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John D Boice

Publications and source records attributed to John D Boice.

49 records · Page 3Linked to original sources
PubMed2003

Site-specific cancer incidence and mortality after cerebral angiography with radioactive thorotrast.

Few opportunities exist to evaluate the carcinogenic effects of long-term internal exposure to alpha-particle-emitting radionuclides. Patients injected with Thorotrast (thorium-232) during radiographic procedures, beginning in the 1930s, provide one such valuable opportunity. We evaluated site-specific cancer incidence and mortality among an international cohort of 3,042 patients injected during cerebral angiography with either Thorotrast (n = 1,650) or a nonradioactive agent (n = 1,392) and who survived 2 or more years. Standardized incidence ratios (SIR) for Thorotrast and comparison patients (Denmark and Sweden) were estimated and relative risks (RR), adjusted for population, age and sex, were generated with multivariate statistical modeling. For U.S. patients, comparable procedures were used to estimate standardized mortality ratios (SMR) and RR, representing the first evaluation of long-term, site-specific cancer mortality in this group. Compared with nonexposed patients, significantly increased risks in Thorotrast patients were observed for all incident cancers combined (RR = 3.4, 95% CI 2.9-4.1, n = 480, Denmark and Sweden) and for cancer mortality (RR = 4.0, 95% CI 2.5-6.7, n = 114, U.S.). Approximately 335 incident cancers were above expectation, with large excesses seen for cancers of the liver, bile ducts and gallbladder (55% or 185 excess cancers) and leukemias other than CLL (8% or 26 excess cancers). The RR of all incident cancers increased with time since angiography (P < 0.001) and was threefold at 40 or more years; significant excesses (SIR = 4.0) persisted for 50 years. Increasing cumulative dose of radiation was associated with an increasing risk of all incident cancers taken together and with cancers of the liver, gallbladder, and peritoneum and other digestive sites; similar findings were observed for U.S. cancer mortality. A marginally significant dose response was observed for the incidence of pancreas cancer (P = 0.05) but not for lung cancer. Our study confirms the relationship between Thorotrast and increased cancer incidence at sites of Thorotrast deposition and suggests a possible association with pancreas cancer. After injection with >20 ml Thorotrast, the cumulative excess risk of cancer incidence remained elevated for up to 50 years and approached 97%. Caution is needed in interpreting the excess risks observed for site-specific cancers, however, because of the potential bias associated with the selection of cohort participants, noncomparability with respect to the internal or external comparison groups, and confounding by indication. Nonetheless, the substantial risks associated with liver cancer and leukemia indicate that unique and prolonged exposure to alpha-particle-emitting Thorotrast increased carcinogenic risks.

Adult↗
PubMed2002

Breast cancer mortality among female radiologic technologists in the United States.

We evaluated breast cancer mortality through 1997 among 69 525 female radiologic technologists who were certified in the United States from 1926 through 1982 and who responded to our questionnaire. Risk of breast cancer mortality was examined according to work history and practices and was adjusted for known risk factors. Breast cancer mortality risk was highest among women who were first employed as radiologic technologists prior to 1940 (relative risk [RR] = 2.92, 95% confidence interval [CI] = 1.22 to 7.00) compared with risk of those first employed in 1960 or later and declined with more recent calendar year of first employment (P for trend =.002). Breast cancer mortality risk increased with increasing number of years of employment as a technologist prior to 1950 (P for trend =.018). However, risk was not associated with the total number of years a woman worked as a technologist. Technologists who first performed fluoroscopy (RR = 1.69, 95% CI = 1.02 to 3.11) and multifilm procedures (RR = 1.87, 95% CI = 1.04 to 3.34) before 1950 had statistically significantly elevated risks compared with technologists who first performed these procedures in 1960 or later. The high risks of breast cancer mortality for women exposed to occupational radiation prior to 1950 and the subsequent decline in risk are consistent with the dramatic reduction in recommended radiation exposure limits over time.

Allied Health Personnel↗
PubMed2002

[Cancer in siblings of children with cancer].

