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Biomedical subjects

R K Severson

Publications and source records attributed to R K Severson.

At least 55 records · Page 3Linked to original sources
PubMed1994

The influence of subsequent neoplasms on incidence trends in childhood cancer.

The purpose of this analysis was to evaluate to what extent subsequent malignant neoplasms account for the increasing rates of cancer occurrence among children. Data from the population-based Surveillance, Epidemiology, and End Results program were used to calculate age-standardized annual incidence rates from 1974-1989 for 10 common cancers among children 14 years of age or younger. Mean rates and linear trends were evaluated using least squares regression, first for all neoplasms and then excluding subsequent neoplasms, to determine if the removal of subsequent neoplasms would attenuate increasing trends. Increasing annual incidence rates were found for all childhood cancers combined, acute lymphoid leukemia, and brain tumors, but not for other cancer types. Excluding subsequent neoplasms from the analysis had a negligible effect on the trends we observed. Although it remains largely undetermined why childhood cancer incidence rates are increasing in the United States, this study presents evidence that subsequent primary neoplasms do not substantively contribute to these observed trends.

Adolescent↗
PubMed1993

Trends in the incidence of soft tissue sarcomas in the United States from 1973 through 1987.

BACKGROUND: Soft tissue sarcomas (STS) comprise a relatively rare group of malignant tumors of the connective tissues. It is estimated that approximately 6000 cases of STS will occur in the United States in 1993. Concerns have been raised in the clinical community that the incidence of STS may be increasing. METHODS: Incidence rates of STS were obtained from the Surveillance, Epidemiology, and End Results program. Cases were restricted by histologic classification to malignant tumors determined a priori to be STS by a pathologist specializing in diseases of soft tissue. Age-, sex- and race-specific rates also were examined. RESULTS: A total of 18,525 newly diagnosed cases of STS were identified for the period 1973 through 1987 in the United States. There was a marked increase in the age-adjusted incidence rate during the interval from 1981 to 1987, with rates increasing from 4.4 x 10(-6) in 1981 to 7.1 x 10(-6) in 1987. However, when patients with Kaposi sarcoma (KS) (International Classification of Diseases for Oncology [ICD-O] code 9140) were eliminated from this analysis, the rates remained relatively unchanged throughout the time period. Additional stratification by age, gender, and race revealed no important differences in this observed lack of a time trend. Gastrointestinal tract cases were examined separately, and no significant changes in incidence rates were observed. CONCLUSIONS: It appears as though the increase in STS during this time period is accounted for primarily by KS, perhaps because of the acquired immune deficiency syndrome epidemic (since single men between the ages of 20 and 59 years accounted for almost 69% of all cases of KS). Additional studies that examine other populations or time periods after 1987 might be useful.

Adolescent↗
PubMed1993

Patterns of care.

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Adolescent↗
PubMed1993

Pediatric cancer in the United States. A preliminary report of a collaborative study of the Childrens Cancer Group and the Pediatric Oncology Group.

BACKGROUND: Cancer is the second leading cause of death in children younger than 15 years. Although 5-year survival rates have increased dramatically for many childhood tumors, more than 100,000 person-years of life are lost to childhood cancer each year. The exact proportion of pediatric patients with cancer who receive care at centers that use up-to-date therapeutic protocols (such as those affiliated with the Childrens Cancer Group (CCG) or the Pediatric Oncology Group (POG) is unknown. METHODS: Based on residence at the time of diagnosis, observed numbers of pediatric cancer cases seen by member institutions of the CCG and the POG in 1989 and 1990 were compared with the expected number of cases. Expected values were calculated from incidence rates obtained from the Surveillance, Epidemiology and End Results Program and population counts obtained from the US Census Bureau. RESULTS: Results indicate that more than 90% of children younger than 15 years who have a diagnosis of malignant neoplasm are seen at an institution that is a member of either CCG or POG. The highest proportion seen occurs in the youngest (0-4 years) age group, and the proportion declines steadily with increasing age. CONCLUSIONS: There are specific regions within the United States where the observed number of cases was substantially less than the expected number, including areas of Texas, Idaho, and Virginia. Although the exact reasons for these potential deficits are unknown, additional study of these areas is recommended.

Adolescent↗
PubMed1993

Difficulty becoming pregnant and family history as interactive risk factors for postmenopausal breast cancer: the Iowa Women's Health Study.

