The growth of a cancer

The growth of a cancer

If it is accepted that a cancer starts from a single transformed cell then it is possible, using straightforward arithmetic, to describe the progression from a single cell to a mass of cells large enough to kill the host. The division of a cell produces two daughter cells. The relationship 2 n will describe the number of cells produced after n generations of division. There 13 14 are between 10 and 10 cells in a typical human being. A 9 tumour 10 /uni00A0 mm in diameter will contain about 10 cells. Since 30 9 /uni00A0/uni00A0 2 = 10 this implies that it would take 30 generations to reach 45 /uni00A0 the threshold of clinical detectability and, as 2 = /uni00A0 3 /uni00A0×/uni00A0 10 will take fewer than 15 subsequent generations to produce a tumour that, through sheer bulk alone, would be fatal. This is an oversimplification because cell loss is a feature of many cancers: for squamous cancers as many as 99% of the cells produced may be lost, mainly by exfoliation. It will, in the presence of cell loss, take many cellular divisions to produce a clinically evident tumour. The growth of a typical human tumour can be described by an exponential relationship, the doubling time of which increases exponentially – so-called Gompertzian growth ( Figure 12.2 ). The growth of a cancer

If it is accepted that a cancer starts from a single transformed cell then it is possible, using straightforward arithmetic, to describe the progression from a single cell to a mass of cells large enough to kill the host. The division of a cell produces two daughter cells. The relationship 2 n will describe the number of cells produced after n generations of division. There 13 14 are between 10 and 10 cells in a typical human being. A 9 tumour 10 /uni00A0 mm in diameter will contain about 10 cells. Since 30 9 /uni00A0/uni00A0 2 = 10 this implies that it would take 30 generations to reach 45 /uni00A0 the threshold of clinical detectability and, as 2 = /uni00A0 3 /uni00A0×/uni00A0 10 will take fewer than 15 subsequent generations to produce a tumour that, through sheer bulk alone, would be fatal. This is an oversimplification because cell loss is a feature of many cancers: for squamous cancers as many as 99% of the cells produced may be lost, mainly by exfoliation. It will, in the presence of cell loss, take many cellular divisions to produce a clinically evident tumour. The growth of a typical human tumour can be described by an exponential relationship, the doubling time of which increases exponentially – so-called Gompertzian growth ( Figure 12.2 ). The growth of a cancer

If it is accepted that a cancer starts from a single transformed cell then it is possible, using straightforward arithmetic, to describe the progression from a single cell to a mass of cells large enough to kill the host. The division of a cell produces two daughter cells. The relationship 2 n will describe the number of cells produced after n generations of division. There 13 14 are between 10 and 10 cells in a typical human being. A 9 tumour 10 /uni00A0 mm in diameter will contain about 10 cells. Since 30 9 /uni00A0/uni00A0 2 = 10 this implies that it would take 30 generations to reach 45 /uni00A0 the threshold of clinical detectability and, as 2 = /uni00A0 3 /uni00A0×/uni00A0 10 will take fewer than 15 subsequent generations to produce a tumour that, through sheer bulk alone, would be fatal. This is an oversimplification because cell loss is a feature of many cancers: for squamous cancers as many as 99% of the cells produced may be lost, mainly by exfoliation. It will, in the presence of cell loss, take many cellular divisions to produce a clinically evident tumour. The growth of a typical human tumour can be described by an exponential relationship, the doubling time of which increases exponentially – so-called Gompertzian growth ( Figure 12.2 ).