INTRODUCTION: In some rare inherited disorders, such as Li-Fraumeni syndrome, relatives of children with cancer are at increased risk of cancer. We aimed to assess relations between childhood cancer and sibling risk, and evaluate the influence of recessive conditions in cancer causation. MATERIAL AND METHODS: We did a population-based cohort study in the Nordic countries of 42,277 siblings of 25,605 children with cancer. Children with cancer were identified from records in the five Nordic cancer registries, and their siblings from nationwide population registries. Cancers in siblings were documented through record linkage with cancer registries and compared with national incidence rates. We also assessed cancer incidence in parents to identify familial cancer syndromes. RESULTS: 284.2 cancers were expected in siblings, whereas 353 were diagnosed (standardised incidence ratio 1.24 95% CI, 1.12-1.38). Risk ratios for siblings were highest in the first decade of life (2.59; 1.89-3.46). We excluded 56 families with genetic syndromes linked to cancer, which reduced this ratio from 1.7 to 1.0 (0.7-1.3) for siblings younger than 20 years and from 1.3 to 1.0 (0.8-1.3) for those aged 20-29 years. We found no new patterns of familial cancer that indicated inherited susceptibility, or evidence that recessive conditions might contribute to cancers not explained by syndromes. 40% of cancers in siblings that occurred before age 20 years could be attributed to known genetic factors, whereas 60% remained unexplained. DISCUSSION: Apart from rare cancer syndromes, paediatric cancer is not an indicator of increased risk in siblings.

Adolescent↗
PubMed2002

Cancer in Korean war navy technicians: mortality survey after 40 years.

This study reports on over 40 years of mortality follow-up of 40,581 Navy veterans of the Korean War with potential exposure to high-intensity radar. The cohort death rates were compared with mortality rates for White US men using standardized mortality ratios, and the death rates for men in occupations considered a priori to have high radar exposure were compared with the rates for men in low-exposure occupations using Poisson regression. Deaths from all diseases and all cancers were significantly below expectation overall and for the 20,021 sailors with high radar exposure potential. There was no evidence of increased brain cancer in the entire cohort (standardized mortality ratio (SMR) = 0.9, 95% confidence interval (CI): 0.7, 1.1) or in high-exposure occupations (SMR = 0.7, 95% CI: 0.5, 1.0). Testicular cancer deaths also occurred less frequently than expected in the entire cohort and high-exposure occupations. Death rates for several smoking-related diseases were significantly lower in the high-exposure occupations. Nonlymphocytic leukemia was significantly elevated among men in high-exposure occupations but in only one of the three high-exposure occupations, namely, electronics technicians in aviation squadrons (SMR = 2.2, 95% CI: 1.3, 3.7). Radar exposure had little effect on mortality in this cohort of US Navy veterans.

Adult↗
PubMed2002

[Use of cellular telephones and risk of cancer. A Danish cohort study].

INTRODUCTION: The use of cellular telephones has been suggested to increase the risk of cancer. MATERIAL AND METHODS: We carried out a retrospective cohort study of the incidence of cancer in all 420,095 users of cellular telephones during the period of 1982 to 1995. RESULTS: Overall, 3391 cancers were found, with 3825 expected, which yielded a significantly decreased standardised incidence ratio of 0.89. No increased incidence was seen for cancers of the brain or nervous system, of the salivary gland or for leukaemia, cancers which were of a priori interest. DISCUSSION: The results do not support the hypothesis of an association between the use of these telephones and tumours of the brain or salivary gland, leukaemia, or other cancers.

Adult↗
PubMed2002

Residential radon and lung cancer risk in a high-exposure area of Gansu Province, China.

In the general population, evaluation of lung cancer risk from radon in houses is hampered by low levels of exposure and by dosimetric uncertainties due to residential mobility. To address these limitations, the authors conducted a case-control study in a predominantly rural area of China with low mobility and high radon levels. Included were all lung cancer cases diagnosed between January 1994 and April 1998, aged 30-75 years, and residing in two prefectures. Randomly selected, population-based controls were matched on age, sex, and prefecture. Radon detectors were placed in all houses occupied for 2 or more years during the 5-30 years prior to enrollment. Measurements covered 77% of the possible exposure time. Mean radon concentrations were 230.4 Bq/m(3) for cases (n = 768) and 222.2 Bq/m(3) for controls (n = 1,659). Lung cancer risk increased with increasing radon level (p < 0.001). When a linear model was used, the excess odds ratios at 100 Bq/m(3) were 0.19 (95% confidence interval: 0.05, 0.47) for all subjects and 0.31 (95% confidence interval: 0.10, 0.81) for subjects for whom coverage of the exposure interval was 100%. Adjusting for exposure uncertainties increased estimates by 50%. Results support increased lung cancer risks with indoor radon exposures that may equal or exceed extrapolations based on miner data.

Adult↗
PubMed2002

Lung cancer following chemotherapy and radiotherapy for Hodgkin's disease.

