Medigap Cancer Treatment Coverage 2026: Out-of-Pocket Costs for Chemotherapy, Radiation, and Immunotherapy by Plan
Medigap Cancer Treatment Coverage 2026: Out-of-Pocket Costs for Chemotherapy, Radiation, and Immunotherapy by Plan
TL;DR Quick Answer
Medigap Plan G covers 100% of Medicare-approved cancer treatment costs after the $257 annual Part B deductible — including chemotherapy, radiation, immunotherapy, and cancer surgery. Plan F covers everything with zero out-of-pocket. Plan N adds $20 copays for doctor visits (common during cancer treatment). High-Deductible Plan G requires meeting a $2,800 deductible first. For a typical cancer treatment regimen costing $150,000+ over a year, Plan G saves you $30,000+ compared to having Original Medicare alone.
Key Takeaways
- Plan G is the best Medigap plan for cancer patients — it covers the 20% Part B coinsurance on chemotherapy, radiation, and immunotherapy, which can easily exceed $30,000 per year
- Cancer treatment involves both Part A (hospital) and Part B (outpatient) costs — Part B covers most chemotherapy and radiation, meaning the 20% coinsurance is your biggest exposure without Medigap
- Immunotherapy drugs like Keytruda ($150,000+/year) are covered under Part B — without Medigap, your 20% share would be $30,000+ annually
- Oral chemotherapy pills fall under Medicare Part D, not Part B — Medigap does not cover these, but the 2026 $2,000 Part D out-of-pocket cap provides protection
- Plan N’s $20 doctor copays add up quickly during active cancer treatment with frequent oncologist visits, potentially costing $500-$1,000+ per year in copays alone
- You cannot switch Medigap plans after a cancer diagnosis without underwriting risk — making your initial plan choice critical
How Medicare Splits Cancer Treatment Costs: Part A vs Part B
Cancer treatment generates bills across multiple Medicare categories. Understanding this split is essential for knowing what your Medigap plan covers.
Medicare Part A Covers (Inpatient/Hospital):
- Inpatient chemotherapy administration (hospital admission required)
- Cancer surgery (inpatient setting)
- Inpatient radiation therapy
- Hospital stays for treatment complications
- Skilled Nursing Facility rehab after cancer surgery (days 21-100 coinsurance)
Medicare Part B Covers (Outpatient/Doctor):
- Outpatient chemotherapy infusion (the largest cost category for most patients)
- Radiation therapy (external beam, IMRT, proton therapy)
- Immunotherapy infusions (Keytruda, Opdivo, Herceptin, etc.)
- Oncologist office visits and consultations
- Diagnostic imaging (CT, PET, MRI scans)
- Lab work and blood tests
- Radiation oncology consultations
- Outpatient cancer surgery
The Part B 20% Problem
Original Medicare covers 80% of Part B costs. You pay the remaining 20% with no cap on out-of-pocket expenses. For cancer treatment, this 20% can be financially devastating:
| Cancer Treatment Type | Typical Annual Cost | Your 20% Share (No Medigap) |
|---|---|---|
| Chemotherapy (IV, common regimens) | $50,000 - $100,000 | $10,000 - $20,000 |
| Immunotherapy (Keytruda, annually) | $150,000 - $200,000 | $30,000 - $40,000 |
| Radiation therapy (full course) | $10,000 - $50,000 | $2,000 - $10,000 |
| Targeted therapy (oral + IV) | $100,000 - $300,000 | $20,000 - $60,000 |
| Cancer surgery (single procedure) | $15,000 - $50,000 | $3,000 - $10,000 |
This is why Medigap coverage is particularly critical for cancer patients — it eliminates or significantly reduces that 20% coinsurance.
Chemotherapy Out-of-Pocket Costs by Medigap Plan
Chemotherapy is primarily administered in outpatient settings (doctor’s office or infusion center), which means it falls under Medicare Part B. Here’s what each Medigap plan covers:
Cost Comparison: $75,000 Chemotherapy Regimen
| Medigap Plan | Part B Deductible | Coinsurance (20%) | Copays | Total Out-of-Pocket |
|---|---|---|---|---|
| Plan F | $0 (covered) | $0 (covered) | $0 | $0 |
| Plan G | $257/year | $0 (covered) | $0 | $257 |
| Plan N | $257/year | $0 (covered) | ~$500-$800 (oncologist visits) | $757 - $1,057 |
| HD Plan G | $257 + $2,800 HD | $0 after deductible | $0 | $3,057 |
| Original Medicare only | $257/year | $15,000 (20%) | $0 | $15,257 |
Note: Plan N’s copays apply to doctor office visits ($20 per visit). During active chemotherapy, you may see your oncologist weekly or biweekly — 25-40 visits per year is common.
