National Cancer Institute monograph最新文献

Five approaches for the evaluation of occupational factors in cancer etiology are described. These approaches, based on one's having access to cancer registry data, are for examining cancer profiles for industry and occupation, evaluating information on occupation and industry to infer exposure, observing time trends in incidence to evaluate tumors of occupational interest, using cases of interest to form the basis for case-control studies, and linking cohorts with known exposure to the tumor registry to ascertain cancer incidence in that cohort.

A correlation study linking age-adjusted lung cancer mortality rates with indices of air pollution was conducted as a first step in the investigation of the high rate of lung cancer in Liaoning Province. Mortality rates for this cancer during 1976-78 for males and females were elevated in the large industrial cities with metallurgical processing and machinery manufacturing industries, after smoking was taken into account. However, there was little correlation between measures of total suspended particulates and lung cancer rates across the 10 major cities of the Province. Neighborhood air pollution indices correlated significantly with local commune mortality rates within the largest city, and lung cancer rates were higher near certain point sources of industrial pollution (including a copper-zinc smelter). These findings indicate that the atmospheric pollution in this northern Chinese province may contribute to lung cancer risk and that further analytic epidemiologic study in this high-risk area is warranted for evaluation of the role of outdoor and indoor air pollutants.

Among 4,184 patients with cancer of the esophagus, 55 second primary cancers were observed, whereas 64 were expected [relative risk (RR) = 0.86]. The absence of an excess risk of alcohol- and tobacco-related cancers was not anticipated. A significant 19% deficit of second cancers was found among 30,843 patients with stomach cancer. Cancer of the rectum, kidney, and lung all occurred significantly below expectation. An excess risk of ovarian cancer (RR = 1.9) was seen in women. Reasons for these findings are not entirely clear. Cancer of the small intestine is rare, and despite a relatively short survival expectation, a moderate excess of second cancers was seen among 868 patients (36 vs. 26.8). Only cancers of the liver and gallbladder were significantly elevated, and the possibility of misclassified metastases is discussed. Colon cancer is one of the most common cancers in Denmark, and 29,490 patients with this disease were at slightly lower risk for development of second cancer (RR = 0.96; 95% confidence interval = 0.9-1.0) than the general Danish population, excluding secondary colon cancers. Esophageal, stomach, and liver cancers occurred less frequently than expected. That cancers of the uterine corpus and ovary were significantly increased supports the notion that common risk factors, such as diet and endogenous hormones, influence the development of these cancers. A significant 23% deficit of second cancers was also found among 26,597 patients with cancer of the rectum, excluding secondary rectal cancer. Significant deficits were seen for cancers of the stomach (RR = 0.5), lung (RR = 0.8), and brain (RR = 0.5), and for multiple myeloma (RR = 0.4). The likelihood of underreporting of second cancers, especially of the digestive system, is discussed. However, cancer of sites previously reported to be associated with rectal cancer, e.g., the colon, breast, and uterus, did not occur below expectation. Cancers of the liver and biliary tract occurred in 4,453 patients; their average survival was only 1 year. Except for a slight excess of cancer of the ovary (5 vs. 1.6), the risk of second cancer development for all sites was consistent with unity (RR = 0.90). The risk of second cancers among 7,752 persons with cancer of the pancreas was not greater than expected (88 vs. 85.2). Males were at significant risk of kidney cancer (RR = 3.2), whereas females showed elevated rates of cancers of the uterine corpus (RR = 3.2) and ovary (RR = 3.1). No site occurred significantly below expectation.

Patients diagnosed in Connecticut from 1935 to 1982 with cancers of the tongue, gum, floor, and other parts of the mouth, or pharynx experienced twofold to threefold increased risks of developing a second primary cancer. The excesses were most prominent [relative risk (RR) greater than or equal to 10] for subsequent oral and esophageal cancers but also were observed for cancers at other sites in the digestive and respiratory tracts. The increased risks, which affected both men and women and persisted over time, are most likely related to increased alcohol and tobacco consumption in the patients developing second primaries. The proportion of persons developing a new primary was 9% among the 2,120 patients with cancer of the tongue, 14% for the 3,063 patients with cancer in the gum, floor, or other parts of the mouth, and 8% among the 2,637 persons with pharynx cancer. If one considers that the average length of follow-up was only 3.4 years, these percentages are high and indicate the need for continued surveillance of patients with oral and pharyngeal cancers. Small overall excesses of subsequent cancer occurred among patients with initial lip (RR = 1.3) or salivary gland cancers (RR = 1.2), with twofold risks of oral and respiratory cancers evident for both tumors.