BACKGROUND: Lung cancer is a frequent cause of death in patients cured of Hodgkin's disease, but the contributions of chemotherapy, radiotherapy, and smoking are not well described. We quantified the risk of treatment-associated lung cancer, taking into account tobacco use. METHODS: Within a population-based cohort of 19 046 Hodgkin's disease patients (diagnosed from 1965 through 1994), a case-control study of lung cancer was conducted. The cumulative amount of cytotoxic drugs, the radiation dose to the specific location in the lung where cancer developed, and tobacco use were compared for 222 patients who developed lung cancer and for 444 matched control patients. All statistical tests were two-sided. RESULTS: Treatment with alkylating agents without radiotherapy was associated with increased lung cancer risk (relative risk [RR] = 4.2; 95% confidence interval [CI] = 2.1 to 8.8), as was radiation dose of 5 Gy or more without alkylating agents (RR = 5.9; 95% CI = 2.7 to 13.5). Risk increased with both increasing number of cycles of alkylating agents and increasing radiation dose (P for trend <.001). Among patients treated with mechlorethamine, vincristine, procarbazine, and prednisone (MOPP), risk increased with cumulative amounts of mechlorethamine and procarbazine (P<.001) when evaluated separately. Statistically significantly elevated risks of lung cancer were apparent within 1-4 years after treatment with alkylating agents, whereas excess risk after radiotherapy began 5 years after treatment and persisted for more than 20 years. Risk after treatment with alkylating agents and radiotherapy together was as expected if individual excess risks were summed. Tobacco use increased lung cancer risk more than 20-fold; risks from smoking appeared to multiply risks from treatment. CONCLUSIONS: Past treatments with alkylating agents and radiation therapy for Hodgkin's disease were associated with an increased risk of lung cancer in a dose-dependent and additive fashion. The precise risk estimates, however, should be interpreted cautiously, given the possible residual and enhancing effects of tobacco.

Adolescent↗
PubMed2002

Study design and cohort characteristics of the Childhood Cancer Survivor Study: a multi-institutional collaborative project.

BACKGROUND: Increased attention has been directed toward the long-term health outcomes of survivors of childhood cancer. To facilitate such research, a multi-institutional consortium established the Childhood Cancer Survivor Study (CCSS), a large, diverse, and well-characterized cohort of 5-year survivors of childhood and adolescent cancer. PROCEDURE: Eligibility for the CCSS cohort included a selected group of cancer diagnoses prior to age 21 years between 1970-1986 and survival for at least 5 years. RESULTS: A total of 20,276 eligible subjects were identified from the 25 contributing institutions, of whom 15% are considered lost to follow-up. Currently, 14,054 subjects (69.3% of the eligible cohort) have participated by completing a 24-page baseline questionnaire. The distribution of first diagnoses includes leukemia (33%), lymphoma (21%), neuroblastoma (7%), CNS tumor (13%), bone tumor (8%), kidney tumor (9%), and soft-tissue sarcoma (9%). Abstraction of medical records for chemotherapy, radiation therapy, and surgical procedures has been successfully completed for 98% of study participants. Overall, 78% received radiotherapy and 73% chemotherapy. CONCLUSION: The CCSS represents the largest and most extensively characterized cohort of childhood and adolescent cancer survivors in North America. It serves as a resource for addressing important issues such as risk of second malignancies, endocrine and reproductive outcome, cardiopulmonary complications, and psychosocial implications, among this unique and ever-growing population.

Adolescent↗
PubMed2002

Trends in reproductive, smoking, and other chronic disease risk factors by birth cohort and race in a large occupational study population.

PURPOSE: To illustrate the value of cohort studies to assess trends in chronic disease risk factors. METHODS: In collaboration with the American Registry of Radiologic Technologists and the University of Minnesota, the National Cancer Institute initiated a cohort study of cancer among radiologic technologists. More than 90,000 technologists who responded to a mailed questionnaire were grouped into ten birth cohorts from before 1920 through 1960 and later, and stratified by self-reported racial/ethnic groups. Trends in height, smoking, and reproductive factors were analyzed. RESULTS: Among the trends observed were that the proportion of young men (< 18 years) smoking generally fell in each birth cohort after 1925, whereas the proportion of young women smoking rose for those born after 1950. Among women born since 1940, the mean age at menarche for white women has remained at 12.5 years, but has declined among black and Asian/Pacific Islander women. Recent birth cohorts (since 1955) show among the highest mean ages at birth of first child (> 26 years), highest rates of nulliparity at age 25 (>/= 63 %), and lowest mean parity levels (< or = 1.7) compared with earlier cohorts. CONCLUSION: Analyses of large cohorts can clarify birth cohort trends in chronic disease risk factors.

Adult↗
PubMed2002

Feasibility of assessing the carcinogenicity of neutrons among neutron therapy patients.

