Summary & Overview
HCPCS G9101: Gastric Adenocarcinoma Disease Status, Post R1/R2 Resection
HCPCS Level II code G9101 designates a disease-status classification for gastric cancer when adenocarcinoma is the predominant cell type in patients who are post R1 or R2 resection and exhibit no evidence of disease progression or metastases. The code is notable for its specific clinical scope and its intended use in Medicare-approved demonstration projects, making it relevant for oncology programs tracking post-surgical disease status and eligibility for demonstration-related reporting.
This analysis covers major national payers including Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the code's clinical definition and service context, along with what national payers typically consider when adjudicating similar oncology disease-status codes. The publication summarizes available benchmarks, coding and policy considerations relevant to demonstration projects, and the clinical context for post-resection surveillance in gastric adenocarcinoma.
The report is aimed at coding managers, oncology practice administrators, and policy analysts who require clear definitions, payer coverage context, and the implications of using a demonstration-project-specific HCPCS Level II code. Data not available in the input are identified where applicable.
Billing Code Overview
HCPCS Level II code G9101 describes an oncology disease-status classification for gastric cancer, limited to adenocarcinoma as the predominant cell type. The code applies to patients who are post R1 or R2 resection (with or without neoadjuvant therapy) and who have no evidence of disease progression or metastases, intended for use in a Medicare-approved demonstration project.
Service Type: Oncology — disease status assessment and classification
Typical Site of Service: Hospital outpatient oncology clinics, cancer centers, or specialty surgical follow-up clinics
Clinical & Coding Specifications
Clinical Context
A typical patient is a 62-year-old individual diagnosed with gastric adenocarcinoma who underwent surgical resection (R1 or R2 margin status) with or without neoadjuvant therapy and currently has no evidence of disease progression or distant metastases. The service represented by G9101 documents disease status evaluation for gastric cancer (adenocarcinoma predominant) in the context of a Medicare-approved demonstration project. Clinical workflow: the surgical oncologist or medical oncologist reviews operative and pathology reports confirming R1 (microscopically positive margin) or R2 (macroscopically positive margin) resection, and documents current disease status via history, physical examination, recent imaging review (CT abdomen/pelvis, PET/CT as available), tumor markers if used, and multidisciplinary tumor board discussion. The clinician records absence of radiographic progression or metastatic disease and certifies eligibility criteria for the demonstration project. Typical encounter locations include outpatient oncology clinic, hospital-based outpatient clinic, or ambulatory surgery/oncology centers when performed as part of a scheduled post-operative or surveillance visit. Relevant team members include surgical oncology, medical oncology, radiology, pathology, oncology nursing, and case management for demonstration project enrollment and reporting.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | No modifier information provided / default |