Those candidacies withered once they headed south for the multiple primaries in larger states.
Development of multiple primaries in cancer survivors may be related to increased awareness or be secondary to previous therapies, and may also be due to shared risk factors, including environment, lifestyle, and inherited genes.
Coding of multiple primaries in the cancer registries followed a common set of rules proposed by the International Association of Cancer Registries and the International Agency for Research on Cancer (IARC) (Muir and Percy, 1991).
Given the multiple primaries in routinely published incidence data, the 'current probability' method is actually estimating the average number of primary tumours per person, rather than the probability of getting cancer, and hence tends to overestimate the lifetime risk of getting cancer for all tumours.
Second, according to the common set of rules proposed by the International Agency for Research on Cancer (IARC), multiple primaries arising in the same site are only to be recorded when the morphology belongs to different groups [ 17].
2 In Western Europe, multiple primaries accounted for 0.7% in a hospital registry in Scotland (1972), 13 6.3% in multiple European cancer registries (1995 1999), 14 and 11.7% in an autopsy series from Sweden (1969).
Demographic data on single versus multiple primaries are shown in Table 1.
For breast, lung and colorectal cancers, within-site multiple primaries are expected; in contrast, for prostate cancer, multiple primaries are not usual.
For the relative risk of any cancer, the first cancer reported for patients with multiple primaries was used in the time to event analysis.
Survival of patients with multiple primaries varies widely in the literature, depending on the method of calculation, primary tumor site, cancer stage, year of initial cancer diagnosis, and time interval between index and second primaries.
Considering that CIMP tumours develop due to epigenetic changes of various genes, our results, together with Lawes's results, suggest that epigenetic changes play an important role in the development of multiple primary cancers in the general population.
