Biochemical and imaging surveillance in germline TP53 mutation carriers with Li-Fraumeni syndrome: 11 year follow-up of a prospective observational study

Abstract

Background: Carriers of a germline TP53 pathogenic variant have a substantial lifetime risk of developing cancer. In 2011, we did a prospective observational study of members of families who chose to either undergo a comprehensive surveillance protocol for individuals with Li-Fraumeni syndrome or not. We sought to update our assessment of and modify the surveillance protocol, so in this study we report both longer follow-up of these patients and additional patients who underwent surveillance, as well as update the originally presented surveillance protocol.

Methods: A clinical surveillance protocol using physical examination and frequent biochemical and imaging studies (consisting of whole-body MRI, brain MRI, breast MRI, mammography, abdominal and pelvic ultrasound, and colonoscopy) was introduced at three tertiary care centres in Canada and the USA on Jan 1, 2004, for carriers of TP53 pathogenic variants. After confirmation of TP53 mutation, participants either chose to undergo surveillance or chose not to undergo surveillance. Patients could cross over between groups at any time. The primary outcome measure was detection of asymptomatic tumours by surveillance investigations. The secondary outcome measure was 5 year overall survival established from a tumour diagnosed symptomatically (in the non-surveillance group) versus one diagnosed by surveillance. We completed survival analyses using an as-treated approach.

Findings: Between Jan 1, 2004, and July 1, 2015, we identified 89 carriers of TP53 pathogenic variants in 39 unrelated families, of whom 40 (45%) agreed to surveillance and 49 (55%) declined surveillance. 19 (21%) patients crossed over from the non-surveillance to the surveillance group, giving a total of 59 (66%) individuals undergoing surveillance for a median of 32 months (IQR 12-87). 40 asymptomatic tumours have been detected in 19 (32%) of 59 patients who underwent surveillance. Two additional cancers were diagnosed between surveillance assessments (false negatives) and two biopsied lesions were non-neoplastic entities on pathological review (false positives). Among the 49 individuals who initially declined surveillance, 61 symptomatic tumours were diagnosed in 43 (88%) patients. 21 (49%) of the 43 individuals not on surveillance who developed cancer were alive compared with 16 (84%) of the 19 individuals undergoing surveillance who developed cancer (p=0·012) after a median follow-up of 46 months (IQR 22-72) for those not on surveillance and 38 months (12-86) for those on surveillance. 5 year overall survival was 88·8% (95% CI 78·7-100) in the surveillance group and 59·6% (47·2-75·2) in the non-surveillance group (p=0·0132).

Interpretation: Our findings show that long-term compliance with a comprehensive surveillance protocol for early tumour detection in individuals with pathogenic TP53 variants is feasible and that early tumour detection through surveillance is associated with improved long-term survival. Incorporation of this approach into clinical management of these patients should be considered.

Funding: Canadian Institutes for Heath Research, Canadian Cancer Society, Terry Fox Research Institute, SickKids Foundation, and Soccer for Hope Foundation.