[Colorectal Carcinoma with Suspected Lynch Syndrome: A Multidisciplinary Algorithm]

Area of Science:

• Oncology
• Genetics
• Hereditary Cancer Syndromes

Background:

• Lynch syndrome accounts for 3-5% of colorectal cancers and is a leading hereditary cause of endometrial cancer.
• It is associated with increased risks for gastric, ovarian, and urinary tract cancers.
• Clinical practice often involves underdiagnosis due to diagnostic uncertainties and lack of awareness.

Purpose of the Study:

• To review and discuss optimized strategies for improved detection of Lynch syndrome.
• To establish a clinical algorithm for diagnostic procedures and surgical options in colorectal cancer patients.
• To highlight the importance of informed decision-making for patients regarding prophylactic surgeries.

Main Methods:

• Ascertainment and evaluation of family history using Amsterdam-II and revised Bethesda criteria.
• Immunohistochemical staining for mismatch-repair genes and BRAF testing for MLH1 loss.
• Microsatellite instability testing, genetic counseling, and mutation analysis when indicated.

Main Results:

• Pathological identification of suspected Lynch syndrome is feasible and straightforward.
• Timely analysis of tumor biopsies is essential for offering extended or prophylactic surgeries.
• Underdiagnosis persists due to limitations in clinical practice, family history assessment, and awareness.

Conclusions:

• Optimized strategies involving family history, molecular testing, and genetic counseling can improve Lynch syndrome detection.
• Multidisciplinary cooperation between gastroenterologists, pathologists, and surgeons is crucial.
• Addressing underdiagnosis is vital to prevent metachronous cancers and ensure at-risk families benefit from screening.