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Breast Cancer after Prophylactic Bilateral Mastectomy in Women with a BRCA Mutation
Women with a mutation of the BRCA1 or BRCA2 gene are highly susceptible to breast cancer. This study assessed the incidence of breast cancer among 139 such women who chose to undergo prophylactic mastectomy or regular surveillance. After a follow-up of three years, breast cancer developed in 8 of 63 women in the surveillance group but in none of the 76 women who underwent prophylactic mastectomy.
This prospective investigation strengthens the case for prophylactic mastectomy in women who have a mutation of the BRCA1 or BRCA2 breast-cancer-susceptibility gene. The limitation of the study is the relatively brief follow-up. In the short run, the procedure is highly effective, but it is not known whether cancer will develop in residual breast tissue years later. Despite this shortcoming, the study provides useful information for clinicians counseling women with a high risk of breast cancer.
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Three Months versus One Year of Oral Anticoagulant Therapy for Idiopathic Deep Venous Thrombosis
The optimal duration of oral anticoagulant therapy for a first episode of idiopathic deep venous thrombosis is unknown. In this study, patients were randomly assigned to receive such therapy for either 3 months or 12 months. After 12 months, the group that had continued to receive an oral anticoagulant had a lower rate of recurrence of deep venous thrombosis. However, after 24 months of follow-up, the rate of recurrence was indistinguishable in the two groups.
In patients with deep venous thrombosis of unknown cause, extending oral anticoagulant therapy to 12 months is beneficial; this benefit is lost, however, after therapy is discontinued. It is possible that the continuation of oral anticoagulant therapy indefinitely could extend the clinical benefit, but at the risk of continued bleeding complications.
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Treatment of Multidrug-Resistant Tuberculosis
At a referral hospital in Istanbul, 158 patients received treatment for multidrug-resistant tuberculosis between 1992 and 1999. All patients had evidence of resistance to both isoniazid and rifampin, and 40 percent of patients had extensive disease. The mean number of drugs administered was 5.5, and surgery was performed in 36 patients. The overall success rate was 77 percent, with cures in 78 patients and probable cures in 43.
This study shows that, with intensive treatment and prolonged hospitalization, most patients with multidrug-resistant tuberculosis can be cured. However, multidrug-resistant disease is largely the result of inappropriate and poorly supervised primary treatment of tuberculosis.
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Defective Urinary Concentrating Ability Due to a Complete Deficiency of Aquaporin-1
Aquaporin-1 is a water-channel protein expressed on red-cell membranes (where it is associated with the Colton blood-group antigen), proximal tubular epithelium, and other renal structures. Persons who lack the Colton blood-group antigen are homozygous for mutations in the aquaporin-1 gene that disrupt the production of the protein. Two women with a complete deficiency of aquaporin-1 were found to have impaired ability to concentrate their urine maximally when deprived of water.
The effects of this germ-line mutation demonstrate that aquaporin-1 has a role in concentrating the urine during water deprivation.
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The Influence of Hospital Volume on Survival after Resection for Lung Cancer
In this study of elderly patients who underwent resection for lung cancer, the likelihood of a good outcome was highest if surgery was performed in a hospital with a high volume of such procedures. The probability of surviving for five years after lung-cancer surgery at hospitals with the highest volume was 44 percent, as compared with 33 percent if the surgery was performed at hospitals with the lowest volume.
It is known that the outcome of surgery for cancer is often better in hospitals where many such operations are performed, but the relation between the volume of procedures and outcome has been uncertain in the case of lung cancer. This study shows that the results of lung-cancer surgery are best in hospitals where many such operations are performed annually.
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Medical Progress: Management of Tuberculosis in the United States
Despite a resurgence of tuberculosis in the late 1980s and early 1990s, renewed attention to this public health problem has brought the incidence of tuberculosis to an all-time low in the United States. We now have the opportunity to control or eliminate the disease. This review article focuses on the epidemiologic features of tuberculosis, case identification, treatment of active and latent infection, and special situations such as treatment of patients with human immunodeficiency virus infection and those infected with drug-resistant organisms.
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