{"uid":"cap_xNT3P0YgFcRqhL4ZcnMIB","slug":"brain-metastasis-velocity-bmv-calculator-farris-2017-46ec6867","name":"Brain Metastasis Velocity (BMV) Calculator — Farris 2017","description":"Farris 2017 brain metastasis velocity: bmv = new_brain_metastases / years_since_first_srs, 1 decimal. new_brain_metastases integer 0-200; years_since_first_srs 0.01-30. Low if BMV <4 (median OS 12.4 months after initial distant brain failure), intermediate 4-13 (8.2), high >13 (4.3). Does not floor BMV (NRG-BN009). Not time since last SRS. magent does not count metastases on imaging. Not a diagnosis. Not a medical device.","url":"https://api.magentlab.com/api/calc/bmv","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET","HEAD","DELETE"],"type":"string"},"headers":{"type":"object","additionalProperties":{"type":"string"}},"queryParams":{"type":"object","required":["new_brain_metastases","years_since_first_srs"],"properties":{"new_brain_metastases":{"type":"integer","description":"Cumulative number of new brain metastases since first SRS (integer 0-200). Caller-assigned; magent does not count metastases on imaging."},"years_since_first_srs":{"type":"number","description":"Years since first SRS (0.01-30; must be > 0). Farris 2017 uses time since first SRS, not time since last SRS."}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.005","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.005/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_IR02nXEjX6l4K349ZYnYU","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.005","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Computes Brain Metastasis Velocity (BMV) per Farris 2017, stratifying patients into low/intermediate/high risk categories after initial SRS failure","exampleAgentPrompt":"Calculate the brain metastasis velocity for a patient who has had 8 new brain metastases in the 2.5 years since their first SRS — I need to know the BMV and whether that puts them in the low, intermediate, or high risk category per Farris 2017.","exampleUseCases":[{"title":"Post-SRS risk stratification for neuro-oncology","prompt":"My patient had their first SRS 3 years ago and has developed 15 new brain metastases since then — can you calculate their brain metastasis velocity and tell me their Farris 2017 risk category and expected median OS?"},{"title":"Clinical trial eligibility screening","prompt":"I need to screen a patient for NRG-BN009 criteria. They've had 5 new brain metastases over 1.2 years since first SRS — compute their BMV and tell me if it's low, intermediate, or high."},{"title":"Comparing two patients' BMV trajectories","prompt":"Can you calculate the Farris 2017 BMV for two patients? First patient: 3 new brain mets over 0.75 years since first SRS. Second patient: 20 new brain mets over 1.5 years since first SRS. Give me both risk categories."}],"resultDescription":"Returns the calculated BMV value (new_brain_metastases divided by years_since_first_SRS, rounded to 1 decimal place) along with the risk stratum: low (<4, median OS ~12.4 months after initial distant brain failure), intermediate (4–13, median OS ~8.2 months), or high (>13, median OS ~4.3 months). Does not floor BMV. Not a diagnosis or medical device output.","failureModes":["new_brain_metastases outside range 0–200 returns validation error","years_since_first_srs of 0 or negative returns error (must be >0.01)","years_since_first_srs above 30 may be rejected","missing required query parameters returns 400-level error","payment failure (x402) if USDC not provided"],"whenToPreferThis":"Use this endpoint when you need to apply the Farris 2017 Brain Metastasis Velocity formula specifically — particularly for NRG-BN009 protocol screening or post-SRS OS stratification. Prefer this over manual calculation when you need the exact BMV decimal and the low/intermediate/high risk band in a single call. Note: this endpoint does not count metastases from imaging — the caller must supply the count.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T07:07:36.210Z","isFirstParty":false}