Breast Cancer Diagnosis and Staging

Introduction to Diagnosis

The National Comprehensive Cancer Network (NCCN) guidelines recommend core biopsy of the breast mass to confirm invasive carcinoma and determine histological type and grade, hormone receptor status, HER2 status, and proliferation markers (Ki67) 1, 2
Pathological confirmation is required for definitive diagnosis and treatment planning, with core biopsy providing critical information for treatment decisions, including hormone receptor status, HER2 status, tumor grade, and proliferation markers 1, 2

Routine systemic staging is not indicated for early breast cancer in the absence of symptoms, but may be considered if signs and symptoms are present, including chest diagnostic CT, abdominal ± pelvic diagnostic CT or MRI, and bone scan (category 2B) 1, 3
PET scan may be considered for larger stage IIB tumors (T3N0 or T2N1) when conventional imaging results are equivocal or suspicious, or when there are signs or symptoms suggesting metastatic disease 1
PET scan is not recommended for stage I (T1, N0, M0) breast cancer due to limited spatial resolution, low risk of distant metastases, and high rate of false positives 4, 5
PET scan is generally not recommended routinely for stage IIA breast cancer, except for large T2 tumors (>3cm), due to a low detection rate of distant disease 4, 5
PET scan is recommended for stage IIB and higher breast cancer, as it can detect distant metastases in 9.8-15% of patients, replace conventional imaging, and is more cost-effective with lower radiation dose 4, 5
PET scan is recommended for stage III (including inflammatory breast cancer), as it can detect additional nodal metastases in 23% and distant metastases in 14% of patients, and is valuable for radiation therapy planning 4, 5

Biopsy of the breast mass is essential to confirm invasive carcinoma, with core biopsy providing critical information for treatment decisions, including hormone receptor status, HER2 status, tumor grade, and proliferation markers 1, 2
If neoadjuvant therapy is planned, core biopsy with placement of image-detectable marker(s) must be done to demarcate the tumor bed, and biopsy of suspicious axillary lymph nodes should be performed with clip placement if positive 1
For inflammatory breast cancer, skin punch biopsies (at least two) are strongly recommended to document dermal lymphovascular tumor emboli 2

The NCCN guidelines recommend considering systemic staging only if signs and symptoms are present, and that biopsy of metastatic lesions should be considered as receptor status can change in some cases compared to the primary tumor 1, 3
PET scans should be reported according to PERCIST or EORTC PET response criteria, and quantitative features (SUVmax, MATV/MTV, TLG) provide valuable prognostic information 5
For patients on immunotherapy, special reporting considerations apply 5
For localized bone pain or elevated alkaline phosphatase, bone scan is recommended 4, 6
For abnormal liver function tests, abdominal symptoms, or abnormal abdominal exam, abdominal imaging (US, CT, or MRI) is recommended 4, 6
For pulmonary symptoms, chest diagnostic CT is recommended 4
PET scanning is not cost-effective or clinically beneficial for routine surveillance in asymptomatic patients 7
PET can provide valuable information about disease extent in locally advanced disease, potentially altering treatment decisions 5
When used appropriately, PET can reduce unnecessary biopsies and procedures by clarifying equivocal findings from conventional imaging 5