Even if there are evidences that the risk of obesity is higher for patients treated on older protocols which included cranial irradiation, also children treated with more modern protocols experienced weight gain. Patients not irradiated could be considered a tool to distinguish the effects caused by radiotherapy from those caused by chemotherapy. Vaisman showed already in 1993 that specific form of chemotherapy, like methotrexate and 6-mercaptopurine, affects metabolic fuel utilization and protein synthesis and turnover, altering body composition [
33]. In 1998 Birkebaek and Clausen observed weight gain during the ALL treatment period indicating that chemotherapy could be a major factor in the etiology of weight gain during treatment [
34]. In contrast, before the end of the treatment, some evidences of recovery of BMI SDS to baseline levels were documented [
35]. In 2003 Oeffinger and colleagues published data documenting that no chemotherapeutic agent, either individually or in combination, was significantly associated with overweight and obesity in ALL survivors during and after treatment [
27]. Long-term BMI data in an unirradiated population are not yet fully described and, as well as short-term data, they are extrapolated from small population. In 1995, Ventham and colleagues examined changes in BMI SDS up to 6 years after diagnosis in 126 ALL patients diagnosed between 1990 and 1997. They were not treated with cranial irradiation (UK ALL XI protocol). There was a significant increase in BMI SDS from diagnosis to 3 years after it in 59 ALL patients and the prevalence of obesity increased from 1.7% at diagnosis to 15.3% at 3 years after diagnosis [
36]. In the study of Craig and colleagues unirradiated patients had raised BMI Z score at the latest follow-up (more than 4 years after the end of treatment) [
23]. The rate of weight gain varies between studies: Garmey and colleagues reported a percentage of obesity, after few years from chemotherapy for ALL, varying between the 15% and 22% and the 9.1% and 19.9% in males and females, respectively [
37]. Razzouk in 2007 documented that 33.7% of 101 young adults treated previously with chemotherapy-alone for ALL were obese [
38]. In 2003 Dalton and colleagues evaluated the long-term (median follow-up time from diagnosis of ALL 6.1 years) weight changes in 618 ALL children treated with different CNS therapies: intrathecal therapy alone, intrathecal therapy with conventional cranial irradiation or intrathecal therapy with twice-daily radiation. Children younger than 13 years at diagnosis had a statistically significant increase in their BMI z scores, regardless of CNS therapy they received [
39]. The same results were achieved by Van Dolgen-Melman [
7] and Razzouk and colleagues [
38]. The first group documented that BMI increased both in patients treated with cranial irradiation and in patients treated without irradiation but with higher intracranial methotrexate doses [
7]. Razzouk, reporting the results of a retrospective longitudinal study performed in 456 children with a new diagnosis of ALL or lymphoma and enrolled into a single protocol, did not find a significant difference in BMI between patients who received radiation and those who did not [
38]. Recently, Murray and his group report data from a retrospective long-term follow-up of 77 patients with a diagnosis of ALL at a median age of 4.6 years, treated on UKALL XI protocol (without cranial irradiation as standard therapy). Recording height and weight of each enrolled patient annually from diagnosis of ALL until 3 years after the end of chemotherapy, they documented that in the whole group BMI-SDS increased from the beginning of the treatment and was still raised at the time of last visit with a difference between genders: in males, BMI-SDS was transient, recovering by the second years after the end of chemotherapy, whereas in females BMI increases did not appear until the end of the treatment, but then it persisted until the last follow-up visit [
40]. In the unirradiated cohort from Cambridge, the frequency of overweight and obesity, as determined by world health organization (WHO) standards, approaches 50% 3 years after the end of chemotherapy (
vs. 30% at diagnosis)[
40].