Biomedical subjects
A J Coldman
Publications and source records attributed to A J Coldman.
Anatomic distribution of acquired melanocytic nevi in white children. A comparison with melanoma: the Vancouver Mole Study.
The presence of acquired benign nevi is a risk factor for cutaneous melanoma, yet relatively little is known about the etiology of nevi. We have conducted a study of the prevalence of melanocytic nevi among 1146 white Vancouver (Canada) schoolchildren aged 6 to 18 years. Numbers of nevi per square meter of body surface area increase with age in children of both sexes. Male adolescents have more nevi than female adolescents on the head and neck as well as on the trunk, while prevalence in females is higher on the upper and lower limbs. This distribution parallels that of cutaneous melanoma in British Columbia adults. Nevi are more common in children on intermittently exposed body sites than on constantly or minimally sun-exposed sites. This suggests that exposure to strong intermittent sunlight in childhood (a risk factor for cutaneous melanoma) may also be important in the etiology of acquired benign nevi.
Suntan, sunburn, and pigmentation factors and the frequency of acquired melanocytic nevi in children. Similarities to melanoma: the Vancouver Mole Study.
The association between prevalence of benign melanocytic nevi and a number of skin cancer risk factors was examined among 913 white Vancouver (Canada) school children aged 6 to 18 years. Subjects with light skin, with a propensity to burn rather than tan in the sun, and with numerous or severe sunburns in the previous 5 years had significantly higher nevus counts than individuals without these characteristics. Subjects who acquired deeper tans tended to have fewer nevi than those who did not tan. Finally, children who freckled had higher nevus counts than those who did not freckle. These findings in children are similar to those seen in studies of malignant melanoma among adults and suggest that strategies to reduce melanoma incidence should begin with young children.
Cervical intraepithelial neoplasia in female prisoners in British Columbia.
The annual incidence rates of cervical intraepithelial neoplasia (CIN), grades I to III, from 1975 to 1983 among 2440 prisoners in British Columbia for whom a history of screening by means of the Papanicolaou test was available were two to three times higher than the expected rates in the general female population of British Columbia. The rates among the prisoners from 1970 to 1984, although small, increased with a trend similar to that in the general population. Despite increases in the general population we conclude that prisoners are still at high risk for CIN.
Influence of estrogen receptor status on dietary risk factors for breast cancer.
It has been suggested that the relation between diet and breast cancer may depend on estrogen receptor (ER) status. We examined the responses to a self-administered questionnaire on frequency of consumption of various foods by 493 women with breast cancer (160 with ER-negative tumours and 333 with ER-positive tumours) and 527 controls whose menopausal status was known. Analysis of the reported consumption of foods selected for their fat or carotene content showed no clear distinction in dietary factors between the ER-negative and ER-positive groups. Frequent consumption of meat fats generally increased the risk of both ER-negative and ER-positive tumours; there were no clear trends in risk associated with vegetable consumption for either ER group. Fish was the only item affecting the risk for ER-negative and ER-positive tumours differently, frequent consumption reducing the risk for the former (p = 0.02). The results do not support the hypothesis that ER status influences the relation between dietary fat consumption and risk of breast cancer.
The classification of ethnic status using name information.
Methodology is developed to classify ethnic status by name using a simple probabilistic model. This method involves the consideration of four rules which may be used to classify individuals using three name components (first, middle and last names). In order to do this, conditional probabilities of ethnic status are estimated from a sample in which the ethnic status is known. Using a split sample technique the sensitivity and specificity of this methodology were examined in a data set of death registrations. Each of the classification rules performed well on the data from which they were constructed but were not as efficient when applied to another population. Nevertheless a model (linear), in which the sum of the conditional probabilities of each home component is used, achieved a sensitivity and specificity of 97% and 100% respectively in males and 89% and 100% in females.
A mathematical and computer-based model of alternating chemotherapy and radiation therapy in experimental neoplasms.
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Economics of screening for cervical cancer.
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The prognostic significance of psychosocial factors in women with breast cancer.
One hundred and thirty three recently diagnosed breast cancer patients completed a self-administered questionnaire which measured 16 psychosocial variables. After 4 years, three variables (expressive activities at home, extroversion, low anger) were significant prognostic factors for overall survival independent of clinical and other psychosocial factors; likewise three variables (expressive activities at home, expressive activities away from home, low cognitive disturbance) were significant independent prognostic factors for disease-free survival. These findings support the prognostic importance of the social emotional network.
Impact of dose-intense chemotherapy on the development of permanent drug resistance.
Using a somatic mutation theory for drug resistance, dose intense regimens are shown to be superior in increasing the likelihood of no doubly resistant cells and in curing the tumor. Consideration of this model suggests that dose intensity of early chemotherapy cycles should be calculated separately and correlated with treatment outcome.
Theoretical considerations regarding the early use of adjuvant chemotherapy.
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Factors affecting the development of permanent drug resistance and its impact upon neoadjuvant chemotherapy.
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A stochastic model for the origin and treatment of tumors containing drug-resistant cells.
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Relationship between risk factors for breast cancer and hormonal status.
A total of 512 breast cancer patients and 540 controls were compared to examine the risk factors for different categories of breast cancer as defined by age, menopausal status and estrogen receptor (ER) tumor status. Significant differences were found by menopausal status, for age at first birth and age at menarche for all women, and for age at first birth and family history for women between 45 and 54 years old. No significant differences were found with ER status alone; however there was a significant difference between ER status and body weight in premenopausal women; the above significant differences with menopausal status were not found when stratified by ER tumour status. These findings support the hypothesis for aetiological differences for pre- and postmenopausal breast cancer and suggest that ER tumour status may influence the risk associated with body weight.
Re: "Overweight and changes in weight throughout adult life in breast cancer etiology: a case-control study".
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Analyzing the patterns of treatment failure.
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Application of theoretical models to chemotherapy protocol design.
The somatic mutation model of cancer chemotherapy predicts that under certain conditions some sequences of chemotherapy drug administration will be superior to others. Alternation between two non-cross-resistant combinations that are equivalent in effectiveness is one such sequence. This method was utilized in a number of clinical trials based primarily on intuitive perceptions on how treatment failure due to drug resistance can be minimized. A survey of a number of recently published trials employing some form of alternating chemotherapy indicates that a majority of them suggested an advantage to this approach compared to sequential therapy, although in most studies this benefit was small. Most of the studies, whether or not supportive of the concept of alternating therapy, could not be considered a fair test of the theory. Reference to theoretical models of chemotherapeutic action may provide assistance in devising clinical trials that will rigorously test the concept of alternating chemotherapy to see to what extent this technique will improve treatment results in selected neoplasms.
Study of benign breast disease in a population screened for breast cancer.
We are conducting a study to determine whether risk factors associated with specific pathologic subtypes of benign breast disease (BBD) are similar to those for breast cancer and to evaluate the relationship between clinical and mammographic features of BBD. All women participating in the Canadian National Study of Breast Cancer Screening in Vancouver, B.C., Canada (expected 10,000) are invited to complete a questionnaire designed to gather clinical and epidemiologic information on BBD. Preliminary analysis of the first 736 participants indicates that breast pain and/or tenderness is a significant problem which in its severe from is distressing, anxiety provoking, and adversely affecting quality of life. Breast pain and tenderness is also associated with an increased frequency of clinical signs of BBD and of dense mammographic patterns.