Summary & Overview
HCPCS G9100: Gastric Cancer Disease-Status Post R0 Resection
HCPCS Level II code G9100 identifies a disease-status classification for gastric cancer, specifically when adenocarcinoma is the predominant cell type and the patient is post R0 resection with no evidence of recurrence, progression, or metastases. Intended for use within a Medicare-approved demonstration project, the code captures a specific clinical state important for tracking outcomes, eligibility for follow-up interventions, and demonstration-based reimbursement reporting. Nationally, capturing clear disease-status codes supports quality measurement, research on survivorship, and programmatic evaluations tied to demonstration initiatives.
Key payers addressed in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The content outlines the clinical context of the code, typical sites of service, and common administrative elements associated with its use. Readers will learn the clinical scenario the code represents, how it is applied in outpatient oncology settings, and what to expect in terms of payer coverage environment and administrative modifiers where applicable. The publication also summarizes benchmarking and policy considerations relevant to demonstration projects and post-surgical surveillance coding.
Data not available in the input: Associated taxonomies, ICD-10 diagnoses, related codes, and service-line specifics beyond the description provided.
Billing Code Overview
HCPCS Level II code G9100 denotes oncology disease status for gastric cancer, limited to adenocarcinoma as the predominant cell type, for patients who are post R0 resection (with or without neoadjuvant therapy) and have no evidence of disease recurrence, progression, or metastases. This code is intended for use in a Medicare-approved demonstration project and identifies the disease-status classification rather than a specific treatment procedure.
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Service type: Disease status classification and clinical surveillance assessment related to gastric adenocarcinoma following curative-intent resection
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Typical site of service: Oncology clinic or outpatient specialty center where post-operative disease-status evaluations and surveillance are performed
Clinical & Coding Specifications
Clinical Context
A 62-year-old patient with a history of localized gastric adenocarcinoma undergoes neoadjuvant chemotherapy followed by a curative-intent gastrectomy achieving an R0 resection. Postoperatively the patient enters surveillance with the oncology team. During a scheduled clinic follow-up and tumor board review, the treating medical oncologist documents disease status as “no evidence of recurrence, progression, or metastases” after review of recent cross-sectional imaging (CT chest/abdomen/pelvis), endoscopic surveillance, and pathology reports. The clinical workflow for use of G9100 in a Medicare-approved demonstration project includes: physician or advanced practice clinician assessment of clinical status; review of operative and pathology reports confirming R0 resection and predominant adenocarcinoma histology; review of imaging and endoscopy reports demonstrating no evidence of disease; documentation of surveillance plan and timing; coding and submission of the G9100 HCPCS Level II code to indicate disease status in project reporting. Typical site of service is outpatient oncology clinic or hospital outpatient department where follow-up evaluations and surveillance imaging reviews occur.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | No modifier | Used when no special circumstances apply to the service billing with . |