Chemotherapy Drugs Covered Under Part B
Common Part B chemotherapy drugs (administered by a healthcare professional) include:
- Taxol/Taxotere (paclitaxel/docetaxel) — breast, lung, ovarian cancer
- Carboplatin/Cisplatin — various solid tumors
- 5-FU (fluorouracil) — colorectal, breast, head/neck cancer
- R-CHOP regimen — non-Hodgkin lymphoma
- Vincristine/Adriamycin — various cancers
All of these are covered at 80% by Part B, with Medigap covering the remaining 20%.
Radiation Therapy Costs by Medigap Plan
Radiation therapy is covered under Medicare Part B when delivered in an outpatient setting.
Typical Radiation Costs
| Radiation Type | Typical Full-Course Cost | Plan G Pays (after deductible) | Plan N Pays |
|---|---|---|---|
| External Beam Radiation | $10,000 - $25,000 | 100% of 20% coinsurance | 100% of coinsurance + $20/visit copays |
| IMRT (Intensity Modulated) | $15,000 - $40,000 | Full 20% coinsurance | Full coinsurance + copays |
| Proton Beam Therapy | $50,000 - $120,000 | Full 20% coinsurance | Full coinsurance + copays |
| Brachytherapy | $15,000 - $35,000 | Full 20% coinsurance | Full coinsurance + copays |
For a standard 6-7 week radiation course with daily treatments (30-35 sessions), Plan N patients should budget approximately $600-$700 in daily setup copays alone, since each treatment session may trigger the $20 office visit copay depending on how it’s billed.
Immunotherapy and Targeted Therapy Costs
Immunotherapy has revolutionized cancer treatment but comes with extraordinary costs. Most infused immunotherapies are covered under Medicare Part B.
Most Common Immunotherapy Drugs (Part B Covered)
| Drug | Cancer Type | Annual Cost | 20% Without Medigap |
|---|---|---|---|
| Keytruda (pembrolizumab) | Melanoma, lung, bladder, others | $150,000 - $200,000 | $30,000 - $40,000 |
| Opdivo (nivolumab) | Lung, kidney, melanoma | $120,000 - $180,000 | $24,000 - $36,000 |
| Herceptin (trastuzumab) | HER2+ breast cancer | $70,000 - $100,000 | $14,000 - $20,000 |
| Yervoy (ipilimumab) | Melanoma | $100,000 - $150,000 | $20,000 - $30,000 |
| Perjeta (pertuzumab) | HER2+ breast cancer | $80,000 - $120,000 | $16,000 - $24,000 |
| Darzalex (daratumumab) | Multiple myeloma | $100,000 - $150,000 | $20,000 - $30,000 |
With Plan G, your total out-of-pocket for any of these therapies is just the $257 annual Part B deductible. This is why Plan G is frequently recommended for beneficiaries concerned about future cancer risk.
Oral Cancer Drugs and Part D
Oral chemotherapy drugs (Xalkori, Tagrisso, Ibrance, etc.) are covered under Medicare Part D, not Part B. Medigap does not cover Part D costs. However, the 2026 Part D $2,000 annual out-of-pocket cap limits your exposure.
This means a cancer patient on both IV immunotherapy (Part B) and oral targeted therapy (Part D) would face:
- With Plan G: $257 (Part B deductible) + up to $2,000 (Part D cap) = $2,257 maximum
- Without Medigap: $30,000+ (Part B coinsurance) + up to $2,000 (Part D cap) = $32,000+
Cancer Surgery Costs by Medigap Plan
Cancer surgery involves both Part A (hospital/facility) and Part B (surgeon/anesthesia) components. For a detailed breakdown of surgery costs across all Medigap plans, see our Medigap Surgery Costs by Plan guide.
