The Collaborative Group on Hormonal Factors in Breast Cancer has brought together and reanalysed about 90% of the worldwide epidemiological evidence on the relation between risk of breast cancer and use of hormone replacement therapy (HRT).

The risk factors for venous thrombosis differ from those for arterial vascular disease. During the past 5 years, knowledge about the aetiology of venous thrombosis has advanced with the discovery of several factors that contribute to the incidence of thrombosis, particularly the role of coagulation abnormalities. These abnormalities are common in the general population and therefore will be present simultaneously in some individuals. The resultant gene-gene and gene-environment interactions between risk factors are the key to the understanding of why a certain person develops thrombosis at a specific point in time.

Delayed presentation of symptomatic breast cancer is associated with lower survival. Understanding of the factors that influence delay is important for the development of strategies to shorten delays. We did a systematic review to assess the quality and strength of evidence on risk factors for delays by patients and providers.

Most patients with breast cancer are detected after symptoms occur rather than through screening. The impact on survival of delays between the onset of symptoms and the start of treatment is controversial and cannot be studied in randomised controlled trials. We did a systematic review of observational studies (worldwide) of duration of symptoms and survival.

This paper charts the development of haemodialysis, the cornerstone of renal replacement therapy (RRT). It has enabled patients with end-stage renal failure to survive for years, in many cases with a surprisingly good quality of life. Through technological advances, RRT can be offered to patients who are older and more frail. Many have intercurrent comorbid illness. Such patients can have good quality of life, but their survival is shorter since they are likely to succumb early to comorbid illnesses. The challenge to nephrologists is to provide treatment based on exacting standards for all those patients who can benefit, yet to maintain cost-effectiveness. There is increasing recognition that, however good the technology underpinning dialysis, what justifies the cost and commitment that dialysis entails is the provision for the patient of a satisfactory quality of life.

Leprosy is an ancient disease which is still poorly understood and often feared by the general public and even by some healthcare professionals. Fortunately, improvements in the management of leprosy over the past three decades have diminished the stigma and greatly altered the outlook for patients. Public understanding of the disease has benefited from WHO's goal of eliminating leprosy as a public health problem by the year 2000. Unfortunately that goal has also led many to believe that leprosy has been or will soon be eradicated. This will not happen in the near future because, despite a fall in registered cases, the incidence of the disease has changed very little, and eradication of a bacterial infectious disease such as this is unlikely with chemotherapy alone. Nevertheless, as a result of the WHO's efforts, patients nearly everywhere should have access to care, and the incidence may begin to diminish if adequate control efforts are maintained beyond the year 2000. Given the mobility of patients today a physician anywhere may occasionally see a case or be asked about the disease so a basic understanding of leprosy and its management should prove useful.

Menopause is diagnosed after 12 months of amenorrhoea resulting from the permanent cessation of ovarian function. The mean age at menopause is 51 years. The perimenopause, a time of changing ovarian function, precedes the final menses by several years. The physiology and clinical manifestations of this transition to menopause are not well understood; however, some symptoms, such as hot flashes, certainly begin in the perimenopause. Causal associations between menopause and several symptoms and diseases are proposed. The evidence for these associations varies and is reviewed. Hormone replacement therapy can be directed at symptom relief or at prevention or treatment of chronic diseases. Doses and routes of hormone replacement therapy vary by indication. Complications of hormone replacement therapy depend on the regimen used. Knowing the expected vaginal bleeding pattern for each hormone replacement therapy regimen is important, since unexpected bleeding may signal endometrial hyperplasia. Postmenopausal hormone therapy is a complex intervention that produces positive and negative specific health effects. Overall, based on observational studies, postmenopausal women who use hormones have a 30-50% lower all-cause mortality rate than those who do not use hormones. It is important to recognise that the value that individual women place on various health outcomes associated with hormone replacement therapy may differ. Thus, the decision to use hormone replacement therapy should be made jointly by each woman and her health-care provider, after careful consideration of possible benefits, risks, and her personal preferences.