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ICD-10 Guide
ICD-10 CodesC18.6

C18.6

Billable

Malignant neoplasm of descending colon

BILLABLE STATUSYes
IMPLEMENTATION DATEOctober 1, 2015
LAST UPDATED09/05/2025

Code Description

ICD-10 C18.6 is a billable code used to indicate a diagnosis of malignant neoplasm of descending colon.

Key Diagnostic Point:

C18.6 refers to a malignant neoplasm located in the descending colon, which is part of the large intestine. Colorectal cancer, including cancers of the descending colon, is a significant health concern and is often diagnosed through screening methods such as colonoscopy, fecal occult blood tests, and imaging studies. The disease can present with symptoms such as changes in bowel habits, rectal bleeding, abdominal pain, and unexplained weight loss. Staging of colorectal cancer is crucial for determining the extent of disease and treatment options, typically classified using the TNM system (Tumor, Node, Metastasis). The presence of microsatellite instability (MSI) can indicate a specific subtype of colorectal cancer that may respond differently to certain therapies. Surgical approaches for treating malignant neoplasms of the descending colon often involve resection of the affected segment, which may include partial colectomy or total colectomy, depending on the tumor's size and location. Adjuvant therapies, including chemotherapy and radiation, may also be indicated based on the stage of the cancer and the patient's overall health.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Variability in staging and treatment protocols
  • Need for precise documentation of tumor location and size
  • Differentiation from benign conditions
  • Potential for multiple co-existing conditions

Audit Risk Factors

  • Inadequate documentation of staging
  • Failure to specify the exact location of the tumor
  • Misclassification of tumor type
  • Inconsistent coding of co-existing conditions

Specialty Focus

Medical Specialties

Oncology

Documentation Requirements

Detailed pathology reports, treatment plans, and follow-up notes are essential.

Common Clinical Scenarios

Patients undergoing chemotherapy or radiation therapy for colorectal cancer.

Billing Considerations

Ensure accurate staging and treatment documentation to support coding.

Gastroenterology

Documentation Requirements

Endoscopy reports, biopsy results, and imaging studies are critical.

Common Clinical Scenarios

Patients presenting with symptoms of colorectal cancer or undergoing screening.

Billing Considerations

Document findings from colonoscopies and any interventions performed.

Coding Guidelines

Inclusion Criteria

Use C18.6 When
  • Follow the official ICD
  • CM coding guidelines, ensuring accurate documentation of the diagnosis, staging, and treatment
  • Include any relevant co
  • morbidities and complications

Exclusion Criteria

Do NOT use C18.6 When
  • Exclude codes for benign neoplasms or other unrelated conditions

Related ICD-10 Codes

Related CPT Codes

44140CPT Code

Colectomy, partial, with anastomosis

Clinical Scenario

Used when a patient undergoes surgical resection of the descending colon.

Documentation Requirements

Operative report detailing the procedure and findings.

Specialty Considerations

Oncology and Gastroenterology must ensure accurate coding of the procedure.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of malignant neoplasms, improving the accuracy of data collection and reimbursement processes. C18.6 provides a clear distinction for malignant neoplasms of the descending colon, enhancing clinical documentation and coding precision.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of malignant neoplasms, improving the accuracy of data collection and reimbursement processes. C18.6 provides a clear distinction for malignant neoplasms of the descending colon, enhancing clinical documentation and coding precision.

Reimbursement & Billing Impact

reimbursement processes. C18.6 provides a clear distinction for malignant neoplasms of the descending colon, enhancing clinical documentation and coding precision.

Resources

Clinical References

  • •
    American Cancer Society - Colorectal Cancer

Coding & Billing References

  • •
    American Cancer Society - Colorectal Cancer

Frequently Asked Questions

What is the significance of microsatellite instability in colorectal cancer?

Microsatellite instability (MSI) is a condition of genetic hypermutability that can affect the prognosis and treatment options for colorectal cancer. Tumors with MSI may respond better to certain immunotherapies, making it crucial for treatment planning.