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Li-Fraumeni Syndrome


Enviado por   •  28 de Septiembre de 2014  •  Ensayos  •  3.191 Palabras (13 Páginas)  •  180 Visitas

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Li-Fraumeni Syndrome

Synonym: SBLA Syndrome (Sarcoma, Breast, Leukemia, and Adrenal Gland)

Katherine Schneider, MPH, Kristin Zelley, MS, Kim E Nichols, MD, and Judy Garber, MD, MPH.

Author Information

Initial Posting: January 19, 1999; Last Update: April 11, 2013.

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Summary

Disease characteristics. Li-Fraumeni syndrome (LFS) is a cancer predisposition syndrome associated with the development of the following classic tumors: soft tissue sarcoma, osteosarcoma, pre-menopausal breast cancer, brain tumors, adrenocortical carcinoma (ACC), and leukemias. In addition, a variety of other neoplasms may occur. LFS-related cancers often occur in childhood or young adulthood and survivors have an increased risk for multiple primary cancers. Age-specific cancer risks have been calculated.

Diagnosis/testing. LFS is diagnosed in individuals meeting established clinical criteria or in those who have a germline mutation in TP53 regardless of family cancer history. At least 70% of individuals diagnosed clinically have an identifiable germline mutation in TP53, the only gene so far identified in which mutations are definitively associated with LFS.

Management. Treatment of manifestations: Routine oncologic management is recommended for malignancies in individuals with LFS, with the exception of breast cancer, in which mastectomy rather than lumpectomy is recommended in order to reduce the risks of a second primary breast tumor and avoid radiation therapy. Concerns about increased risk for radiation-induced second primary tumors has led to more cautious use of therapeutic radiation in general, but most experts recommend that treatment efficacy be prioritized above concerns about late effects after careful analysis of risks and benefits.

Prevention of primary manifestations: Prophylactic mastectomy to reduce the risk for breast cancer is an option for women with a germline TP53 mutation. Recent recommendations for colonoscopy may be considered surveillance as well as primary prevention of colorectal cancer.

Prevention of secondary complications: Avoidance of exposure to radiation therapy, when possible, to reduce the risk of secondary radiation-induced malignancies.

Surveillance: There are no definitive prospective data on the optimal methods for and efficacy of tumor surveillance for children or adults with a germline TP53 mutation. Currently, it is recommended that: (1) children and adults undergo comprehensive annual physical examination; (2) children and adults be encouraged see a physician promptly for evaluation of lingering symptoms and illnesses; (3) women undergo breast cancer monitoring, with annual breast MRI and twice annual clinical breast examination beginning at age 20-25 years. The use of mammograms has been controversial because of radiation exposure and limited sensitivity. When included, annual mammograms should alternate with breast MRI, with one modality every six months; (4) adults consider routine screening for colorectal cancer with colonoscopy every 2-3 years beginning no later than age 25 years; (5) individuals consider organ-targeted surveillance based on the pattern of cancer observed in their family. Intensified surveillance with whole-body MRI protocols for adults and children who carry a germline TP53 mutation are being evaluated in investigational settings.

Agents/circumstances to avoid: People with germline TP53 mutations should: (1) avoid known carcinogens including sun exposure, tobacco use, occupational exposures, and excessive alcohol use; and (2) minimize exposure to diagnostic and therapeutic radiation.

Evaluation of relatives at risk: It is appropriate to offer genetic counseling and testing to all relatives who are at risk of having a familial TP53 mutation.

Genetic counseling. LFS is inherited in an autosomal dominant manner. The proportion of individuals with a de novogermline TP53 mutation is estimated to be between 7% and 20%. Offspring of an affected individual have a 50% chance of inheriting the deleterious mutation. Predisposition testing for at-risk family members and prenatal testing for pregnancies at increased risk are possible if the heritable mutation in the family has been identified.

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Diagnosis

Clinical Diagnosis

Classic Li-Fraumeni syndrome (LFS) is defined by presence of all of the following criteria:

• A proband with a sarcoma diagnosed before age 45 years

• A first-degree relative with any cancer before age 45 years

• A first- or second-degree relative with any cancer before age 45 years or a sarcoma at any age [Li et al 1988]

The diagnosis of LFS should also be suspected in individuals with the following:

• Any individual who meets the Chompret criteria for TP53 testing. It is estimated that at least 20% of individuals who meet the Chompret criteria have a detectable TP53 mutation [Chompret et al 2001]. More recent series have shown that 92%-95% of individuals who tested positive for germline TP53 mutations met the revised Chompret criteria for LFS [Gonzalez et al 2009b, Tinat et al 2009, Ruijs et al 2010]:

o Proband with a tumor belonging to the LFS tumor spectrum (e.g. soft tissue sarcoma, osteosarcoma, brain tumor, pre-menopausal breast cancer, adrenocortical carcinoma, leukemia, lung bronchoalveolar cancer) before age 46 years AND at least one first- or second-degree relative with a LFS tumor (except breast cancer if the proband has breast cancer) before age 56 years or with multiple tumors; OR

o Proband with multiple tumors (except multiple breast tumors), two of which belong to the LFS tumor spectrum and the first of which occurred before age 46 years; OR

o Proband with adrenocortical carcinoma or choroid plexus tumor, regardless of family history

• Any woman who has a personal history of early-onset breast cancer and does not have an identifiableBRCA1 or BRCA2 mutation. A woman who is diagnosed with breast cancer before age 30 years and is not found to have a pathogenic BRCA mutation has an estimated 4%-8% likelihood of having a TP53 mutation [Gonzalez et al 2009b, Mouchawar et al 2010, McCuaig et al 2012]. Women with breast cancer diagnosed between ages 30 and 39 years may also have a small increased risk of having a TP53 mutation [Lee et al 2012].

o The likelihood of a TP53 mutation in

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