Expanding horizons in breast and prostate cancer prevention and early detection. The 1992 Samuel C. Harvey Lecture

Characteristics of women with breast cancer seen at reference services in the North of Minas Gerais

OBJECTIVE

To describe the main characteristics, including stage of disease and local treatment of patients admitted to two reference services for the treatment of breast cancer in the North of Minas Gerais.

METHODS

We conducted a cross-sectional descriptive study. We evaluated medical records of 288 female patients with breast cancer admitted between January 2006 and December 2009, referred from a public hospital and a private clinic. Variables were analyzed using the chi-square test and multinomial logistic regression.

RESULTS

68.1% of patients were referred from the public hospital. There was a predominance of patients over 50 years old (54.5%), married (59%) and with children (87.8%). The mean age of the population studied was 63 years old. Time between suspected cancer and confirmation of diagnosis was over six months in 42.7% of patients. Cancer diagnosis was late (stage III and IV) in 47.6% of patients. Family history of breast cancer was present in 20.1%, 20.8% of them had performed self-breast examination, and 41% had been submitted to a mammogram.

CONCLUSION

There was a higher prevalence of stage III/IV patients from the public service when compared to the private sector. We found that the major factors associated with the late diagnosis of breast cancer were the delay between suspected and confirmed diagnosis, the absence of family history of breast cancer and not having a mammogram.

A favorable view: progress in cancer prevention and screening

Clifton Leaf, in his article "Why We're Losing the War on Cancer," presents criticisms of past research approaches and the small impact of this research thus far on producing cures or substantially extending the life of many cancer patients. It is true that gains in long-term survival for people with advanced cancers have been modest, hindered in part by the heterogeneity of tumors, which allows the cancers to persist using alternate molecular pathways and so evade many cancer therapeutics. In contrast, clinical trials have demonstrated that it is possible to reduce the incidence or improve cancer survival through prevention and early detection. Strides have been made in preventing or detecting early the four deadliest cancers in the United States (i.e., lung, breast, prostate, and colorectal). For example, 7-year follow-up data from the Breast Cancer Prevention Trial (BCPT) provides evidence that tamoxifen reduces the occurrence of invasive breast tumors by more than 40%; recent studies using aromatase inhibitors and raloxifene are also promising. The Prostate Cancer Prevention Trial (PCPT) showed that finasteride reduced prostate cancer incidence by 25%, and the ongoing Selenium and Vitamin E Cancer Prevention Trial (SELECT) is investigating selenium and vitamin E for prostate cancer prevention based on encouraging results from earlier studies. Living a healthy lifestyle, including regular physical activity, avoiding obesity, and eating primarily a plant-based diet has been associated with a lower risk of colorectal cancer. In addition, noninvasive stool DNA tests for early detection are being studied, which may lessen the reluctance of people to be screened for colorectal polyps and cancer. Behavioral and medical approaches for smoking prevention are ways to reduce the incidence of lung cancer, with antinicotine vaccines on the horizon that may help former smokers to avoid relapse. The US National Lung Screening Trial is testing whether early detection via spiral CT screening will reduce lung cancer mortality. Prevention and earlier detection offer efficient and practical strategies to reduce the cancer burden. Several of the suggestions Mr. Leaf makes, such as developing interdisciplinary collaborations and allocating resources to research earlier in the process of carcinogenesis, have become an integral strategy in the National Cancer Institute's (NCI) approach in the past decade, specifically in the realm of cancer prevention and early detection. For example, an aggressive program to identify biomarkers for earlier detection of cancer--the NCI's Early Detection Research Detection (EDRN)--has identified three promising biomarkers since its establishment in 2000. It collaborates with the National Institute of Standards and Technology and extramural scientists to develop validation standards and to identify the best technologies to use for systematic investigations. If these biomarkers can be validated, they might help to reduce cancer mortality.