Quick Surgery Cost Reference
| Procedure | Typical Total Cost | Plan G Out-of-Pocket | Plan N Out-of-Pocket |
|---|---|---|---|
| Mastectomy | $15,000 - $30,000 | $257 (Part B deductible only) | $257 + ~$100-200 in copays |
| Lumpectomy | $8,000 - $15,000 | $257 | $257 + ~$80-120 in copays |
| Colectomy | $20,000 - $40,000 | $257 | $257 + ~$120-200 in copays |
| Prostatectomy | $15,000 - $35,000 | $257 | $257 + ~$100-180 in copays |
| Lung resection | $25,000 - $50,000 | $257 | $257 + ~$140-240 in copays |
Plan G covers the Part A deductible ($1,676 per benefit period) and all Part B coinsurance. For more on how different health profiles affect plan choice, see our Best Medigap Plans by Health Profile guide.
Clinical Trial Costs and Medigap Coverage
Medicare covers routine costs in qualifying cancer clinical trials under both Part A and Part B:
- Part A covers inpatient hospital costs during a clinical trial
- Part B covers doctor visits, tests, and outpatient procedures
- The research sponsor typically covers the cost of the experimental drug itself
Your Medigap plan applies exactly the same way it does for standard treatment — Plan G covers the 20% Part B coinsurance for clinical trial visits, and the Part A deductible is covered.
Total Annual Cancer Treatment Cost Comparison by Plan
For a patient receiving a full year of treatment (chemotherapy + radiation + surgery + immunotherapy):
| Scenario (Annual) | Original Medicare Only | Plan F | Plan G | Plan N | HD Plan G |
|---|---|---|---|---|---|
| Chemo ($75,000) | $15,257 | $0 | $257 | ~$1,000 | $3,057 |
| Radiation ($30,000) | $6,257 | $0 | included | ~$700 copays | included |
| Immunotherapy ($150,000) | $30,257 | $0 | included | ~$500 copays | included |
| Surgery ($30,000) | $7,933 | $0 | included | ~$160 copays | included |
| SNF Rehab (20 days) | $0 | $0 | included | included | included |
| TOTAL | ~$59,704 | $0 | $257 | ~$2,360 | $3,057 |
These figures assume all costs fall within a single benefit period and calendar year. Actual costs vary by treatment protocol, provider, and region.
Strategies to Minimize Cancer Treatment Costs with Medigap
1. Lock In Plan G During Open Enrollment
The single most important strategy is enrolling in Plan G during your 6-month Medigap Open Enrollment Period (starting the month you turn 65 and enrolled in Part B). During this window, you get coverage with no medical underwriting — meaning a future cancer diagnosis won’t lock you out. Learn more in our Open Enrollment Deadline Checker guide.
2. Understand Pre-Existing Condition Waiting Periods
If you enroll outside your open enrollment period, Medigap plans may impose a pre-existing condition waiting period of up to 6 months. Cancer would almost certainly trigger this. See our Pre-Existing Condition Waiting Period guide for details.
3. Consider Plan N’s Copay Math During Active Treatment
If you already have Plan N and receive a cancer diagnosis, calculate whether the copay costs justify switching. During active treatment with weekly oncologist visits, Plan N copays can total $500-$1,000+ annually. Compare this against Plan G’s higher premium to determine break-even. Our Plan N vs Plan G Total Cost Comparison can help with this analysis.
4. Don’t Drop Medigap for Medicare Advantage After a Diagnosis
If you have Medigap and receive a cancer diagnosis, do not switch to Medicare Advantage. Medigap’s guaranteed renewable coverage with no networks is a major advantage during complex cancer care. For a detailed comparison, see Medigap vs Medicare Advantage for Cancer Patients.
5. Stack Hospital Indemnity Insurance for Additional Protection
Some cancer patients add hospital indemnity insurance on top of Medigap to cover deductibles and non-medical costs (travel, lodging for treatment). Learn more in our Hospital Indemnity Stack guide.
6. Review Part D Coverage for Oral Cancer Drugs
Since Medigap doesn’t cover oral chemotherapy, make sure your Part D plan covers your prescribed oral cancer drugs on its formulary. The $2,000 annual out-of-pocket cap helps, but only if your specific drug is covered. See our Part D $2,000 Cap Strategy guide.
When to Switch Plans After a Cancer Diagnosis
Switching Medigap plans after a cancer diagnosis is extremely difficult because:
- Medical underwriting is required (in most states) — cancer history will likely result in denial or high rates
- Guaranteed issue rights are limited — cancer diagnosis alone doesn’t trigger guaranteed issue
- Birthday rules vary by state — only some states allow plan switching without underwriting
If you’re in a state with a birthday rule or other special protections, you may have options. Check our Birthday Rule by State guide and Switching Rules Checklist for details.
