Six percent of 316,950 annual US breast cancer diagnoses present as metastatic. Within that metastatic population, HR+/HER2- disease is nearly three-quarters of the pool this model has to size precisely.
The funnel starts wide and narrows fast. The American Cancer Society estimates 316,950 new invasive breast cancer diagnoses among US women in 2025. SEER data shows that six percent of breast cancer patients present with distant, Stage IV disease at diagnosis, a share that has crept up from 5.6 percent in 2010 to 6.0 percent in 2021 as detection and staging have improved. That narrows the annual de novo metastatic population to roughly 19,000 patients, before counting the separate and larger pool of patients who recur to metastatic disease after initial early-stage treatment. Within the metastatic population, regardless of how it is defined, HR+/HER2- disease dominates. It represents 73.9 percent of metastatic breast cancer cases, the highest share of any receptor subtype.
That subtype concentration is exactly what a patient flow model has to get right before any commercial forecast means anything. CDK4/6 inhibitor combination therapy is NCCN's first-line standard of care for HR+/HER2- metastatic disease, so eligibility for this drug class tracks the subtype-positive metastatic pool itself rather than narrowing much further, unlike biomarker-gated therapies where a testing gap shrinks the addressable population well below the diagnosed one. Our funnel models both the de novo Stage IV entry point and the separate recurrence pathway explicitly, since a forecast built only on de novo metastatic incidence understates the true annual addressable pool. Every conversion step carries its SEER or ACS source, live in the model, so your team can defend the number in the first forecast review rather than discover the gap in it.
US HR+/HER2- mBC funnel — from annual diagnosis to the treatment-eligible pool
| Funnel Stage | Population | Source |
|---|---|---|
| Annual new invasive breast cancer diagnoses (US) | 316,950 | ACS 2025 |
| De novo Stage IV (metastatic) at diagnosis | ~19,000 (6.0%) | SEER 2010–2021 trend analysis |
| HR+/HER2- share of metastatic population | 73.9% | Published metastatic-cohort subtype analysis |
| CDK4/6i-eligible (1L standard of care) | Majority of HR+/HER2- metastatic pool | NCCN Clinical Practice Guidelines, Breast Cancer |
Sources: American Cancer Society, Breast Cancer Facts & Figures 2024-2025; SEER 2010-2021 stage-at-diagnosis trend analysis (npj Breast Cancer 2025); published metastatic breast cancer subtype incidence-proportion analysis; NCCN Clinical Practice Guidelines in Oncology, Breast Cancer.
What this model answers
Every section answers a named commercial question your team is asking, scoped to your asset.
Delivers
- De novo Stage IV incidence (6.0% of 316,950 annual diagnoses)
- the separate recurrence-to-metastatic pathway
- why a de-novo-only forecast understates the true addressable pool
Delivers
- NCCN first-line standard-of-care status for the HR+/HER2- metastatic subtype
- the absence of a comparable testing-treatment gap
- where the funnel actually narrows instead
Delivers
- 8-sheet structure (Strategic Context, Inputs, Model, Projections, Sensitivity, References, Market Context, QC)
- 119 formulas, zero hardcoded cells
- SEER/ACS source citation per conversion step
Custom model delivered in 72 hours.
Commission This ModelWhat's inside
- Why the recurrence pathway, not de novo incidence alone, sets the true addressable pool
- Pressure-tested against the SEER stage-at-diagnosis trend before the rest of the model is built out
- 316,950 annual US invasive breast cancer diagnoses (ACS 2025)
- Demographic and geographic distribution
- De novo Stage IV incidence (6.0% of diagnoses, SEER)
- The separate recurrence-to-metastatic pathway and why it must be modelled independently
- 73.9% HR+/HER2- share of the metastatic population
- How subtype testing accuracy affects the eligible pool
- NCCN first-line standard-of-care status and what that means for eligibility breadth
- Where ECOG PS and comorbidity exclusions narrow the pool instead
- Which assumptions move the eligible pool most
- Scenario ranges across de novo and recurrence pathways
- Patient volume by horizon under conservative, base, and aggressive scenarios
- Revenue translation inputs
- The open questions your forecasting team must close before the model is finalised
- Structured for an internal forecast-review session
Included with every brief
How AXLRx builds this model
Prepared by MoatRx analysts.
Every AXLRx patient flow model is built on a five-layer funnel, Population, disease burden (E1), diagnosis and specialist capture (E2), treatment and biomarker eligibility (E3), market access (E4), then Year 1-3-5 projections across three scenarios. Delivered as a live Excel workbook, not a static table: 119 formulas across 8 sheets, zero hardcoded cells.
US HR+/HER2- mBC sources: American Cancer Society Breast Cancer Facts & Figures 2024-2025, SEER stage-at-diagnosis trend data, published metastatic subtype incidence-proportion analysis, and NCCN Clinical Practice Guidelines in Oncology.
- Annual US invasive breast cancer diagnosis estimate verified against ACS Breast Cancer Facts & Figures 2024-2025
- Stage IV (metastatic) share at diagnosis and its 2010-2021 trend verified against SEER-based analysis (npj Breast Cancer 2025)
- HR+/HER2- share of the metastatic population verified against a published metastatic-cohort subtype incidence-proportion analysis
- CDK4/6i first-line standard-of-care status verified against NCCN Clinical Practice Guidelines in Oncology, Breast Cancer
Frequently asked questions
Commission this model
AXLRx delivers oncology patient flow models built for forecasting and launch teams sizing the US HR+/HER2- mBC opportunity. Custom model in 72 hours.
Specify your indication, market, and cohort definition.
AXLRx analyst confirms funnel scope and comparator set before building.
Research-verified patient flow model in 72 hours with optional analyst readout.