Table 1.

Staging Algorithm Steps for Breast Cancer

Steps for stage identification	Codes
Step 1. All cases meeting newly diagnosed breast cancer criteria were examined for stage IV metastatic identification criteria Women with ≥2 claims coded for breast cancer metastasis, ≥15 days apart, occurring from 1 month before to 6 months after the index diagnosis date were designated as having stage IV disease The ICD-9 diagnosis code could be in any position on a claim	ICD-9 diagnosis codes for breast cancer metastasis: 196.0x–196.2x, 196.5x–196.9, 197.xx, 198.xx
Step 2. Cases not meeting stage IV metastatic criteria were examined for evidence of active treatment with breast cancer surgery (inpatient or outpatient) The breast cancer surgery claim was required to be within 9 months of the index diagnosis date and contain a breast surgery CPT code or ICD-9 procedure code in the primary position of the claim For women identified as having risk-reduction surgery, additional treatment indicating malignancy was required. Treatment for malignancy included radiation therapy, chemotherapy, and axillary node sampling	CPT codes for breast cancer surgery: 19120, 19125, 19126, 19301, 19302–19307 ICD-9 procedure codes for breast cancer surgery: 85.21–85.23, 85.41–85.48 Risk-reduction surgery: CPT codes 19303, 19304; CPT procedure codes 85.41, 85.42 Axillary node sampling: CPT codes 38500, 38505, 38525, 38740, 38745; ICD-9 procedure codes 40.23, 40.3, 40.51 [Codes for radiation therapy and chemotherapy are noted below]
Step 3. Women receiving neoadjuvant therapy and/or cases coded for axillary lymph node involvement were identified with stage III breast cancer Neoadjuvant therapy was indicated by ≥2 claims for radiation and/or chemotherapy after the index diagnosis date and before the breast surgery date Axillary lymph node involvement was indicated by ≥2 claims ≥15 days apart containing ICD-9 code 196.3 in any position of the claim, occurring within 6 months of the index diagnosis date	Radiation HCPCS codes: 77261–77263, 77280–77299, 77300–77370, 77371–77399, 77401–77417, 77418, 77421, 77422–77423, 77427–77499, 77520–77525, 77600–77620, 77750–77799 Radiation revenue code: 333 Chemotherapy J codes: J9000-J9999, J8510, J8520, J8521, J8530, J8560, J8561, J8565, J8600, J8610, J8700, J8705, J8999 Oral chemotherapy NDCs were obtained from Medi-Span 2013; available upon request ICD-9 diagnosis code for axillary lymph node involvement: 196.3
Step 4. Cases coded for in situ disease were identified with stage 0 breast cancer In situ disease was indicted by ≥2 claims ≥15 days apart containing ICD-9 diagnosis code 233.0, occurring within 6 months of the index diagnosis date	ICD-9 diagnosis code for in situ breast cancer: 233.0
Step 5: Remaining cases were designated as stage I/II disease

CPT indicates Current Procedural Terminology; HCPCS, Healthcare Common Procedure Coding System; ICD-9, International Classification of Diseases, Ninth Revision; NDC, National Drug Code.

Source: Milliman's study protocol.