For beneficiaries considering switching from Medicare Advantage to Medigap after a diagnosis, understand the risks in our Medicare Advantage to Medigap Switching Cost Guide.
Frequently Asked Questions
Does Medigap Plan G cover chemotherapy treatments?
Yes, Medigap Plan G covers 100% of the 20% Part B coinsurance for outpatient chemotherapy after the $257 annual Part B deductible. For a typical chemotherapy regimen costing $75,000, your only out-of-pocket cost with Plan G is $257 per year. Chemotherapy administered during an inpatient hospital stay is covered under Part A, with Plan G covering the $1,676 Part A deductible.
How much does immunotherapy cost with Medigap Plan G?
With Medigap Plan G, immunotherapy drugs like Keytruda ($150,000-$200,000/year) cost you only the $257 annual Part B deductible. Without Medigap, your 20% coinsurance for Keytruda alone would be $30,000-$40,000 per year. Plan G covers the entire 20% Part B coinsurance amount for all Medicare-covered immunotherapy infusions.
Does Medigap cover oral chemotherapy pills?
No, Medigap does not cover oral chemotherapy pills. Oral cancer drugs fall under Medicare Part D prescription drug coverage. However, the 2026 Part D redesign caps your annual out-of-pocket spending at $2,000. Medigap only covers Part A and Part B costs — it does not supplement Part D. If you’re prescribed both IV and oral cancer drugs, your total maximum exposure with Plan G would be $257 (Part B deductible) plus up to $2,000 (Part D cap).
Can I switch Medigap plans after being diagnosed with cancer?
Switching Medigap plans after a cancer diagnosis is very difficult. In most states, you must pass medical underwriting, and active cancer or recent cancer history will typically result in denial. Some states have birthday rules or other protections that allow switching without underwriting. If you currently have Plan N and want Plan G, check your state’s birthday rule protections in our Birthday Rule by State guide.
Is Plan F or Plan G better for cancer treatment coverage?
Plan F is slightly better since it covers the $257 Part B deductible (making your out-of-pocket $0), but Plan F is not available to anyone who became Medicare-eligible after January 1, 2020. If you’re eligible for Plan F, it offers the most comprehensive cancer coverage with zero out-of-pocket costs. If you’re not eligible, Plan G is the next best option — the $257 annual deductible is minimal compared to the $30,000+ in coinsurance it covers. See our Plan F vs Plan G comparison for more details.
How do cancer clinical trial costs work with Medigap?
Medicare covers routine clinical trial costs (doctor visits, tests, standard procedures) under Part A and Part B, just like regular treatment. Medigap applies the same way — Plan G covers the 20% Part B coinsurance for trial-related visits and procedures. The experimental drug itself is typically paid by the trial sponsor at no cost to you. This means clinical trial participation with Plan G costs you no more than standard treatment.
What happens to my Medigap coverage if I need cancer surgery and chemotherapy in the same year?
Your Medigap coverage continues seamlessly across all treatment types. Plan G covers the Part A deductible for inpatient surgery ($1,676), the Part B deductible ($257), and all Part B coinsurance for outpatient chemotherapy and follow-up care. There’s no treatment cap or annual limit on Medigap coverage — it pays for all Medicare-approved costs regardless of how many different treatments you need in a year.
Will my Medigap premium increase if I get cancer?
No, Medigap premiums cannot be increased individually based on a cancer diagnosis. Premiums are set based on your age, location, tobacco use, and the plan type at the time of enrollment. However, insurance companies can request rate increases for an entire policy class (all policyholders in a plan/area), which affects everyone. See our Medigap Rate Increase Survival Guide for strategies to manage premium increases.
Don’t Leave Your Cancer Coverage to Chance
If you or a loved one is approaching Medicare eligibility, the Medigap plan you choose today determines your financial protection if cancer ever strikes. Plan G offers the strongest cancer treatment coverage available to new Medicare beneficiaries — covering 100% of Part B coinsurance after a modest $257 annual deductible.
Use our Medigap Plan Cost Estimator to compare total costs, or read our guide to choosing a Medicare Supplement insurance company to find the right carrier. For a broader overview of how Medigap handles chronic conditions, see our Chronic Condition Coverage Guide.
Have questions about your specific situation? Bookmark this page and share it with your family as you make your Medicare decisions. The right Medigap plan can literally save you $30,000+ per year during cancer treatment.