Measurements of endosteal surface areas in human long bones: relationship to sites of occurrence of osteosarcoma.

Using techniques of bone scanning and ashing, the areas of the endosteal surfaces in cortical and trabecular bone have been determined for the proximal, mid and distal thirds of each of the six long bones of an adult human subject. The relative frequency of occurrence of bone sarcomas, scored as to site, has been analysed in relation to these measured areas. Data on tumour occurrence have been drawn from three sources: radium-case data from Rowland and Keane (33 cases), naturally-occurring cases from series by Sissons (139 cases) and by Dahlin (473 cases). A strong correlation is demonstrated between tumour frequency and trabecular area, but correlation with cortical area is poor. By comparing the tumour frequency in the mid thirds of the bones with the total recorded it has been possible to show that the probability of tumour occurrence per unit area of cortical bone, relative to that of trabecular bone, is 0.16 +/- 0.06. Analysis of the available dose data for the radium cases shows that in this instance dose has not contributed to the observed correlations. The results lend support to the thesis that tumour occurrence depends on surface area, i.e. on the number of cells at risk.