TABLE 5.5 Selected Epidemiologic Studies—Skin Cancers and Exposure to Insecticides

Reference

Study Population

Exposed Cases

Estimated Relative Risk (95% CI)

Insecticides

Case-Control Study

Gallagher et al., 1996

Residents of Alberta, Canada

 

 

 

Basal cell carcinoma

50

1.3 (0.9–2.1)

 

Squamous cell carcinoma

57

1.7 (1.1–2.7)

 

Low insecticide exposure

21

0.7 (0.3–1.4)

 

High insecticide exposure

36

2.8 (1.4–5.6)

 

p trend=0.02

FEMALE REPRODUCTIVE CANCERS

Female reproductive cancers include cancers of the breast, cervix, uterus, and ovaries. Breast cancer (ICD-9 174.0–174.9 for females) is the most common form of cancer among women and the second most common cause of death from cancer in women, exceeded only by lung cancer (ACS, 2001e). ACS estimates that nearly one in eight women in the United States will have breast cancer. If the tumor is diagnosed while still localized, however, the 5-year survival rate is 96% (ACS, 2002a).

Although considerable efforts have been made, little is known about the etiology of breast cancer. Risk factors generally include family history, mutations in the BRCA1 or BRCA2 (tumor-suppressor) genes, atypical breast hyperplasia, early menarche, late menopause, late childbearing or nulliparity, high breast density, exposure to ionizing radiation, hormone use, obesity, and alcohol use (ACS, 2001e; NCI, 2002m). However, many women who develop breast cancer do not have any of those risk factors.

Most cancers of the cervix (ICD-9 180.0–180.9) are squamous cell carcinomas, and the 5-year survival rate is about 70%. Women are at greater risk for cervical cancer if they or their partners began having sexual intercourse before the age of 18 years or if they have had many sexual partners. That is because of the correlation of cervical cancer and human papilloma viruses, which are believed to initiate abnormal cervical growth (NCI, 2002n).

About one in 57 US women will develop ovarian cancer (ICD-9 183.0) (NCI, 2002o). In contrast with the high 5-year survival rates for other female reproductive cancers, the survival rate for ovarian cancer is 52%. However, if diagnosed early and treated while localized, the 5-year survival rate is 95%. Because of its vague signs and symptoms (such as enlargement of the abdomen and digestive disturbances), ovarian cancer is not always detected early (ACS, 2002a). Risk factors for ovarian cancer include family history, age, childbirth, and the use of fertility drugs, hormone replacement therapy, or talc powder in the genital region (ACS, 2002a).

The 5-year survival rate for cancer of the uterus (ICD-9 179.0–182.8) is a relatively high at 84%. The incidence is higher among white women than among black women, but the case-fatality rate is reversed with black women having nearly twice as high fatality as white women. A major risk factor for uterine cancer is high cumulative exposure to estrogen. Use of estrogen-replacement therapy or tamoxifen, early menarche, late menopause, never having children, and lack of ovulation over long times are risk factors associated with the development of cancer of the corpus, or body, of the uterus. In contrast, pregnancy and the



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