Mendeley  

Zotero  

Asghari R, Hassan Zadeh A. Application of Phase Distributions in the Aging Process of Patients with Skin Cancer. Iran J Health Insur 2018; 1 (3) :97-104
URL: http://journal.ihio.gov.ir/article-1-40-en.html

Introduction: Skin cancer is one of the most common types of cancers in the United States of America and can be prevented in most cases. Skin cancer significantly affects the quality of life of people and can cause disorder or even death. A review of the aging process of cancer patients, its modeling with physiological age and comparison with normal people is conducted in this paper by using phase-type distributions.
Methods: In this model, it is assumed that the length of any physiological age follows an exponential distribution in a Markov chain environment. In the continuous-time Markov chain, a state is assumed to represent death, and n_x transient states, where x is the patient's age at the time of diagnosis of cancer. Each transient state represents a physiological age and aging is a process of change from a physiological age to the next physiological age to reach the end of the process. There is also an absorbing state that the transition from any state to the absorbing state can take place. In this study, using data of skin cancer patients in the United States, the unknown parameters associated with the aging process were estimated.
Results: The study was conducted on patients with melanoma-related cancer in the United States during the years 1973 to 2014, with aged 60-65 years old. The registered number of melanoma cases was 1,882, of which 1,251 were male (66.5%) and 631 were female (33.5%). A table of parameters for estimating survival probability and related charts for the whole population in the age group and gender is presented.
Conclusions: The fitting results of data modeling are very satisfying. The physiological age parameters were estimated in general that could be useful in estimating the distribution of the phase-type parameters and to calculate the function and the moments. And also the effect of gender on the survival rate of patients was determined which indicates that the survival of males is higher than that of women. On the other hand, the life expectancy of cancer patients has been compared with the entire population of the United States, which was less it was expected.