EHPnet: Mad Cow Media

Growth is one of the most intrinsic properties of cancer, and the diversity of growth or growth rate has a great influence upon the survival of the host. Since the first radiological measurement of the growth rate of human pulmonary neoplasms by Collins et al. (1956), many investigators reported tumour doubling time as a significant indicator for evaluating lung cancer (Schwartz, 1961; Weiss, 1974; Geddes, 1979; Mizuno et al., 1984). The measurement of tumour doubling time based on the tumour growth represented in serial chest X-ray films, however, is not always applicable to all patients with lung cancer. Irregular shapes or hazy outlines of tumours occasionally make it impossible to accurately calculate tumour size. Also, a very small increase in diameter between sequential chest X-ray films of a slow growing tumour also makes it difficult to obtain an accurate tumour doubling time. More recently, therefore, biochemical measurement of the thymidine kinase and the uridine kinase concentrations in biopsy samples has been instituted by Greengard et al. (1985) as a method of supplying a dynamic parameter for predicting tumour doubling time in lung cancer, and as an accurate procedure to compensate for the shortcomings of radiological measurement. On the other hand, Togawa et al. (1985) reported that lung cancer could be classified into two major groups based on the differences in 201TI to 67Ga uptake ratio by the tumour using quantitative 201TI and 67Ga scans. About two-thirds of lung cancers studied, mainly epidermoid and small cell carcinomas, took up much more 67Ga than 201TI, while for the other one-third, mostly adenocarcinomas, the reverse was the case. A further point worth noting was that the uptake of both nuclides varied and occasionally showed contrary patterns even in patients belonging to the same category at the light microscopic level. While the exact mechanism of 201T1 and 67Ga accumulations