Incidence and Mortality

Incidence and Mortality

Endometrial cancer is the most common invasive gynecologic cancer in U.S. women, with an estimated 40,100 new cases expected to occur in 2008.[1] This disease primarily affects postmenopausal women at an average age of 60 years at diagnosis.[2] In the United States, it is estimated that approximately 7,470 women will die of endometrial cancer in 2008.[1] The endometrial cancer mortality rate has declined about 25% from 1974 to the present.[3] In the interval from 1973 to 1978, there was a transient increase in the incidence of endometrial cancer without an associated increase in mortality. This phenomenon corresponded with increased use of estrogen replacement therapy at that time. Endometrial cancer rates across the board would be somewhat higher if they were adjusted for the portion of the female population who have undergone hysterectomy. One study estimated that adjustment for age-specific hysterectomy would yield a uterine cancer incidence rate that was approximately 20% higher.[4]

In the mid-1970s, the diagnosis of approximately 15,000 cases of postmenopausal endometrial cancers in excess of those expected on the basis of the underlying secular trend, has been related to the use of exogenous estrogen therapy.[5] In addition to the risk of developing endometrial cancer in association with the use of estrogen replacement therapy unaccompanied by progesterone, a number of additional risk factors have been identified and often appear to be related to estrogenic effects. Among these factors are obesity, a high-fat diet, reproductive factors like nulliparity, early menarche and late menopause, polycystic ovarian syndrome, and tamoxifen use.

Women with hereditary nonpolyposis colorectal cancer (HNPCC) syndrome have a markedly increased risk of endometrial cancer compared with women in the general population. Among women who are HNPCC mutation carriers, the estimated cumulative incidence of endometrial cancer ranges from 20% to 60%.[6,7]

Major differences exist between black and white women in stages of endometrial cancer at detection and subsequent survival. Even though the incidence of endometrial cancer is lower among black women, mortality is higher. The National Cancer Institute initiated a Black/White Cancer Survival Study [8] and found that black women with endometrial cancer had higher-grade and more aggressive histologies than white women.[9] It is difficult to disentangle the effects that biology and socioeconomic status may have on the lower survival rates of African American women with endometrial cancer. Evidence suggests that lower income is associated with advanced-stage disease, lower probability of receiving a hysterectomy, and lower survival rates.[9] Other studies, however, have not found a black/white difference in the interval from patient-reported symptom recognition to initial medical consultation and concluded that it is unlikely that patient delay after the onset of symptoms could explain much of the excess of advanced-stage disease found in black women.[10] Further research is necessary to understand why black women tend to be diagnosed with more aggressive disease and have a higher probability of dying than white women, despite their lower incidence of endometrial cancer.

Factors that have been associated with a decreased incidence of endometrial cancer include parity, lactation, use of combined oral contraceptives, a diet low in fat and high in plant foods, and physical activity. Accumulating information about factors that may contribute to an increase in endometrial cancer risk indicates the target populations where preventive interventions are most needed. In some cases the etiologic evidence has suggested strategies that may be pursued to reduce endometrial cancer risk.

References

1. American Cancer Society.: Cancer Facts and Figures 2008. Atlanta, Ga: American Cancer Society, 2008. Also available online. Last accessed October 1, 2008. 
   
   
2. American Cancer Society.: Detailed Guide: Endometrial Cancer: What are the Risk Factors for Endometrial Cancer? Atlanta, Ga: American Cancer Society, 2005. Available online. Last accessed August 14, 2008. 
   
   
3. Ries LAG, Eisner MP, Kosary CL, et al.: SEER Cancer Statistics Review, 1975-2001. Bethesda, Md: National Cancer Institute, 2004. Also available online. Last accessed August 28, 2008. 
   
   
4. Howe HL: Age-specific hysterectomy and oophorectomy prevalence rates and the risks for cancer of the reproductive system. Am J Public Health 74 (6): 560-3, 1984.  [PUBMED Abstract]
   
   
5. Jick H, Walker AM, Rothman KJ: The epidemic of endometrial cancer: a commentary. Am J Public Health 70 (3): 264-7, 1980.  [PUBMED Abstract]
   
   
6. Watson P, Vasen HF, Mecklin JP, et al.: The risk of endometrial cancer in hereditary nonpolyposis colorectal cancer. Am J Med 96 (6): 516-20, 1994.  [PUBMED Abstract]
   
   
7. Aarnio M, Mecklin JP, Aaltonen LA, et al.: Life-time risk of different cancers in hereditary non-polyposis colorectal cancer (HNPCC) syndrome. Int J Cancer 64 (6): 430-3, 1995.  [PUBMED Abstract]
   
   
8. Barrett RJ 2nd, Harlan LC, Wesley MN, et al.: Endometrial cancer: stage at diagnosis and associated factors in black and white patients. Am J Obstet Gynecol 173 (2): 414-22; discussion 422-3, 1995.  [PUBMED Abstract]
   
   
9. Madison T, Schottenfeld D, James SA, et al.: Endometrial cancer: socioeconomic status and racial/ethnic differences in stage at diagnosis, treatment, and survival. Am J Public Health 94 (12): 2104-11, 2004.  [PUBMED Abstract]
   
   
10. Coates RJ, Click LA, Harlan LC, et al.: Differences between black and white patients with cancer of the uterine corpus in interval from symptom recognition to initial medical consultation (United States). Cancer Causes Control 7 (3): 328-36, 1996.  [PUBMED Abstract]
    
    

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