The potential relationships between aging and cancer

Recent Development of Rhenium-Based Materials in the Application of Diagnosis and Tumor Therapy

Rhenium (Re) is widely used in the diagnosis and treatment of cancer due to its unique physical and chemical properties. Re has more valence electrons in its outer shell, allowing it to exist in a variety of oxidation states and to form different geometric configurations with many different ligands. The luminescence properties, lipophilicity, and cytotoxicity of complexes can be adjusted by changing the ligand of Re. This article mainly reviews the development of radionuclide 188Re in radiotherapy and some innovative applications of Re as well as the different therapeutic approaches and imaging techniques used in cancer therapy. In addition, the current application and future challenges and opportunities of Re are also discussed.

New surgical options for elderly lung cancer patients

To understand the size of the aging population in the United States, the imminent need to include the elderly in clinical studies on lung cancer, and the safe potential of video-assisted thoracic surgery, and to change awareness of the elderly's need for and ability to undergo treatment for lung cancer, clinical studies of video-assisted thoracic surgery in patients > or = 70 years of age are presented. The elderly are a fast-growing part of the American population who are at high risk for lung cancer and should be included in clinical studies. Age alone should not be a contradiction to thoracic surgical interventions when video thoracoscopy is performed as treatment.

Short- and intermediate-term carcinogenicity testing--a review. Part 2: available experimental models

Numerous experimental protocols for short- and intermediate-term carcinogenicity assays have been available for many years. This paper surveys various of these test systems in rodents, fish species, non-vertebrates and avian embryos in ovo. The mouse skin tumour assay and the rat liver foci assay were used to introduce the basic concepts of short- and intermediate-term carcinogenicity testing in the previous part of the review. The focus of this second part of the review is on rodent assays for carcinogenicity testing in the lung, kidney, urinary bladder, pancreas, stomach, oral cavity, small intestine, colon, and on the possibility to combine several target organs in multi-organ models. The potential use of various fish species, non-vertebrates and hatching eggs for carcinogenicity testing is outlined and the advantages and limitations are discussed. This review also presents the problem of validation of any carcinogenicity test system and proposes a strategy for contemporary safety assessment of chemicals with regard to the detection and evaluation of carcinogenicity.

Short- and intermediate-term carcinogenicity testing--a review. Part 1: the prototypes mouse skin tumour assay and rat liver focus assay

Carcinogenicity testing is by far the most expensive and time-consuming study type of toxicology. For many years, the lifetime exposure with the maximum tolerated dose in two rodent species has been the gold standard of carcinogenicity testing of pharmaceuticals. Major change was introduced by the Fourth International Conference on Harmonization in July 1997; a chronic rodent bioassay in one species and a short-term carcinogenicity assay are regarded as sufficient for registration. Such requirements provide the opportunity to redirect the vast resources previously spent on the lifetime study in the second species. Numerous experimental protocols for short- and intermediate-term carcinogenicity testing in many target tissues have been available for years. The first part of this review describes the basic principles of short- and intermediate-term carcinogenicity testing using the examples of the widely used mouse skin tumour assay and the rat liver foci assay. In the context of these experimental models, the discrimination and quantification of initiating and promoting activity and the use of preneoplastic lesions as endpoints in carcinogenicity testing are described. The review includes the limitations of the models with regard to the extrapolation from effects observed in animal experiments to a potential exposure of humans.

Biology of aging as related to cancer

The relationship of the biology of aging to cancer in older patients is of importance at several levels. The striking increase of cancer incidence with age may be related to a number of biologic factors. Potential age-related etiologic factors include decreased immune surveillance, longer duration of carcinogenic exposure, increased susceptibility of cells to carcinogens, decreased DNA repair, oncogene activation or amplification, and defects in tumor-suppressor genes. Moreover, at the cellular level, the uncontrolled proliferation characteristic of cancer and the reduced proliferation characteristic of senescence may be "opposite sides of the coin," governed by similar mechanisms of gene regulation. The biologic behavior of neoplasma, once initiated, may vary in different age groups depending on tumor type, immune system status, and alterations in other regulatory factors such as angiogenesis. In the clinical approach to the older cancer patient, attention to age-related biologic changes leading to decreased homeostatic reserve, especially in such areas as the hematopoietic, renal, immune, and cardiovascular systems, is essential to the designing of successful therapies.

The association of age and current world cancer mortality rates in relation to a century of cancer deaths in the U.S

Recent data from a variety of countries and from the individual states in the US show that the annual cancer death rate is highly correlated with the percentage of the population aged 60 or more years. Historical data for the United States over the period 1900-1990 reveal that the percentage of its population > or = 60 yrs increased with a corresponding increase in the annual cancer death rate. When the US data over this time period are viewed against the current world data and the current individual state data there is a striking similarity, thereby demonstrating that the current world and state cancer mortality values provide an accurate historical picture of the US cancer death rate over almost a century.