title: Invariant Characteristics of Carcinogenesis.
abstract: Carcinogenic modeling is aimed at mathematical descriptions of cancer development in aging. In this work, we assumed that a small fraction of individuals in the population is susceptible to cancer, while the rest of the population is resistant to cancer. For individuals susceptible to cancer we adopted methods of conditional survival analyses. We performed computational experiments using data on pancreatic, stomach, gallbladder, colon and rectum, liver, and esophagus cancers from the gastrointestinal system collected for men and women in the SEER registries during 1975-2009. In these experiments, we estimated the time period effects, the birth cohort effects, the age effects and the population (unconditional) cancer hazard rates. We also estimated the individual cancer presentation rates and the individual cancer resistance rates, which are, correspondingly, the hazard and survival rates conditioned on the susceptibility to cancer. The performed experiments showed that for men and women, patterns of the age effects, the individual cancer presentation rates and the individual cancer resistance rates are: (i) intrinsic for each cancer subtype, (ii) invariant to the place of living of the individuals diagnosed with cancer, and (iii) well adjusted for the modifiable variables averaged at a given time period. Such specificity and invariability of the age effects, the individual cancer presentation rates and the individual cancer resistance rates suggest that these carcinogenic characteristics can be useful for predictive carcinogenic studies by methods of inferential statistics and for the development of novel strategies for cancer prevention.
authors.affiliation: Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, Nebraska, United States of America; College of Public Health, University of Nebraska Medical Center, Omaha, Nebraska, United States of America.
authors.forename: Simon
authors.initials: S
authors.lastname: Sherman
authors.affiliation: Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, Nebraska, United States of America; College of Public Health, University of Nebraska Medical Center, Omaha, Nebraska, United States of America.
authors.forename: Nirosha
authors.initials: N
authors.lastname: Rathnayake
authors.affiliation: School of Natural Sciences and Engineering, Ilia State University, Tbilisi, Georgia.
authors.forename: Tengiz
authors.initials: T
authors.lastname: Mdzinarishvili
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D063646:Carcinogenesis; D003198:Computer Simulation; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000175:diagnosis* / Q000453:epidemiology* / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D018426:SEER Program