Nuclear workers, oil well loggers, astronauts, air flight crews, and frequent fliers can be exposed to low doses of neutrons, but the long-term human health consequences of neutron exposure are unknown. While few of these exposed populations are suitable for studying the effects of neutron exposure, patients treated with neutron-beam therapy might be a source of information. To assess the feasibility of conducting a multi-center international study of the late effects of neutron therapy, we surveyed 23 cancer centers that had used neutron beam therapy. For the 17 responding institutions, only 25% of the patients treated with neutrons (2,855 of 11,191) were alive more than 2 years after treatment. In a two-center U.S. pilot study of 484 neutron-treated cancer patients, we assessed the feasibility of obtaining radiotherapy records, cancer incidence and other follow-up data, and of estimating patient organ doses. Patients were treated with 42 MeV neutrons between 1972 and 1989. Applying a clinical equivalence factor of 3.2 for neutrons, total average organ doses outside the treatment beam ranged from 0.14 to 0.29 Gy for thyroid, 0.40 to 2.50 Gy for breast, 0.63 to 2.35 Gy for kidney, and 1.12 to 1.76 Gy for active bone marrow depending upon the primary cancer treatment site. We successfully traced 97% of the patients, but we found that patient survival was poor and that chemotherapy was not confirmable in a quarter of the patients. Based on our findings from the international survey and the feasibility study, we conclude that a large investigation could detect a fivefold or higher leukemia risk, but would be inadequate to evaluate the risk of solid cancers with long latent periods and therefore would likely not be informative with respect to neutron-related cancer risk in humans.

Carcinogenicity Tests↗
PubMed2002

Radiation effects on breast cancer risk: a pooled analysis of eight cohorts.

Breast cancer incidence rates after radiation exposure in eight large cohorts are described and compared. The nature of the exposures varies appreciably, ranging from a single or a small number of high-dose-rate exposures (Japanese atomic bomb survivors, U.S. acute post-partum mastitis patients, Swedish benign breast disease patients, and U.S. infants with thymic enlargement) to highly fractionated high-dose-rate exposures (two U.S. tuberculosis cohorts) and protracted low-dose-rate exposure (two Swedish skin hemangioma cohorts). There were 1,502 breast cancers among 77,527 women (about 35,000 of whom were exposed) with 1.8 million woman-years of follow-up. The excess risk depends linearly on dose with a downturn at high doses. No simple unified summary model adequately describes the excess risks in all groups. Excess risks for the thymus, tuberculosis, and atomic bomb survivor cohorts have similar temporal patterns, depending on attained age for relative risk models and on both attained age and age at exposure for excess rate models. Excess rates were similar in these cohorts, whereas, related in part to the low breast cancer background rates for Japanese women, the excess relative risk per unit dose in the bomb survivors was four times that in the tuberculosis or thymus cohorts. Excess rates were higher for the mastitis and benign breast disease cohorts. The hemangioma cohorts showed lower excess risks suggesting ameliorating dose-rate effects for protracted low-dose-rate exposures. For comparable ages at exposure (approximately 0.5 years), the excess risk in the hemangioma cohorts was about one-seventh that in the thymus cohort, whose members received acute high-dose-rate exposures. The results support the linearity of the radiation dose response for breast cancer, highlight the importance of age and age at exposure on the risks, and suggest a similarity in risks for acute and fractionated high-dose-rate exposures with much smaller effects from low-dose-rate protracted exposures. There is also a suggestion that women with some benign breast conditions may be at elevated risk of radiation-associated breast cancer.

Adolescent↗
PubMed2002

Incidence of breast and other cancers among Finnish women with cosmetic breast implants, 1970-1999.

Epidemiologic evidence does not point to a carcinogenic effect of silicone implants on the breast, and evidence for or against a carcinogenic effect at sites other than the breast is limited. To examine subsequent cancer risk among women with cosmetic breast implants, we conducted a cohort study of 2171 women in Finland identified from operation diaries of major hospitals and private clinics, 1970-1999. The nationwide population and health outcome registries in Finland were used to trace these women for cancer incidence through 1999. Standard statistical techniques were used to compute expected values based on general population rates. The measure of risk was taken as the ratio of observed to expected cancers, that is, the standardized incidence ratio (SIR) and its 95% confidence interval (CI). Among the 2171 women with cosmetic breast implants, 30 developed cancer against 33.7 expected (SIR = 0.9,95% CI = 0.6-1.3). There was no evidence for an increase in breast cancer risk (SIR 0.5, 95% CI, 0.2-1.0), even among those followed for more than 10 years (2 observed, 4.6 expected). Stage at breast cancer diagnosis did not differ from that expected nor did incidence of any other cancer. Although hindered by small numbers, the consistency of our results with those of other Nordic studies leads us to conclude that cosmetic breast implants are not a cause of cancer and that they do not appear to delay the detection of breast cancers.

Adult↗