Empirical models for predicting the secondary metachronous tumor after chemoradiation therapy of the primary tumor in the clinical examination of cancer patients

Evaluation of the possibility of applying empirical models for predicting a secondary metachronous tumor after chemoradiation therapy of the primary tumor in order to increase the efficiency of cancer patients medical examination were presented. This is the retrospective research based on archived data of the Chelyabinsk Regional Clinical Center of Oncology and Nuclear Medicine (GBUZ «CHOKZO and YAM», Chelyabinsk). The subjects of the research are medical records, medical and radiation maps, electronic databases on chemoradiation therapy of cancer patients in BSSC «CHOKZO and YAM», unloading from the database on treatment of patients with PM ZOH for the period 1990-2015. The study group contained 168 patients after chemoradiation therapy and a control group of 300 patients after surgery of the primary tumor. Models for prediction of the secondary metachronous tumor were constructed with the use of the module «Analysis of survival STATISTICA» («Statistica Version 10.0.0.0») and multi-factor analysis (Cox model), all complications that led to changes in treatment (scheme, interval between courses) were taking into account. The compliance of the empirical model with the results of the study was tested by the chi-square criterion (c²). On average, the patients received 2.83 courses of chemotherapy and 1.15 courses of radiation therapy, the duration of chemotherapy and radiation therapy was 3.37 months and 1.87 months respectively. The duration of the interval between treatments was 2.33 months and 1.30 months, respectively. Complications of chemoradiotherapy were reported in 80 patients (47.6%). Our empirical models for predicting the secondary metachronous tumor after chemoradiation therapy of the primary tumor demonstrated the highest probability of the secondary metachronous tumor development in five time intervals: 3,804.09-4,564.91 days (10.42-12.51 years) for chemotherapy HR=2.14; risk 68.2%; for radiation therapy HR=2.00; risk 66.7%), 6,847.36-7,608.18 days (18.76-20.84 years; for chemotherapy HR=1.75; risk 63.6%; for radiation therapy HR=1.91; risk 65.6%), 7,608.18-8,369.00 days (20.84-22.93 years; for chemotherapy HR=1.71; risk 63.1%; for radiotherapy HR=1.67; risk 62.5%); 3,043.27-,3804.09 days (8.34-10.42 years; for radiotherapy HR=1.92; chance 65.9%; for chemotherapy HR=1.35; risk 57.45%) and 5,325.73-6,086.55 (14.59-16.67 years; for radiation therapy HR=2.00; risk 66.70%; for chemotherapy HR=1.56; risk 60.94%). The knowledge of the timing of the second metachronous tumor after chemoradiation therapy of the primary tumor makes it possible to draw up more precisely and, if necessary, adjust the plan of outpatient observation individually for each cancerl patient after chemoradiation treatment of the first tumor.