The impact of obesity in urology

The incidence and progression of urologic diseases, as well as several urologic cancers.depend on many interrelated factors, such as obesity, diet, genetics, environment, age, and the immune system. Obesity is a risk factor for stress urinary incontinence, ED, infertility, and renal calculi. Numerous publications have demonstrated that a high dietary intake of fat increases prostate cancer risk, although the mechanisms are not clear. Although some reports may demonstrate an association between obesity and prostate cancer, it may be hard to establish because, in general, men with obesity have a high-fat diet. Obesity, recurrent urinary tract infections, increased intake of protein and fried foods, and female sex seem to increase the risk of renal cancer. Environmental toxins seem to be the major factors affecting the incidence of bladder cancers. Thus, dietary modification and other public health measures directed at reducing weight may reduce the incidence of urologic illnesses. More studies are necessary to determine the therapeutic effects of weight loss and dietary modification on the incidence and progression of urologic tumors.

Effects of tissue transglutaminase on retinoic acid-induced cellular differentiation and protection against apoptosis

Retinoic acid (RA) and its various synthetic analogs affect mammalian cell growth, differentiation, and apoptosis. Whereas treatment of the human leukemia cell line HL60 with RA results in cellular differentiation, addition of the synthetic retinoid, N-(4-hydroxyphenyl) retinamide (HPR), induces HL60 cells to undergo apoptosis. Moreover, pretreatment of HL60 cells as well as other cell lines (i.e. NIH3T3 cells) with RA blocks HPR-induced cell death. In attempting to discover the underlying biochemical activities that might account for these cellular effects, we found that monodansylcadaverine (MDC), which binds to the enzyme (transamidase) active site of tissue transglutaminase (TGase), eliminated RA protection against cell death and in fact caused RA to become an apoptotic factor, suggesting that the ability of RA to protect against apoptosis is linked to the expression of active TGase. Furthermore, it was determined that expression of exogenous TGase in cells exhibited enhanced GTP binding and transamidation activities and mimicked the survival advantage imparted by RA. We tested whether the ability of this dual function enzyme to limit HPR-mediated apoptosis was a result of the ability of TGase to bind GTP and/or catalyze transamidation and found that GTP binding was sufficient for the protective effect. Moreover, excessive transamidation activity did not appear to be detrimental to cell viability. These findings, taken together with observations that the TGase is frequently up-regulated by environmental stresses, suggest that TGase may function to ensure cell survival under conditions of differentiation and cell stress.

A medical hypothesis: phosphorus balance and prostate cancer

Over the last three decades the mortality rate for prostatic carcinoma has steadily increased. Carcinoma of prostate (CaP), the most common malignancy in men, is also the second most common cause of cancer deaths in men. However, few epidemiologic studies have been done, and there are scant clues to the etiology/pathogenesis of CaP. As treatment failures for advanced carcinoma continue to frustrate clinicians, more emphasis has recently been focused on strategies to prevent invasive CaP. Prostatic hyperplasia is a universal phenomenon in aging men. Mechanism and signals causing this growth are not understood. Thus, prostatic diseases affect men over the age of 45 and increase in frequency with age so that by the eighth decade more than 90% of men have benign prostatic hyperplasia, of which some progress to CaP. Data from several studies support that higher levels of active metabolite of vitamin D, 1,25-(OH)2-D, reduce the risk of prostatic hyperplasia and CaP. Men with high serum levels of 1,25-(OH)2-D have a reduced risk of poorly differentiated and clinically advanced CaP. Receptor for vitamin D has been reported in both normal and cancer prostate cells. 1,25-(OH)2-D inhibits proliferation and induces differentiation of normal and neoplastic cells. Hypercalcemic activity of 1,25-(OH)2-D or its analogues, however, thwart their use for therapy in humans. 1,25-(OH)2-D also has an established role in phosphorus homeostasis. Low dietary intake of phosphorus leads to an increase in serum concentration of 1,25-(OH)2-D. In addition, dietary fructose reduces plasma phosphate levels by 30 to 50% for more than 3 hr due to a rapid shift of phosphate from extracellular to intracellular compartment. Fruit intake has been shown to be associated with reduced risk of CaP, particularly the advanced type. Put together, these observations support that dietary determinants of hypophosphatemia, leading to increased plasma levels of 1,25-(OH)2-D, could reduce the risk of aging men to develop prostatic diseases, both benign prostatic hyperplasia and CaP.

