Screening of cancer predisposition syndromes

Pediatric patients with cancer predisposition syndromes are at increased risk of developing malignancies compared with their age-matched peers, necessitating regular surveillance. Screening protocols differ among syndromes and are composed of a number of elements, imaging being one. Surveillance can be initiated in infants, children and adolescents with a tumor known or suspected of being related to a cancer predisposition syndrome or where genetic testing identifies a germline pathogenic gene variant in an asymptomatic child. Pre-symptomatic detection of malignant neoplasms offers potential to improve treatment options and survival outcomes, but the benefits and risks of screening need to be weighed, particularly with variable penetrance in many cancer predisposition syndromes. In this review we discuss the benefits and risks of surveillance imaging and the importance of integrating imaging and non-imaging screening elements. We explore the principles of surveillance imaging with particular reference to whole-body MRI, considering the strategies to minimize false-negative and manage false-positive whole-body MRI results, the value of standardized nomenclature when reporting risk stratification to better guide patient management, and the need for timely communication of results to allay anxiety. Cancer predisposition syndrome screening is a multimodality, multidisciplinary and longitudinal process, so developing formalized frameworks for surveillance imaging programs should enhance diagnostic performance while improving the patient experience.

[Genetic basis of subsequent malignant neoplasms]

Subsequent malignant neoplasms (SMNs) are one of the most serious late complications in pediatric patients with cancer, with more than 10% of long-term cancer survivors developing SMNs. Germline mutations in cancer predisposition genes have been recently highlighted as a risk factor. For example, germline mutations in the TP53 gene were reported to be a risk factor for SMNs. A comprehensive genomic analysis for a large cohort of long-term survivors of childhood cancer showed that variants in cancer predisposition genes were correlated with the higher cumulative incidence of SMNs. As another genetic risk, previous reports suggested that polymorphisms in genes regulating thiopurine pathway such as TPMT gene might contribute to SMN development after acute lymphoblastic leukemia treatment. Considering improved survival probability, attention should be paid for late complications. Thus, therapeutic strategy should be optimized based on a risk for SMNs of each individual.

[Subsequent malignancies after long-term follow-up of pediatric hematopoietic stem cell transplantation]

INTRODUCTION

Survival after hematopoietic stem cell transplantation has improved dramatically in recent years. Unfortunately, there is an increased risk of subsequent malignant neoplasms (SMN) in this population and this represents a significant cause of late mortality.

PATIENTS AND METHODS

In this study, we analyzed the incidence of SMN and the associated risk factors in patients referred at a pediatric age for hematopoietic stem cell transplantation (allogeneic or autologous) in our center.

RESULTS

We observed 19 cases of SMN in a cohort of 371 patients, with a cumulative incidence of 6, 12, and 36% at 15, 20, and 30 years of follow-up, respectively. The solid tumors were the most prevalent malignancies. The risk was significantly higher than expected in the general population for each tumor type and in the different age ranges (p<.0001). Radiotherapy and chronic GvHD were the main risk factors for the development of SMN in our series.

CONCLUSIONS

We observed a high incidence of SMN among hematopoietic stem cell transplantation survivors highlighting the need for life-long surveillance.