Gregory Gan, MD
Radiation Oncology · Kansas City, KSNPI 1568698561
Payments from drug & device makers
What this record shows
This record is dominated by consulting fees: $3,800 of the $4,579 with a category attached, or 83.0%. AstraZeneca accounts for 89.1% of it on its own, with 7 other manufacturers making up the rest. Reporting peaked in 2021 at $3,800 and has fallen 98.5% since, to $57 in 2025.
Across 12 payments — averaging $381.62 each. Meals, travel, consulting and speaking fees, gifts and royalties reported by drug and device makers.
- AstraZeneca$4K
- IBA Proton Therapy, Inc.$169
- Regeneron Healthcare Solutions, Inc.$122
- GT Medical Technologies, Inc$57
- Isoray, Inc$55
- EMD Serono, Inc.$41
- plus $55 from 2 others
Across 1 payment — averaging $166,353 each. Payments tied to a research study. These frequently flow through the physician to a hospital or research institution rather than to the physician personally.
- Siemens Medical Solutions USA, Inc.$166K
What the payments were for
- Consulting fees$3,80083%
- Food & beverage$77917%
General payments by program year
Who reported the general payments
Companies are grouped under their corporate parent — a single manufacturer often files under several CMS reporting entities. Research and ownership payments are counted separately and are not in this table.
| Company | Payments | Total |
|---|---|---|
| AstraZeneca | 4 | $4,081 |
| IBA Proton Therapy, Inc. | 1 | $169 |
| Regeneron Healthcare Solutions, Inc. | 1 | $122 |
| GT Medical Technologies, Inc | 1 | $57 |
| Isoray, Inc | 2 | $55 |
| EMD Serono, Inc. | 1 | $41 |
| Genentech, Inc. | 1 | $33 |
| Accuray Incorporated | 1 | $22 |
What the payments were tied to
Products named in the reported payments. Only payments of $100 or more are attributed here — the typical reported payment nationally is a meal worth about $16, and listing those product-by-product would be noise.
How this compares
$4,579 in reported general payments places this provider in the 85th percentile of 54 radiation oncology providers in Kansas.
Medicare billing
What this is not: this is the amount Original Medicare Part B allowed for services this provider billed in 2024. It is not their income. It excludes Medicare Advantage — now more than half of all Medicare enrollment — along with Medicaid and all commercial insurance, and it is gross practice revenue before staff, rent, supplies and malpractice premiums. CMS also suppresses any figure covering ten or fewer patients, so low-volume providers appear smaller than they are.
Most prescribed under Part D
| Drug | Claims | Cost to plans & patients |
|---|---|---|
| Gabapentin | 27 | $893 |
| Oxycodone Hcl | 29 | $623 |
| Lidocaine Hcl ViscousLidocaine Hcl | 19 | $141 |
| Methylprednisolone | 12 | $59 |
Paid to pharmacies, not to this prescriber.
Other radiation oncology in Kansas City
- Ronald ChenKansas City$31K
- Xinglei ShenKansas City$16K
- David AkhavanKansas City$9K
- Fen WangKansas City$7K
- Ronny RotondoKansas City$4K
- Jay ShiaoKansas City$3K
- Parvesh KumarKansas City$3K
- Ryan MorseKansas City$939
- Christopher LominskaKansas City$466
- Ramesh GadamKansas City$266
Where these figures come from
- Payments: CMS Open Payments, program years 2019–2025 (publication P06302026_06032026).
- Billing: Medicare Physician & Other Practitioners, data year 2024. Original Medicare Part B only.
- Identity: NPPES NPI Registry, July 2026.