C18.2
BillableMalignant neoplasm of ascending colon
HCC Category Mapping
V28HCC 22 — Colorectal, Bladder, and Other Cancers
0.000V24HCC 11 — Colorectal, Bladder, and Other Cancers
0.306ESRDHCC 11 — Colorectal, Bladder, and Other Cancers
0.000What This Code Means
Cancer that develops in the ascending colon, which is the first vertical section of the large intestine on the right side of the abdomen.
Coding Tips
- •Right-sided colon cancers may present with different symptoms than left-sided lesions; document clinical presentation
- •Verify histological type and stage; adenocarcinoma is the most common type
Clinical Significance
Malignant neoplasm of the ascending colon is classified as a right-sided colon cancer, which has distinct clinical and molecular characteristics compared to left-sided colon cancer. Right-sided cancers tend to present later with anemia and weight loss rather than obstruction or bleeding, and they are more commonly associated with microsatellite instability. These distinctions affect treatment decisions, including the potential benefit of immunotherapy for microsatellite instability-high tumors.
Documentation Requirements
- ✓Documentation confirming ascending colon as the tumor location
- ✓Histological type and grade
- ✓Stage of disease (TNM staging)
- ✓Microsatellite instability or mismatch repair status
- ✓Colonoscopy or surgical documentation confirming the site
Commonly Confused Codes
C18.0 — Cecum: the cecum is the blind pouch below the ileocecal valve; the ascending colon runs superiorly from the cecumC18.3 — Hepatic flexure: the hepatic flexure is the turn at the top of the ascending colon; ensure tumor is in the straight ascending portionC18.9 — Colon, unspecified: use C18.2 when ascending colon is specifically documented
Code Hierarchy
└C18Malignant neoplasm of colon└C18.2Malignant neoplasm of ascending colon
└C18.2Malignant neoplasm of ascending colon