Between 1943 and 1980, approximately 53,000 women in Denmark survived 2 or more months after initial diagnosis of cancers of the cervix uteri, corpus uteri, ovaries, fallopian tubes, and ligaments. No significant excess of new cancers was observed following cancers of the cervix and corpus uteri. However, after second cancers of both the cervix and corpus uteri were eliminated from the analysis (because it was likely they were surgically removed or not recorded due to conservative coding practices), 6 and 4% excess risks of borderline significance were found among women with cancer of the cervix and uterus, respectively. A significant 25% excess of all second primary cancers was observed following cancer of the ovary (relative risk = 1.25; 95% CI = 1.14-1.37). Significant excesses of colon and breast cancers followed cancers of the ovary and corpus uteri. Subsequent to cervical cancer, the risk of cancers of the lung, esophagus, bladder, and kidney occurred significantly above expectation. These associations may be explained by common risk factors related to reproduction and possibly diet for cancers of the breast, colon, ovary, and corpus uteri; and to cigarette smoking for cancers of the lung, esophagus, bladder, and cervix uteri. The significant deficit of breast cancer after cervical cancer could be due to different patterns of risk factor (i.e., reproductive and socioeconomic variables) and loss of functioning ovaries as a part of the treatment for cervical cancer. Each of the female genital sites showed significant excesses of second bladder cancers, and the risk increased significantly with time, which indicate a relation to radiotherapy. The pattern of risk of leukemia observed following cancer of the ovary was also compatible with effects of treatment, especially chemotherapy.

The risk of a person developing a second primary cancer was evaluated in approximately 30,000 persons who developed cancer of the respiratory system in Connecticut between 1935 and 1982. A significant 44% excess of all second cancers was observed following cancer of the lung (614 observed vs. 426 expected). The excess of second tumors was 72% following cancer of the larynx (541 vs. 314) and 34% following cancer of the nasal cavities and sinuses (43 vs. 32). For cancers of the lung and larynx, second cancers arose mainly along the respiratory tract or other sites associated with cigarette smoking (oral cavity, bladder, kidney). A threefold excess of esophageal cancer followed cancer of the larynx, which was indicative of risk factors in common (alcohol and tobacco) and possibly an effect of radiotherapy. Radiotherapy may have contributed also to the increased risk of second lung and breast cancers. A slight excess risk of leukemia after lung cancer points to a possible effect of chemotherapy given for certain histologic types. An unexpected finding was a significant 50% increased risk of colon cancer following cancer of the larynx. Significant excesses of prostate cancer are probably artifacts associated with increased medical surveillance and higher autopsy rates among cancer patients than in the general population. No deficits of any second cancers were observed. The risk of a second cancer developing did not appear to vary by sex or time since initial diagnosis, except that the risks following cancer of the nasal cavities and sinuses returned to normal levels among long-term survivors. Among persons observed for 10 or more years after their initial diagnosis of cancers of the lung or larynx, the risk of developing a second cancer remained high, i.e., on the order of 50% above expectation. Further analytic studies should clarify the role of smoking, alcohol, other life-style and host factors, and various forms of therapy on the risk of second cancers following cancer of the respiratory system.

We used epidemiologic data on 2 tumor sites, the intracranial meninges and the parotid gland, to evaluate the importance of medical and dental x rays as risk factors for radiogenic tumors of the head diagnosed among residents of Los Angeles County in recent years. Exposures to x-ray treatment to the head and to full-mouth dental x-ray series before 1960 appear to be risk factors for both meningiomas and parotid tumors. Evidence from both descriptive and analytic studies suggests that the female over male excess of meningiomas, which is greatest from ages 25 to 54 years, may be partially explained by the excess exposure of young women to dental x rays. Study participants' ability to recall diagnostic x rays accurately is also evaluated by our comparisons of interview data to those available from dental charts. Recall of these events appears to be unbiased and accurate enough to justify the use of interview data in investigations of these risk factors.