The short answer
A denial is an appealable decision, not a final answer. Request peer-to-peer review, file an expedited internal appeal, then external review — which is independent and binding on your insurer.
A prior authorization denial is an appealable decision, not the end. Get the denial and its specific reason in writing before doing anything else.
For Medicare Advantage, Medicaid and CHIP plans covered by the CMS prior authorization rule, standard decisions are due within 7 calendar days and expedited decisions within 72 hours, with a specific reason required for denials. Marketplace plans sold on the federal exchange are excluded from those timeframes.
You have 180 days to file an internal appeal. Plans must decide within 15 days for prior authorization, 30 days for services already received, and as fast as your condition requires — at least within 4 business days — for urgent cases.
Use the word "expedited" and say the delay jeopardizes your health. That switches the clock from weeks to days.
Choose how you want to understand this
The full explanation.
A Denial Is a Decision You Can Overturn
Most people treat an insurance denial as a verdict. It is closer to a first draft. Denials are often reversed on peer-to-peer review or internal appeal. And if those fail, there is an independent process whose decision your insurer must obey by law.
The problem is that the clock runs while you work out what to do. In cancer, that matters. Oncology professional bodies report that prior authorization routinely delays treatment and imaging. Clinicians widely report patients being harmed by the wait. So aim for speed and documentation, not eloquence.
Day 0: Get It in Writing
Call the number on your insurance card. Ask for:
- The denial in writing, with the specific reason and the exact policy or criteria cited.
- The reference number, the reviewer's name or credential, and the date.
- The deadline for filing an internal appeal, and the address or portal to use.
The CMS interoperability and prior authorization rule covers Medicare Advantage plans, state Medicaid and CHIP agencies, and Medicaid and CHIP managed care plans. Under it, those plans must give a specific reason for a denial. They must decide standard requests within 7 calendar days and expedited requests within 72 hours. Qualified health plans on the federally facilitated Marketplace are excluded from those timeframes, so check your own plan documents if that is your coverage. A vague "not medically necessary" with no criteria is worth pushing back on.
Start a log the same day. Record the date, the time, who you spoke to, the reference number, and what was said. This is the single most useful thing you will do.
Day 1–2: Peer-to-Peer
Call your oncologist's office. Ask them to request a peer-to-peer review. That is a direct call between your doctor and the insurer's physician reviewer. It is the fastest route, and it does not use up your formal appeal rights. Many denials end here.
At the same time, ask for a letter of medical necessity. It should name your diagnosis, stage and biomarkers. It should name the guideline the treatment follows. It should say what has already been tried. And it should spell out the clinical consequence of delay.
Day 2–5: Internal Appeal, Expedited
If peer-to-peer does not resolve it, file the internal appeal. You have 180 days from the denial. Include your name, claim and member numbers, a copy of the denial, the letter of medical necessity, relevant records, and your log.
Plans must decide within:
- 15 days for prior authorization (services not yet received)
- 30 days for services already received
- Urgent cases: as fast as your condition requires, and at least within 4 business days
Ask for the expedited pathway in writing. State that delay would seriously jeopardize your health. For active cancer treatment this is usually true, and saying it explicitly changes the timeline from weeks to days. You can pursue an expedited external review at the same time as an urgent internal appeal.
If the Internal Appeal Fails: External Review
This is the step most people never take. It is also the strongest one.
An independent organization reviews the denial with no financial interest in the outcome. That may be a state process, an accredited independent review organization, or the federal HHS-administered process. Your insurer is required by law to accept the decision.
- File within 4 months of the final internal denial.
- Standard reviews are decided within 45 days; expedited within 72 hours.
- Cost: nothing under the federal process, and no more than $25 under most others.
The contact details are on your final denial letter and your Explanation of Benefits. If you cannot find them, call HealthCare.gov at 1-800-318-2596 or your state Department of Insurance.
Different Coverage, Different Route
- Original Medicare and Medicare Advantage have their own multi-level appeal process. It includes expedited routes when treatment is at risk.
- Medicaid appeals go through your state agency. You usually have a right to a fair hearing.
- Self-funded employer plans are regulated federally rather than by the state. Ask HR which external review process applies.
