C16.6
BillableMalignant neoplasm of greater curvature of stomach, unspecified
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C16.6 an HCC code?
Yes. C16.6 maps to Lung and Other Severe Cancers under the CMS-HCC V28 risk adjustment model (and Lung and Other Severe Cancers under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for C16.6
For C16.6 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically — it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed C16.6 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C16.6 is the ICD-10-CM diagnosis code for malignant neoplasm of greater curvature of stomach, unspecified. Cancer of the greater curvature of the stomach (the larger outer curve of the stomach) when the specific location is not further specified. C16.6 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of digestive organs (c15-c26).
Under the CMS-HCC V28 risk adjustment model, C16.6 maps to Lung and Other Severe Cancers (HCC 20) with a community, non-dual, aged base RAF weight of 0.000. Under the older V24 model, C16.6 mapped to the same category but with a base RAF weight of 0.973 — V28 recalibrated weights across the entire model. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
Use this code only when the greater curvature is documented but no more specific anatomical site is identified. Because C16.6 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for C16.6 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code only when the greater curvature is documented but no more specific anatomical site is identified
- •Consider requesting clarification on exact location if available, as it may impact staging and treatment
Clinical Significance
Cancer of the greater curvature of the stomach develops along the outer convex border of the stomach and may be associated with more advanced disease at presentation due to its anatomical relationship with the greater omentum and spleen. Greater curvature tumors can spread via the gastro-omental and splenic lymph node basins. Accurate coding of this specific location supports risk adjustment and reflects the distinct surgical considerations for this site.
Documentation Requirements
- ✓Documentation specifying greater curvature as the tumor location
- ✓Histological type and grade
- ✓Stage of disease including regional lymph node involvement
- ✓Relationship to adjacent structures (omentum, spleen)
- ✓Treatment status