Incidence, cancer 804 INDEX

Mortality data are frequently used in cohort studies as opposed to incidence data because of the relative ease of obtaining information on deaths. In particular, the advent of the National Death Index has made mortality data more readily available. While all states maintain registries of incident cancer cases, many of the registries are relatively new and data quality can vary from state to state. Investigators conducting follow-up studies are required to comply with each state s requirements for use of the data. For cancers such as pancreatic cancer where survival is poor, mortality data is an excellent surrogate for the risk of the disease. For other cancers where the survival is much better, such as testicular cancer, mortality is a poor estimator of incidence. Table 15.5 describes the 5-year survival for several selected cancer sites for the period 1996-2004. As evident from the table, there is a considerable difference in survival rates for cancer of different sites. The 5-year survival rate for pancreatic cancer was only 5.1% compared to a survival rate of 98.9% for prostate cancer (SEER 2008). 

In short-term renal toxicity studies in rats gavage administration of 1,1,2,2-tetra-chloroethane caused renal toxicity as evidenced by an increased renal tubule cell labeling index, indicating replicative DNA synthesis. In 2-year studies 1,1,2,2-tetrachloroethane administered by gavage produced an increased incidence of hepatocellular carcinomas in mice but not in rats. In one epidemiological study of exposed army workers there was a slight increase in deaths due to genital cancer and leukemia. Exposure levels were not available,... 

Based on the assumptions described above, the risk calculated using the RESRAD code (Yu etal., 1993) and EPA slope factors (HEAST, 1991 1995) is a probability of cancer incidence of about 7 X 10 4. The assumed acceptable risk for low-hazard waste is 10 3 (see Table 7.1), resulting in a risk index of 0.7. Hence, domestic uranium mill tailings could be classified as low-hazard waste acceptable for licensed near-surface disposal under conditions of perpetual institutional control over disposal sites. 

The exposure scenario described in the previous example of domestic uranium mill tailings was used to classify the high-radium residues. The risk and dose assessments indicated a probability of radiation-induced cancer incidence of about 0.6, potential doses in excess of 10 Sv, and a risk index between 50 and 100. Thus, these residues would be classified as high-hazard waste, even under conditions of perpetual institutional control over near-surface disposal sites, and they would require some form of greater confinement disposal well below the ground surface. This conclusion is consistent with recommendations for disposition of these residues (NAS/ NRC, 1995b). 

Ries, L. A. G., Melbert, D., Krapcho, M., Stinchcomb, D. G., Howlader, N., Homo-, M. J., Mariotto, A., Miller, B. A., Feuer, E. J., Altekruse, S. F., Lewis, D. R., Qegg, L., Eisner, M. R, Reichman, M., and Edwards, B. K. (2008). Annual SEER incidence and US death rats 1975-2005, National Cancer Institute, Bethesda MD, based on November 2007 SEER data submission, posted to the SEER website, 2008. http //seer.cancer.gov/csr/1975 2005/index.html. 

The cohort was assessed by questionnaire for incidence of new cases of prostate cancer from 1989 to 1994. Higher levels of selenium in toenail clippings were significantly associated with a reduced risk of prostate cancer. After controlling for factors such as a family history of prostate cancer, body mass index, calcium intake, lycopene intake, saturated fat intake, vasectomy, and geographical region, the odds ratio (OR) was 0.35 (95% 0=0.16-0.78, P for trend=0.03). 

Renal carcinoma continues to be a major cause of morbidity and mortality worldwide (Table 16.12). Last year, approximately 54,000 new renal tumor patients were diagnosed and 13,000 deaths were ascribed to renal cancer in the United States. Renal cell carcinoma (RCC) is the seventh most common neoplasm in American males and the ninth most common neoplasm in females. There is a twofold to threefold male predominance of RCC incidence but no obvious racial predilection. Recognized risk factors include tobacco smoking, obesity (body mass index >29 may double the risk of RCC) and acquired or hereditary polycystic diseases. The classic clinical presentation symptom triad of flank pain, hematuria, and palpable mass is no longer the... 

The incidence of this comphcation has been analysed using hospital records from a large institution in Wisconsin over 8 years [26 ]. Documentation on 1105 patients with breast cancer pointed to 24 cases of NASH (2.2%). Seven patients had NASH before their diagnosis of breast cancer, but 17 developed NASH after the diagnosis of breast cancer. In multivariate analysis, the factors associated with NASH were use of tamoxifen (OR = 8.2 95% Cl=1.1, 64), body mass index (BMI) (OR=1.1 95% CI=1.1, 1.2), and age (OR=0.95 95% 0=0.91, 0.99 NASH improved after tamoxifen was stopped. After discontinuation of tamoxifen, aminotransferases returned to normal in 14 of 16 patients. NASH was thus associated with the use of tamoxifen but improved when tamoxifen was stopped. 

Table 17.1 depicts nine reports on findings of increased lung cancer incidences and mortdities in both battery and smelter workers with elevated Pb exposures and one report derived from Pb exposure monitoring analysis. These cohorts and other subjects were from Britain, Finland, Italy, Sweden, and the United States. Pb exposures were indexed by actual environmental measurements in air or measurements of Pb in blood and urine. A job-exposure matrix approach was employed in part of one study using a nested case—control approach. 

Risks from other pathways of exposure and/or other chemicals of concern are considered to be additive unless there is evidence that the toxicities of two or more chemicals are synergistic (i.e., enhance each other so that risk is greater than the sum of the risk from either chemical alone) or inhibitory (i.e., interfere with each other so that risk is less than the sum of the risk from either chemical alone). Very little is known about the interactions between toxic chemicals, and risks from multiple chemicals and multiple exposure pathways are usually added together to obtain an estimate of total risk. In the case of noncancer health risk, the hazard index (HI) is calculated separately for each chemical and each exposure pathway, and total risk is equal to the sum of the HI values from aU chanicals and aU pathways. In the case of cancer risk, the cancer incidence is calculated for each ch ical and each exposure pathway, and total risk is equal to the sum of the caucer incideuces from all chemicals and all pathways. Cancer risk is the probability of getting cancer (morbidity), not the probability of dying from cancer (mortality). Many people get cancer and survive. 

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