Get Help — This Is Someone's Job
Ask your cancer center for its financial navigator, prior authorization specialist or patient advocate. Most programs have one, and they run these appeals routinely. Your state Consumer Assistance Program or Department of Insurance can also file on your behalf. Bring your log.
Everything above describes US insurance rules.
Sources
Words to know
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Common questions
What is a peer-to-peer review and how do I get one?
It is a direct phone call between your oncologist and a physician reviewer at the insurer. It is the fastest route to reversal and it does not consume your formal appeal rights. Call your oncologist's office and ask specifically: "Can you request a peer-to-peer on this denial, and can it be scheduled this week?" Practices usually have staff who do this daily. Ask for the outcome in writing either way.
How do I know if my appeal should be expedited?
If waiting the standard timeframe would seriously jeopardize your life, health, or ability to regain maximum function, you qualify. For active cancer treatment that is frequently the case. Say it in those words in writing, and ask your oncologist to submit a short letter stating the clinical consequence of delay. Expedited urgent internal appeals must be decided as quickly as your condition requires and at least within 4 business days; expedited external reviews within 72 hours.
What is external review and is it really binding?
It is a review by an independent organization with no financial stake in the outcome — either a state process, an accredited independent review organization, or the federal HHS-administered process. Your insurer is required by law to accept the decision. You generally have 4 months from the final internal denial to file. There is no charge under the federal process and a maximum of $25 under most others. This is the strongest tool most patients have and it is badly underused.
Should I start treatment while I appeal?
Discuss it with your oncologist rather than assuming either way. Sometimes the practice will begin treatment and hold billing, sometimes the manufacturer has a patient assistance or bridge program, and sometimes there is a covered alternative that is clinically reasonable in the interim. What you should not do is quietly wait. Tell your oncologist the moment you learn of a denial so they can weigh the clinical risk of delay.
Who can help me if I cannot do this myself?
Ask your cancer center for its financial navigator, financial counselor or patient advocate — most programs have one and this is exactly their job. Your state Department of Insurance and its Consumer Assistance Program can help you file. HealthCare.gov's helpline is 1-800-318-2596. If your coverage is through an employer, the HR benefits contact can sometimes escalate faster than you can. Bring your written log to whoever helps you.
Questions to ask your doctor
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Where to get help with this, by name
A hospital social worker or financial navigator is the best first call if you have one. If you do not, these organisations help at no cost to you.
- Patient Advocate Foundation — (800) 532-5274. Case managers take on insurance appeals, denials and medical debt with you. Free.
- TotalAssist (Patient Advocate Foundation's copay programme, merged with the PAN Foundation in 2026) — 866-512-3861. Help with medication copays, coinsurance and deductibles, insurance premiums, and office-visit and administration charges on the day of treatment, across nearly 150 conditions.
- CancerCare — 800-813-HOPE (4673). Oncology social workers, free counselling and support groups. Limited financial help with transport, home care, child care and lodging for people in active treatment who meet their income guidelines — funding is first-come, first-served, so call to ask what is open.
- Triage Cancer — 424-258-4628. Free legal and financial navigation: insurance, employment rights, disability.
- Blood Cancer United (formerly the Leukemia & Lymphoma Society) — (800) 955-4572. Information Specialists answer questions on treatment, insurance and financial problems.
- HealthCare.gov — 1-800-318-2596. For questions about the external review process — the independent review your insurer is required by law to accept.
Your state Department of Insurance regulates insurers and takes consumer complaints. On Medicare, your State Health Insurance Assistance Program (SHIP) gives free one-to-one counselling. If a specific drug is the problem, ask the manufacturer about its patient assistance programme.
Phone numbers checked 31 July 2026. Programmes and eligibility change — if a number has moved, please tell us.
Plain-language explanation of the published sources cited on this page. AI-assisted, source-checked, not clinician-reviewed.
Written by: Cancer ExplainedSources last checked: 2026-07-30 what this meansLast updated: 2026-08-18Next planned review: 2027-01-30
How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status — Source checked. This page was written with AI assistance and checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
High-risk topic — talk to your care team. This topic can involve urgent, individual medical decisions. This page is general education only: it cannot tell you whether your situation is an emergency or what you personally should do. Follow your oncology team's instructions and contact them for individual guidance.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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