Malignant plastics

Williams, R. S. (2002). Care of Plastics Malignant plastics. WAAC Newsletter, (January), 24, 1. Available from http //www.palimpsest.stanford.edu/waac/wn/wn24-l/wn24-102.html [Accessed 30 June 2006]. 

In older adults, AML is either more likely to arise from a proximal bone marrow stem cell disorder, such as myelodys-plastic syndrome (MDS), or present as a secondary leukemia resulting from treatment with prior chemotherapy or radiation for an earlier malignancy. These forms of AML are notoriously less responsive to chemotherapy and thus have a lower CR rate and EFS.20... 

Pathophysiologically, this arises in three ways. First, output may be ineffective as occurs with deficiencies of folate and vitamin B12, or in the myelodys-plastic syndromes. Second, extensive infiltration by malignant disease or fibrous is to blame. Third, the blood-forming tissue is deleted - usually reversible... 

In terms of pharmacokinetics, many host factors, such as the route of administration, the metabolism, the catabolism and clearance will considerably determine the antineo-plastic success of a drug. One major difficulty with the clinical effectiveness of chemotherapy of neoplastic diseases is the requirement that it kill malignant tumor cells at doses that allow cells in the patient s vital organs to survive so that the recovery can occur. In other words, it is to obtain a reasonably safe therapeutic index favoring introduction into clinical practice. 

Table 1.1. Retrospective outcome analyses of plastic stents in malignant biliary obstruction...

The choice between a plastic and a metal stent for long-term palliation in patients with unresect-able malignant bihary strictures should be based on life expectancy and the cost of procedures. Patients expected to live more than 6 months should be stented with metal stents to reduce the need for recurrent hospitalization and antibiotic therapy (Prat et al. 1998). If the cost of the metal stent is less than 50% of the cost of ERCP, then the metal stent should be placed at the time of the first ERCP (Yeoh et al. 1999). 

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