Breast cancer incidence rate

The observation that breast cancer incidence rates vary 10-fold between countries suggests that environmental factors play an important role in the etiology of breast cancer. Perhaps the most compelling evidence is derived from studies of Asian women who migrated from Japan to the San Francisco Bay area. Although the incidence of breast cancer in Asian women is quite low (about 97 cases per 100,000 women), the incidence of breast cancer in Asian women who were bom in the United States, or who migrated from Asia to the United States, gradually increases to equal that of the white population in the same area. 

The Committee also concluded that this comparison of gross carrageenan consumption in the USA with national breast cancer incidence rates cannot prove causation. No adjustment was made for non-food consumption, and consumption was analysed as though it was distributed equally throughout the population. Similarly, no adjustments were made for possible relationships between the 13 gums studied and any of the acknowledged risk factors for mammary carcinoma. 

FIGURE 125-1. Breast cancer incidence and mortality rates by race,... 

Japanese women and women of Japanese origin living in Hawaii but who consume a diet similar to the traditional Japanese diet (rich in soy products) have a low breast cancer incidence and mortality. Women in the Far East who have low rates of breast cancer are thought to consume approximately 30-50 times more soy products than women in the United States. A case-control study in Singapore found that premenopausal women who consumed 55 g of soy per day had a 50% reduced risk of breast cancer compared to women who infrequently consumed soy foods. A high intake of miso soup has been associated with a reduced risk of breast cancer in Japanese women. In prospective trials, a trend toward an inverse association between intake of tofu and subsequent risk of breast cancer and an inverse association between intake of miso soup and development of breast cancer have been found. However, a large prospective study in Japan did not show any effect of soy consumption on breast cancer risk, although this may be because dietary intake was studied in adult women rather than in children or adolescents. A number of studies in rodents have indicated that a protective effect of a soy isoflavone-rich diet may... 

Breast cancer is one of the most common forms of cancer affecting women and, in Western countries, the incidence is rising. The risk of breast cancer increases markedly with age, although a decrease in the rate occurs after the menopause, suggesting that development is hormone-dependent. To date, a number of hormone-related risk factors have been identified (Bingham et al, 1998). Countries such as Japan have relatively low rates of breast cancer, which have been associated with consumption of a diet high in soy foods. Currently, however, the data from epidemiological studies is inconclusive. 

Although the incidence of breast cancer has been increasing in the United States, the mortality rate has been decreasing over the past two decades. This trend reflects the success of early detection and the development of effective treatment regimens. Treatment for most breast cancer patients includes a combination of pharmacologic and nonpharmacologic therapy. 

Breast cancer has a very high incidence in women. Breast cancer frequently develops into (or is) a systemic disease. The best way to reduce risk due to breast cancer is early tumor detection and surgical removal. The increase in detection rate of breast tumors that are < 1 cm in diameter over the past 10 years can be mostly attributed to improvements in the sensitivity and utilization of mammography. The main utility of CA 15-3 in breast cancer is to monitor patients after mastectomy (14). 

The rate of invasive ER-positive breast cancer, a secondary objective in the MORE trial, showed an 84% reduction after 4 years of followup (Cauley et al. 2001) moreover, during the subsequent 4 years of followup in the so-called CORE trial (Continuous Outcomes Relevant to Evista), invasive ER-positive breast cancer, the primary objective of the study, was reduced by 66%. Over the 8 years of both trials, the incidences of invasive breast cancer and ER-positive invasive breast cancer were reduced by 66% and 76%, respectively, in the raloxifene group compared with the placebo group (Martino et al. 2004). These effects have not been associated with harmful effects on the endometrium (Cohen et al. 2000) or the pelvic floor (Goldstein et al. 2001). 

Fig. 10.11. Annual incidence rate per 1000 woman-years of followup for invasive breast cancers over the 8 years of CORE according to ER status. Reproduced with permission from Martino et al. (2004a)...

Cancer is the uncontrolled growth of abnormal cells. It is as old as the existence of animals— cancers are found even in dinosaur bones. Approximately 110 types of cancer have been characterized. In particular, breast cancer (second only to lung cancer in terms of fatality rate) strikes one in eight women and there are approximately 200,000 annual incidents in the United States alone. Twenty-five percent of women with breast carcinoma will even-mally die from their disease. The current arsenal of treatment for breast cancer includes... 

The following data (Table 3.4) are taken from Piccart-Gebhart et al. (2005) who compared trastuzumab after adjuvant chemotherapy in HER2-positive breast cancer with observation only. The binary outcome here is one or more serious adverse events (SAEs) versus no SAEs during the one year trial. The rate in the observation only group provides the background incidence of SAEs. 

In Section 3.2.2 we presented data from a clinical trial comparing trastuzumab to observation only after adjuvant chemotherapy in HER2-positive breast cancer. The incidence rates in the test treatment and control groups were respectively 7.0 per cent and 4.7 per cent. 

Age-adjusted mortality rates for cancer at different sites in U.S. males are shown in Figure 1. It is evident from these data that cancer of the lung has steadily increased in males since 1935 corresponding to an approximate 20-year lag period after cigarette smoking first became popular. In marked contrast to this, the incidence of cancers of the colon and rectum, breast and prostate have increased only at a low rate since 1940. We logically conclude that industrial pollution, food additives, synthetic chemical products, etc., the levels of which have increased dramatically in our environment, are not associated with the development of these three cancer types. On the other hand, the mode of cooking has remained similar over this period, and thus is consonant with the cancer incidence data. 

Interest in dietary components which explain differences in breast cancer rates comes from strong correlations between nutrient supply within nations and their age-adjusted rates for breast cancer (11). The most frequently cited dietary components related to higher risk of breast cancer are total fat, total protein, calories, animal fat, animal protein, and a lack of fiber. Overall it has not been possible to identify the specific dietary constituents responsible for the observed incidence since the intakes of many dietary factors such as protein, fat, and calories are strongly intercorrelated. Other studies of nutrient intake and breast... 

Further demonstration of the utility of raloxifene in the prevention of breast cancer came from the STAR trial (Study of Tamoxifen and Raloxifene), which followed more than 19,000 post-menopausal women for 5 years. This was a prospective, doubleblind, randomized trial comparing 20 mg/day tamoxifen versus 60 mg/day raloxifene, which resulted in the demonstration that incidence rates of invasive breast cancer for both treatments were comparable.39... 

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