this disease is largely unknown. Most women exhibit no known risk factors except for their age and sex. It has recently been postulated that the increased breast cancer incidence might be attributed to exposure to environmental carcinogens such as the organochlorine compounds. In this article, the scientific literature with respect to this possibility is reviewed and alternative hypotheses, which may in part explain the possible role of organochlorine compounds in the etiology of breast cancer, are presented.

Biomarkers, Tumor↗

PubMedDate not supplied

[Essential functions of public health: emerging topic in health care reform].

In the Americas, health sector reforms are facing the challenge of strengthening the steering and leadership role of health authorities. An important part of that role consists of fulfilling the essential public health functions (EPHFs) that are incumbent on all levels of government. For that, it's crucial to improve public health practice, as well as the instruments used to assess the current state of public health practice and the areas where it needs to be strengthened. For that purpose, the Pan American Health Organization has started an initiative called "Public Health in the Americas," with the objective of defining and measuring EPHFs, as a way of improving public health practice and strengthening the leadership provided by health authorities at all levels of government. This article summarizes conceptual and methodological aspects of defining and measuring EPHFs. The article also analyzes the implications that measuring performance on these public health roles, responsibilities, and activities would have for improving public health practice in the Americas.

Americas↗

PubMedDate not supplied

The ultrastructure of metastatic adenocarcinoma in serous fluids. An aid in identification of the primary site of the neoplasm.

Identification of the primary sites of metastatic adenocarcinomas is a diagnostic problem, particularly in cases of occult primary neoplasms. We studied the ultrastructural morphology of 16 metastatic adenocarcinomas that presented as effusions to establish organ-specific features that would characterize adenocarcinomas from various sites. The nine cases in which the site of the primary carcinoma was known included seven derived from the breast, one from the ovary and one from the colon. The primary site was unknown in seven cases at the time of presentation. After investigations, the primary site became known in five cases (lung, colon and appendix, one case each, and the ovary in two cases). Ultrastructurally diagnostic features could be detected in gastrointestinal, ovarian, bronchioloalveolar-cell and breast carcinomas. In gastrointestinal carcinomas, the presence of short microvilli with long rootlets was specific for the group. The lamellar inclusions of type II pneumocytes were diagnostic of bronchioloalveolar-cell carcinoma. The microvilli in ovarian carcinomas were long, slender and bushy, as in mesotheliomas; however, the cells lacked the perinuclear condensation of tonofilaments seen in the latter. Breast carcinomas were associated with numerous intracytoplasmic lumina, electron-dense granules and aggregates of small vesicular bodies. We conclude that ultrastructural examination of adenocarcinomas in serious fluids can help to identify the primary site of certain neoplasms or at least shorten the list of possibilities. This may reduce costs and minimize the discomfort patients have to undergo by curtailing extensive invasive investigations in search of unknown primary neoplasms.

Adenocarcinoma↗