We recently provided data from a prospective cohort study of postmenopausal women which suggested that a first livebirth at age 30 or older (cf before age 20) was associated with a twofold increased risk of breast cancer in women without a family history, but a 5.8-fold higher risk in women with a positive family history. To address the question of whether these observations reflect difficulty becoming pregnant or maintaining a pregnancy, we performed additional analyses in which the outcome of each pregnancy was considered. During five years of follow-up, 620 incident cases of breast cancer were identified in the 37,105 women at risk. There was little evidence for an increased risk associated with a history of spontaneous abortion (relative risk [RR] = 1.1; 95 percent confidence interval [CI] = 0.9-1.4), nor was the risk higher among women who reported two or more spontaneous abortions in consecutive pregnancies (RR = 1.0, CI = 0.7-1.4). Although women who reported that they had tried unsuccessfully to become pregnant had only slightly and nonsignificantly elevated risks of breast cancer (RR = 1.1, CI = 0.9-1.3), a more pronounced and statistically significant association was noted in women with a positive family history (RR = 2.1, CI = 1.4-3.2). There was a strong inverse association between failure to become pregnant and parity (P < 0.0001); nearly 50 percent of the nulliparous married women reported having tried and failed to become pregnant, whereas the frequency was only 6.8 percent among married women with five or more livebirths.(ABSTRACT TRUNCATED AT 250 WORDS)

Abortion, Spontaneous↗
PubMed1993

Platelet-derived growth factor and risk factors for colorectal cancer.

Platelet-derived growth factor (PDGF) is a potent mitogen for a variety of cells. Abnormal PDGF activity has been reported in many chronic diseases including cancer. Existing data suggest that fluctuations or reset homeostasis in normal growth factor production due to specific agents or changes in cellular environment are potential mechanisms of colonic carcinogenesis. Currently identified risk factors for colorectal cancer include diet, non-steroidal anti-inflammatory drug use, alcohol consumption and physical activity. Certain constituents of diet, including retinoids, fish oils and soybeans, inhibit the activity of PDGF and could reduce paracrine stimulation of the colonic epithelium. Aspirin and physical activity, through reduction in platelet aggregation, may inhibit platelet release of PDGF and lead to reset homeostasis. Alcohol affects platelet aggregation and, depending on consumption patterns, could alter platelet release of PDGF. It is important to determine which of these environmental factors may result in transient effects on growth factor activity and which result in long-term adaptive responses. Further studies could examine the impact of these risk factors on (1) growth factor communication between colonic epithelial cells and fibroblasts in vitro and (2) PDGF concentrations and mitogenic activity in blood and tissue obtained in population-based studies of colorectal cancer.

Alcohol Drinking↗
PubMed1991

The association of blood pressure with cancer incidence in a prospective study.

A cohort of 8,006 Japanese-American men living in Hawaii was examined from 1965 to 1968 and followed for about 20 years. The study identified 1,155 incident cases of histologically confirmed cancer and 648 deaths due to cancer. There was no association between systolic or diastolic blood pressure and total cancer incidence or deaths due to cancer. The relative risk was 1.03 for cancer incidence and 1.00 for cancer mortality for subjects with a systolic pressure of 160 mmHg or greater. Adjustment was made for age, smoking, alcohol, and measures related to obesity. When cancers of specified sites were studied, blood pressure was positively associated with the incidence of kidney cancer (17 cases). After adjustment for the significant effect of taking antihypertensive medication, the effect of blood pressure became nonsignificant. Among seven other cancer sites, there were no statistically significant associations with blood pressure after adjustment for confounding factors.

Antihypertensive Agents↗
PubMed1990

Increasing incidence of primary gastric lymphoma.

Both the incidence and mortality rates of gastric cancer have been consistently declining over the past several decades in the United States. In contrast, the incidence of gastric lymphoma may have been increasing during this time. Based on data from the Surveillance, Epidemiology and End Results (SEER) Program, annual incidence rates of gastric lymphoma from 1973 to 1986 were examined. There was a twofold increase in the age-adjusted incidence rates of gastric lymphoma during this time. This increase occurred in both men and women but was limited to people over 60 years of age. Although the reasons for this increase are unknown, the authors speculate that this may be a true increase since neither differences in SEER coding practices nor changes in diagnostic procedures could explain these observations.

Abdomen↗
PubMed1990

A prospective study of stomach cancer and its relation to diet, cigarettes, and alcohol consumption.

