Introduction

Li-Fraumeni Syndrome (LFS) is an autosomal dominant genetic condition. This means that inheriting just one copy of the mutated or altered gene is enough for a person to be affected by the condition. TP53 mutations are observed in 50-90% of individuals with the condition, signalling defective responses to tumour suppression. LFS is a condition associated with an increased risk of developing a range of different cancers, often at a younger age. Multiple primary cancers can also be experienced in a person’s lifetime.^1,2

Considering the condition cannot be prevented, several studies have investigated the role of surveillance in supporting quality of life. These studies have shown that an increase in screening methods, combined with continuous examinations, shows a benefit in detecting tumours early. Early intervention is associated with higher overall survival rates, as treatment is often initiated at the pre-malignant stage, where it is generally more successful. This is especially important as different people present with different types of tumours, and at various ages. But how often should people be screened for cancer? And what cancers should they be screened for?^1,2

Understanding li-fraumeni syndrome

LFS is a rare condition that presents in 1 in 3,000-10,000 people, with an increased prevalence in some ethnic groups and populations. 70-90% of those with the condition have a lifetime risk of developing a cancer, and 50% of those develop a cancer under the age of 40. Diagnosis of the condition is conducted via clinical criteria and molecular genetic testing.¹  

In most cases, LFS is caused by an inherited mutation in TP53. TP53 is a tumour-suppressor gene that responds to cellular stress by regulating the activation and suppression of other genes involved in tumour suppression. This includes the DNA damage response pathway. Accumulation of the mutant or defective protein p53 leads to uncontrolled cell growth and genomic instability. For example, cells with damaged DNA are able to grow uncontrollably and bypass mechanisms that would normally repair DNA. The uncontrolled growth increases the risk of developing tumours and several cancers, which are characteristic of LFS. Studies have found over 250 alterations of the gene that could lead to LFS.²

The five most common cancers associated with LFS include:^1,2

• Adrenocortical carcinomas
• Breast cancer
• Brain tumours
• Osteosarcomas
• Soft-tissue sarcomas

However, additional cancers that have also been observed in LFS include:

• Leukemia
• Colorectal cancer
• Stomach cancer
• Lung cancer
• Melanoma (skin cancer)
• Pediatric head and neck cancers
• Pancreatic cancer
• Prostate cancer

Aside from genetic testing, diagnosing LFS is based on individuals who fit the following criteria: ²

• A first-degree relative (parent, sibling, or child) with a LFS-related cancer (e.g., sarcoma, breast cancer, brain tumours, and adrenocortical carcinoma) diagnosed before the age of 45
• A second-degree relative (grandparent, aunt, or uncle) with an LFS-related cancer diagnosed before the age of 45

Cancer screening guidelines

Due to the high risk of cancer in LFS, several studies and validated recommendations have been proposed. Regular cancer screening is crucial for early detection and intervention.^1,2

The Toronto protocol is an established guideline including specific tests and the frequency at which they should be conducted. Studies utilising this protocol showed that frequent screening and tests, including Magnetic Resonance Imaging (MRI) and brain MRI, had over 90% compliance rates. Of those that underwent frequent surveillance, most tumours were detected at an early stage, before malignant transformation. An increase in overall survival rates was also observed.^1,2

The Toronto Protocol is as follows:^1,2,3,4

• Abdominal and pelvic ultrasound every 3-4 months from birth to age 18, then every 6 months
• Whole body MRI annually from age 20 
• Breast examination every 6-12 months from age 20
• Breast MRI or mammogram annually from age 30
• Brain MRI annually 
• Upper endoscopy and colonoscopy every 2-5 years from age 25
• Dermatologic exam annually from age 18

Additionally, tests or screening recommendations include: 

• Adrenocortical carcinoma-specific blood tests
• Screening for cancers (eg, lung, pancreatic) based on family history or risks
• A bilateral mastectomy can be considered as a risk reduction strategy for those at high risk of breast cancer

Types of cancer screenings

Different methods of cancer screening are considered for various types of cancers. Examples of screening methods include:^1,5,6,7,8

• Imaging
  • Whole body MRI: This method creates detailed images of the full body
  • Brain MRI: This is used to detect any tumours in the brain, specifically
  • Ultrasound: This method creates images of internal organs and is particularly useful to detect, for example, adrenal tumours
• Breast cancer screening
  • Breast exam: This is a physical exam conducted to detect lumps or changes in the breast
  • Breast MRI or mammogram (X-ray): These methods create detailed images of the breast for early-stage detection. 
• Endoscopic exams
  • Upper endoscopy: This method uses a camera to examine the oesophagus and stomach
  • Colonoscopy: This method uses a camera to examine the rectum and the colon
• Dermatologic exams
  • Skin examination: This is a physical exam to check for abnormal moles or changes in the skin to detect aggressive skin cancers, such as melanoma, early

The importance of surveillance and screening has been shown through studies that highlight the benefit of intensive surveillance aimed at early tumour detection. These screenings identify tumours at the pre-malignant stage, which tend to be low grade and therefore more treatable. Additionally, people with LFS should avoid radiation and chemotherapy due to the risk of secondary malignancies, making early detection and intervention even more important.²

Challenges in screening

Some of the challenges that arise as a result of screening for cancers in LFS include access, psychological impact, and financial burden. Access to healthcare and screening resources limits the ability of several healthcare facilities to conduct individualised, repeated screening for these people. Additionally, the psychological impact of frequent screenings and the threats to their well-being can lead to anxiety and stress for both themselves and their families. The emotional burden and fear of potential cancer detection can also lead to fewer people participating in screening programs and fewer people adhering to the schedules. The cost of frequent imaging and examinations also poses a challenge to healthcare facilities and families, and can be straining for families or areas with limited resources.^1,2,9

It is therefore important to consider the balance between benefits and the burden of surveillance protocols in people with LFS. Efforts to reduce the psychological impact and personalise support to different individuals are essential to improve overall survival and quality of life.²

Role of genetic counselling

Genetic counselling is conducted by genetics professionals after an individual has been diagnosed with the condition. Counselling supports families and individuals in both understanding the risks of developing cancers and decision-making on screening protocols, prevention, and treatments. They are also involved in obtaining detailed family history and pedigrees to identify cancer patterns and risks. In addition, they provide means for genetic testing for TP53 mutants and interpret the test results of the variant. Importantly, education about the condition itself and emotional support for coping with the challenges of having a cancer syndrome are crucial and provided by genetic counsellors.^1,4

Summary

Li-Fraumeni Syndrome is a rare, autosomal dominant, inherited cancer syndrome that most commonly occurs as a result of a TP53 gene mutation. It leads to a high risk of cancer development and varies in types of cancer and age of onset. Cancers most commonly seen in Li-Fraumeni Syndrome include adrenocortical carcinomas, breast cancer, brain tumours, osteosarcomas, and soft-tissue sarcomas. The high risk of cancer led to several studies investigating the benefit of frequent screening and surveillance in these individuals. The Toronto protocol highlights several recommended imaging methods, including whole body MRIs and examinations, including breast examinations, to be conducted for early detection and intervention. Despite the value in this approach, access to healthcare, psychological impact, and financial burden pose significant challenges. The balance between benefit and burden, therefore, must be considered carefully. Genetic counsellors also support this process by guiding individuals through the decision-making process and providing emotional support.