Qom University of Medical Sciences Journal

Introduction
Cancer is the abnormal division of cells. The progress of medical science in knowing the causes and mechanism of this disease has led to its early diagnosis. Biochemical risk factors (alkylating drugs, benzene ring), biophysical factors (ionizing rays, sunlight), biological factors (viruses and bacteria), genetic syndromes  (Down syndrome, neurofibromatosis type І), immune deficiencies (congenital ataxia-telangiectasia and neutropenia) play a role in its occurrence. Leukemia is the most common malignancy in children (30%). Multifactorial factors such as father’s occupation, parents’ smoking during pregnancy, living in the tropical areas, and history of viral diseases such as mumps and chicken pox have a role in its development. This study aims to determine the effective factors in 5-year survival of children with leukemia in Iran.
Methods
This retrospective cohort study was conducted on 196 children diagnosed with acute myeloid leukemia (AML) and acute lymphocytic leukemia (ALL) admitted to the Oncology Department of Hazrat-e Masoumeh Hospital in Qom, Iran from 2017 to 2023. Census sampling method was used to select samples. Inclusion criteria were hospitalization due to AML and ALL. The exclusion criteria were the diagnosis of other types of cancer and unwillingness to complete the questionnaire. A 99-item questionnaire with two “children” and “parents” sections was completed through a phone call with the families of children. Each section surveyed demographic information, history of disease and lifestyle. Different data including age, gender, nationality, place of residence, blood group, Rhesus (Rh) factor, etc. were recorded. The questionnaire was designed based on the first part of TNO-AZL preschool children quality of life (TAPQOL) questionnaire.
After completing the questionnaire and extracting information, data analysis was performed using the Kaplan-Meier method and log-rank test and data modeling was performed using the Cox regression model and the Log-Log method in STATA software, version 21 The significance level was set at 0.05.
Results
There were 126 children with AML (64.3%) and 70 with ALL (35.7%). Children included 113(57.7%) boys and 83(42.3%) girls; 179(91.3%) from cities and 17(8.7%) villages; 54(27.6%) with blood group A, 34(17.3%) with blood group B, 18(9.2%) with blood group AB, 62(31.6%) with blood group O, and 27(13.8%) with unknown blood group. The 5-year survival rate was significantly different in terms of blood group (P=0.011).
The Rh factor of 154(78.6%) were positive, 19(9.7%) negative and 28(14.3%) unknown. The 5-year survival rate was significantly different in terms of Rh factor  (P=0.016).
Moreover, 104(53.1%) had a family history of cancer and 92(46.9%) had no history. The parents of 63 children (32.1%) were relatives and 133 children (67.9%) had non-relative parents. Fathers of 53 children (27%) were workers, 86(43.9%) self-employed, and 55(28%) employed. Mothers of 183 children (93.4%) were housewives and 10(5.1%) employed. Fathers of 40 children (20.4%) had elementary school education, 42(21.4%) middle-school education, 49(25%) high school diploma, and 65(33.2%) university education. Mothers of 50 children (25.5%) had elementary school education, 32(16.3%) middle school education, 73(37.3%) high school diploma, and 41(20.9%) university education. Frequency of smoking in parents, 40(20.4%) children answered always (daily), 15(7.7%) most of the time (weekly), 18(9.2%) sometimes  (monthly), 3(1.5%) rarely (once every few months) and 120(61.2%) never. The family income of 111 children (56.6%) was low, 76(38.8%) moderate, and 8(4.1%) good (ability to provide medicine and treatment). With the Cox regression model, the survival rate decreased over time; after 120 months since the diagnosis of AML and ALL, the survival rate went from 1 to 0.5. The chance of survival in ALL group (102±59.4 months) was higher than in the AML group (81.5±44.2 months).
Conclusion
In children with AML and ALL from Qom City, gender was effective in the incidence and response to treatment; the incidence was lower in girls and their death rate was lower compared to boys. Most of the children were male (57.7%), living in the city (91.3%) with blood group O (31.6%), Rh factor positive (78.6%), family history of cancer (53.1%), with no history of bone marrow transplant (93.9%), self-employed fathers (43.9%), housekeeper mothers (88.3%), college-educated fathers  (33.2%), diploma mothers (34.2%), low family income level (56.6%), and non-smoker parents (61.2%). The number of children with AML in Qom City is higher than that of children with ALL (64.3% vs 35.7%). This suggests the existence of predisposing factors for this type of disease in the region.
Ethical Considerations
Compliance with ethical guidelines
The study was approved by the Ethics Committee of Qom University of Medical Sciences, Qom, Iran (Code: IR.MUQ.REC.1400.137). After explaining the study objectives, the informed consent of parents was obtained.
Funding
This study was financially supported by Qom University of Medical Sciences, Qom, Iran.
Authors contributions
All authors equally contributed to preparing this article.
Conflicts of interest
The authors declared no conflict of interest.
Acknowledgments
The authors would like to thank the Vice-Chancellor for Research and Technology of Qom University of Medical Sciences, Qom, Iran for the financial support.