From 1965 to 1968 in Hawaii, 7990 American men of Japanese ancestry were interviewed and examined in a cohort study. The intake of 20 separate foods in a food frequency questionnaire and the intake of carbohydrate and other nutrients, based on a 24-h diet recall history, were recorded. Since then, 150 incident cases of stomach cancer have been identified. Although men with stomach cancer (cases) consumed pickles and ham/bacon/sausages more often and fruits and fried vegetables less often than men without cancer (noncases), none of the differences was statistically significant. Current cigarette smokers had an increased risk (relative risk = 2.7; 95% confidence interval = 1.8 to 4.1) compared with nonsmokers, but there was no dose-response effect with heavier cigarette smoking. The consumption of alcohol, either from beer, spirits, or wine, did not affect the incidence of stomach cancer. The failure to detect an association with dietary foods in this study may be due to the omission of many oriental foods in the questionnaire and the limitations of the 24-h diet recall history.

Age Factors↗
PubMed1990

Cigarette smoking and acute nonlymphocytic leukemia.

In a case-control study of acute nonlymphocytic leukemia in western Washington state, cigarette smokers experienced a twofold increased risk of acute nonlymphocytic leukemia compared with nonsmokers. Risk increased significantly with the number of pack-years smoked (p = 0.0008) and decreased with the number of years stopped smoking (p = 0.15). The increased risk in smokers appeared to be limited to those who inhaled into the chest. The authors suggest that further studies of this potential relation are warranted, especially since the prevalence of cigarette smoking is relatively high in our society.

Case-Control Studies↗
PubMed1989

A prospective study of demographics, diet, and prostate cancer among men of Japanese ancestry in Hawaii.

Prostate cancer incidence was prospectively studied among 7999 men of Japanese ancestry who were first examined between 1965 and 1968 and then followed through 1986. During this surveillance period, 174 incident cases of prostate cancer were recorded. Prostate cancer was not associated with any measure of socioeconomic status, including amount of education, type of occupation, and type of residence. There was also no relationship with the number of children, as a surrogate measure of sexual activity. Increased consumption of rice and tofu were both associated with a decreased risk of prostate cancer, while consumption of seaweeds was associated with an increased risk of prostate cancer. There was no relationship between prostate cancer and the intake of various nutrients, including total fat and total protein. Etiological implications of these associations are discussed, but more research is needed on these dietary factors and the subsequent development of prostate cancer before any firm conclusions can be drawn.

Diet↗
PubMed1989

Acute myelocytic leukemia and prior allergies.

The relationship between prior allergies and adult acute myelocytic leukemia was investigated in a population-based case-control study. Based on data from personal interviews of 98 cases and 133 controls, a history of any type of allergy was associated with a significantly decreased risk of acute myelocytic leukemia (OR = 0.35, 95% CI = 0.20-0.60). Risk declined with the total number of specific allergies reported (p less than 0.001), and was reduced in relation to a history of prior asthma, eczema and hives. The implications of these findings in relation to natural immune surveillance against developing neoplasms are discussed.

Adult↗
PubMed1989

A prospective analysis of physical activity and cancer.

Previous studies have suggested that increased physical activity may be protective against colon cancer. Most of these studies measured activity indirectly. The present study evaluated several direct measurements of physical activity and also resting heart rate as determined from an electrocardiogram. Increased activity was consistently associated with a decreased relative risk of colon cancer for each measure of activity. The colon cancer relative risk estimates for the middle and upper tertiles of a physical activity index (compared with the lower tertile) were 0.56 (95% confidence interval (CI) 0.39-0.80) and 0.71 (95% CI 0.51-0.99), respectively. Relative risk of colon cancer associated with moderate or heavy activity at home/recreation (compared with mostly sitting) was 0.66 (95% CI 0.49-0.88). A similar comparison of activity at work resulted in a relative risk estimate of 0.72 (95% CI 0.52-1.00). Relative risk of colon cancer increased significantly (p = 0.027) with increasing resting heart rate. Relative risks associated with physical activity were also evaluated for cancers of the stomach, rectum, lung, prostate, and urinary bladder. An increased relative risk of stomach cancer was associated with several measures of increased activity, but these results are preliminary and additional research is necessary to further evaluate this finding.

Colonic Neoplasms↗
PubMed1988

Body mass and prostatic cancer: a prospective study.

Previous studies have suggested that increased body mass is associated with an increased risk of prostatic cancer, but these studies have been limited by the fact that they were based on a few simple measurements such as height and weight. Similar results were found in a prospective study of the incidence of prostatic cancer in a cohort of Japanese men born in 1900-19 and living in Hawaii. Further evaluation of the extensive anthropomorphic measurements made in this cohort suggested that the association between measures of body mass and prostatic cancer might be accounted for more by lean tissue than by fat tissue. There was a significant positive association of the risk of prostatic cancer with area of muscle in the arm but not with area of fat in the arm. Further research is needed on the biological mechanisms of carcinogenesis that may be related to both lean and fat tissue and the development of prostatic cancer.

Adipose Tissue↗