C18.6 Malignant neoplasm of descending colon

The ICD-10-CM code for Malignant neoplasm of descending colon is C18.6 (FY2026). It is a billable, claim-ready diagnosis code.

Classification

Chapter

2: Neoplasms (C00-D49)

Section

C15-C26: Malignant neoplasms of digestive organs (C15-C26)

Category C18

11 codes (10 billable)

FY2026 Status

Stable since FY2024

U.S. Hospital Utilization

• An estimated 7,965 U.S. inpatient stays in 2023 included C18.6 among the documented diagnoses.
• 4,915 stays listed it as the principal diagnosis.

Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.

Official Coding Guidelines

Tx of primary site (TOC entry)

a. Admission/Encounter for treatment of primary site ............................................................. 33

Tx of secondary site (TOC entry)

b. Admission/Encounter for treatment of secondary site .......................................................... 33

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

• CMS — ICD-10-CM Official Code Set and Guidelines, FY2026
• CDC/NCHS — ICD-10-CM Files and Browser Tool
• AHRQ — HCUP National Inpatient Sample, Frequencies by Diagnosis Code (2016–2023)

Cite This Page

Reference C18.6 with the canonical source and edition:

C18.6 — Malignant neoplasm of descending colon. ICD-10 Coding Pro (ICD-10-CM FY2026). https://icd10codingpro.com/codes/C18.6

Canonical URL: https://icd10codingpro.com/codes/C18.6