About 2-3% of osteosarcomas, 9% of rhabdomyosarcomas, and 7-20% of patients with multiple primary tumours have p53 mutations.Although most cases of this syndrome have early onset of cancer, cases have also been reported later in life. Diagnosis
Li–Fraumeni syndrome is diagnosed if these three criteria are met:

The patient has been diagnosed with a sarcoma at a young age (below 45). A first-degree relative has been diagnosed with any cancer at a young age (below 45). Another first- or a second-degree relative has been diagnosed with any cancer at a young age (below 45) or with a sarcoma at any age.Other criteria have also been proposed:
A proband with any childhood cancer or sarcoma, brain tumor or adrenal cortical carcinoma diagnosed before age 45
A first- or second-degree relative with a typical LFS malignancy (sarcoma, leukaemia, or cancers of the breast, brain or adrenal cortex) regardless of age at diagnosis
A first- or second-degree relative with any cancer diagnosed before age 60A third criterion has been proposed:
Two first- or second-degree relatives with LFS-related malignancies at any age. Management
Genetic counseling and genetic testing are used to confirm that somebody has this gene mutation. Once such a person is identified, early and regular screenings for cancer are recommended for them as people with Li–Fraumeni are likely to develop another primary malignancy at a future time (57% within 30 years of diagnosis).
Chompret criteria
A 2015 revision of the traditional Chompret criteria for screening has been proposed - a proband who has:
A tumor belonging to LFS tumor spectrum (e.g., premenopausal breast cancer, soft tissue sarcoma, osteosarcoma, CNS tumor, adrenocortical carcinoma) before age 46 years, and at least one first- or second-degree relative with LFS tumor (except breast cancer if the proband has breast cancer) before age 56 years or with multiple tumors at any age
Multiple tumors (except multiple breast tumors), two of which belong to LFS spectrum with the initial cancer occurring before the age of 46 years
An adrenocortical carcinoma, choroid plexus tumor, or rhabdomyosarcoma of embryonal anaplastic subtype, at any age of onset, irrespective of family history
Breast cancer before age 31

Recommendations
Recommendations for individuals from families affected by the syndrome include:
Avoidance of radiation therapy to reduce risk of secondary radiation-induced malignancies
Children and adults undergo comprehensive annual physical examination
Women undergo age-specific breast cancer monitoring beginning at age 25 years
All patients consult a physician promptly for evaluation of lingering symptoms and illnesses

Suggestions
Adults should undergo routine screening for colorectal cancer beginning no later than age 25 years. Individuals should undergo organ-targeted surveillance based on the pattern of cancer observed in their families. Prophylactic mastectomy to reduce the risk of breast cancer is an option. Epidemiology
Li–Fraumeni syndrome (LFS) is rare; as of 2011, cases had been reported in more than 500 families. The syndrome was discovered using an epidemiological approach.