Advances in the systemic treatment of cancers in the elderly

Cancer is a disease of the elderly. More than 50% of all cancers and deaths occur in people over 65 years. Older cancer patients are less likely to be referred to centers or to be given adequate chemotherapy. The elderly are under-represented in Phase I and II trials. Some of this hesitancy to give chemotherapy is related to the increased presence of co-morbid conditions in the elderly. Toxicity is another concern. This review summarizes data from literature on the effectiveness, outcome, and toxicity of chemotherapy in selected tumors. Information is presented on age related effects. In addition, a summary of new agents and biologics is presented that needs to be looked at for age related effects. Some comments are made on the pharmacokinetic impact of physiologic changes in the elderly on chemotherapy drugs. As the world's population ages, we need to include the elderly in trials to get data on age related effects. Most of the information presented shows that effective chemotherapy can be given safely to the elderly and the outcomes and toxicity are equivalent for many of the common solid tumors.

Breast cancer screening

Breast cancer is the most common malignancy among women in the United States; however, recent data demonstrates a decline in the mortality rate, which may be attributed to early detection from screening programs combined with effective therapies for early stage disease. As a result of the prevalence of breast cancer and its association with highly emotional issues, screening recommendations have aroused debate in the scientific, public, and legislative domains. A general consensus supports breast cancer screening among women between the ages of 50 and 70; however, much controversy exists regarding screening for women age 40 to 49 or above age 70. This article explores the issues involved in determining breast cancer screening recommendations among asymptomatic women with average risk in the United States.

Regulation of G1/S transition and induction of apoptosis in HL-60 leukemia cells by fenretinide (4HPR)

We previously reported that all-trans retinoic acid (RA) and fenretinide (4HPR) suppress HL-60 leukemia cell growth and cause partial cell arrest in the G1-to-S phase. Moreover, 4HPR but not RA induces apoptosis in HL-60 cells. To investigate further the observed biological effects, cyclin D1 and cdk4 expression and the level of phosphorylation of the retinoblastoma protein Rb were assessed. Cyclin D1 and cdk4 expression and Rb phosphorylation were significantly reduced, by 40-75%, after 24 hr of treatment with RA or 4HPR; these decreases were either transient, e.g., only at 24 hr for cdk4, or sustained for 72 hr. In general, more pronounced decreases were seen in the 4HPR-treated cells. Evidence for 4HPR-induced apoptosis comes from (1) cleavage of the enzyme poly(ADP-ribose) polymerase (PARP) to an 89-kDa truncated product, (2) appearance of DNA ladders on agarose gel electrophoresis, and (3) higher incorporation in situ of digoxigenin nucleotides into the free 3'-ends of DNA. Overnight pretreatment with 0.5-5.0 microM of the CPP32 inhibitor DEVD, but not the ICE inhibitor YVAD, significantly reduced the specific processing of PARP, suggesting that CPP32 is involved in the mechanism of action of 4HPR. Analysis of 2 lipid-derived second messengers, ceramide and diacylglycerol (DAG), as a function of time of treatment with RA or 4HPR, showed ceramide but not DAG to be significantly albeit transiently increased 2-fold at 3 hr, by 4HPR. To test further whether ceramide may be involved in the signaling cascade that culminates in the induction of apoptosis in 4HPR-treated HL-60 cells, the effects of fumonisin B1, an inhibitor of ceramide synthase, were studied. Simultaneous treatment of cells with 4HPR and 25-100 microM fumonisin B1 resulted in a dose-dependent reduction in the elevation in ceramide, the extent of PARP cleavage, and induction of apoptosis. Pretreatment with DEVD or YVAD, on the other hand, had no effect on the 4HPR-induced increase in ceramide.

Dietary factors and cancers of breast, endometrium, and ovary: strategies for modifying fat intake in African American women

Modification of dietary fat and fiber could help prevent cancers of the breast, endometrium, and ovary that are prevalent in African-American women. Dietary intervention programs aimed at reducing fat intake have had mixed results in this population. The transtheoretic model is proposed for achieving dietary change. Strategies for changing health behaviors in African-American women include heightening sensitivity to cultural values among health educators and the use of multiple strategies to reinforce messages. To stimulate healthier eating, it is important to incorporate the distinct habitual eating patterns into innovative intervention methods, using effective behavioral change methods.