genoCDS

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genoCDS is a clinical reference tool for qualified healthcare professionals only. Content is derived from published guidelines and regulatory sources and may contain errors or outdated information. It is not a substitute for professional medical judgment, institutional protocols, or individual patient assessment. Always verify recommendations against current primary sources before making clinical decisions. Full disclaimer →

Colorectal Cancer · Rectal Adenocarcinoma

Stage Stage IIA

Tumor >4–5 cm, no nodal or distant metastasis (T2b, N0, M0). Resectable.

2 test recommendations across 1 clinical indication

At Diagnosis

Stage IIA (T3, N0, M0) rectal cancer. MSI/MMR required for Lynch syndrome evaluation. MSI-H may qualify for neoadjuvant pembrolizumab (watch-and-wait strategy).

Required 1 test

RequiredFDA Companion Dx

Microsatellite Instability / Mismatch Repair Status (MSI/MMR)

MSI/MMR

LOINC 81695-4

Testing for microsatellite instability (MSI) and/or mismatch repair (MMR) deficiency. Methods: PCR-based MSI testing, IHC for MMR proteins (MLH1, MSH2, MSH6, PMS2), or NGS-based MSI calculation. MSI-H (high instability) / dMMR (deficient MMR) is an FDA-approved pan-tumor biomarker for pembrolizumab and dostarlimab. MSI-H/dMMR is rare in NSCLC (<1%) but justifies routine testing given pan-tumor approval. IHC for MMR proteins can be performed on most tissue specimens.

Ordering Note

Required for all Stage II rectal cancer. MSI-H qualifies for neoadjuvant pembrolizumab; complete pathologic response rates >50% in MSI-H rectal cancer (NICHE-2). May spare surgery and radiation.

Specimen

FFPE tumor tissue (≥10% tumor)

Evidence

NCCN
NCCN CRC v4.2024
NCCN Cat. 1

Recommended 1 test

RecommendedFDA Companion Dx

BRAF V600E Mutation Analysis

BRAF V600E

LOINC 81527-9

Detection of BRAF V600E (p.Val600Glu) point mutation. Dabrafenib + trametinib (Tafinlar + Mekinist) is FDA-approved for BRAF V600E-mutant metastatic NSCLC. BRAF V600E occurs in 1.5–4% of NSCLC, more commonly in adenocarcinoma, and is enriched in current/former smokers. Non-V600E BRAF mutations occur more frequently but currently lack approved targeted therapy.

Ordering Note

Recommended when MSI-H detected. BRAF V600E distinguishes sporadic MSI from Lynch syndrome.

Specimen

FFPE tumor tissue (≥10% tumor)Liquid biopsy (ctDNA)

Evidence

NCCN
NCCN CRC v4.2024
NCCN Cat. 2A

Payer Coverage

Payer Coverage Summary

Coverage status as of last policy review. Prior authorization requirements and coverage criteria may change. Verify directly with each payer before ordering.

TestMedicare (CMS)UnitedHealthAnthem BCBSHumanaCignaAetna
MSI/MMRCoveredCoveredUnknownUnknownUnknownUnknown

Coverage data last verified via automated policy research. Always confirm current policies with each payer.

Reference only. Testing guidance shown is derived from published clinical guidelines and regulatory sources. It does not constitute a clinical recommendation for any individual patient. Payer coverage information is a general summary and may not reflect current policy or individual benefit design. Full disclaimer

Recommendations on this page are derived from publicly available guidelines (NCCN, ASCO, ESMO, FDA, OncoKB) and are paraphrased for reference. They do not constitute medical advice. Evidence levels reflect the grading systems of each respective organization and should be interpreted in clinical context. This reference is updated periodically but may not reflect the most recent guideline revisions.