Abstract
Aim. To assess the possibility of using empirical models for predicting a second metachronous tumor after chemotherapy of the first one to improve the efficiency of prophylactic medical examination of cancer patients. Material and Мethods. The objects of the study are electronic databases on the chemotherapy treatment of cancer patients, extracts from the database on the treatment of patients with PM oncology for the period 1990–2015, case histories and medical records of 796 patients with metachronous PM oncology: experimental group – 496 patients after chemotherapy, control group – 300 patients after surgical treatment of the first tumor, the sample size was not previously calculated. Results. Empirical models for predicting a second metachronous tumor after chemotherapy of the first one showed the highest probability of a second metachronous tumor in three time intervals: 1256.00–1884.00 days (3.44–5.16 years; HR=2.25; tumor is 69.2 %), 3768.00–4396.00 days (10.32–12.04 years; HR=3.86; chance 79.4 %), 6280.00–6908.00 days (17, 21–18.93 years; HR=2.00; 66.7 % chance. Conclusion. Based on the results of the analysis of empirical risk models for a second metachronous tumor after chemotherapy of the first one, amendments were developed to the timing of dispensary observation of patients with primary multiple metachronous malignant neoplasms after chemotherapy of the first tumor. Knowledge of the most probable timing of the occurrence of a second metachronous tumor after chemotherapy of the first one makes it possible to more accurately draw up and, if necessary, adjust the plan for dispensary observation after chemotherapy treatment of the first tumor.