Feasibility of whole-body MRI for cancer surveillance in children and young people with Ataxia Telangiectasia

Abstract

Ataxia Telangiectasia (A-T) is an autosomal recessive disorder characterised by cerebellar degeneration, immunodeficiency, respiratory disease, radiosensitivity, and cancer susceptibility. A-T is a progressive condition that manifests in early childhood. The life expectancy of people with A-T is estimated to be 25 years, with cancer being the most frequent reason for mortality. Cancer in A-T has been reported as early as two years old, with a median age of diagnosis of 12.5 years. Despite the high cancer risk that people with A-T experience (22-24% cumulative incidence up to age 20 years), current guidelines for management of children and young adults with A-T do not include cancer surveillance. An international consensus statement regarding screening in Cancer Predisposition Syndromes (CPS) noted that ‘Evidence-based standards for cancer screening do not exist for patients with A-T, particularly in childhood.’ In fact, the only recommendation made is consideration of: ‘Annual physical exam, complete blood count, and complete metabolic profile including lactate dehydrogenase.’ Developments in magnetic resonance imaging (MRI) technology allow whole-body (WB-) MRI scans to be performed with relatively short acquisition times. WB-MRI protocols optimised for cancer detection are used clinically for diagnosing and monitoring sarcomas, metastases and haematological tumours like myeloma. Previous trials have explored the use of WB-MRI along with other diagnostic tests to develop guidelines for cancer surveillance in CPS. The excellent soft-tissue contrast resolution and ability to demonstrate malignancy contribute to the increased interest in including this technique in cancer surveillance protocols. However, it is important to consider the challenges associated with this technique, such as the relatively long imaging times and image artefacts caused by motion, which may require the use of sedation or general anaesthesia in young children. The high sensitivity of MRI might detect incidental findings (false positives), which could lead clinicians to request unnecessary examinations. Nevertheless, trials of cancer surveillance in other CPS like A-T that include WB-MRI have demonstrated the feasibility of the approach, with significantly improved survival (thus better outcomes) to the extent that WB-MRI is now incorporated into clinical guidelines. The lack of ionising radiation in MRI makes this an attractive approach for imaging-based cancer surveillance in people with A-T, but this approach has not yet been systematically evaluated or incorporated into guidelines for people with A-T. In practice, WB-MRI would be combined with blood tests (e.g. to pick up leukaemia) in a surveillance programme. People with A-T and their families already have the worry of living with a chronic life-limiting childhood-onset disease with a poor overall prognosis and progressive physical disability. A cancer surveillance programme could add to this burden with a detrimental effect on both the child with A-T and their family members. It is recognised that surveillance tests can increase anxiety due to the possibility of finding cancer or other pathologies. Any plan to initiate a cancer surveillance programme needs to carefully consider this psychological burden. Therefore, before addressing the current lack of evidence-based guidelines through a formal prospective trial, we first need to know whether cancer surveillance in children and young people with A-T using whole-body MRI is feasible and desirable. The purpose of this research project is to address the following primary aim: • To establish the technical feasibility of whole-body MRI for cancer surveillance in children and young people with A-T and secondary aims: • To establish the prevalence and spectrum of cancer and non-cancer abnormalities detected on whole-body MRI in this population • To establish views of, and psychological impact on, participants and families/carers in response to participating in whole-body MRI for cancer surveillance. • To establish the feasibility of conducting a formal screening trial in terms of statistical design, sample size, screening interval, comparator arms and international collaboration. • To establish the current practice regarding cancer surveillance in children and young people with A-T across international centres.