Zachary Zumsteg, MD
Radiation Oncology · Sylmar, CANPI 1962729004
Payments from drug & device makers
What this record shows
Almost everything reported here is food and beverage — 100.0% of the total across 1 separate payments, which is the pattern of a clinician who attends manufacturer presentations rather than one with a consulting arrangement. Every reported general payment came from a single manufacturer, Coherus Oncology, Inc.. That places this record below the midpoint for radiation oncology clinicians in CA, where the typical reported total is $477.
Across 1 payment — averaging $142.01 each. Meals, travel, consulting and speaking fees, gifts and royalties reported by drug and device makers.
- Coherus Oncology, Inc.$142
Across 14 payments — averaging $11,007 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.
- Pfizer$154K
What the payments were for
- Food & beverage$142100%
Most of this is food and beverage — typically meals provided during product presentations at a clinic or hospital. Nationally that is the single largest category of reported payments by count.
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 |
|---|---|---|
| Coherus Oncology, Inc. | 1 | $142 |
How this compares
$142 in reported general payments places this provider in the 20th percentile of 627 radiation oncology providers in California.
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.
Other radiation oncology in Sylmar
- Rakesh PatelLos Gatos$1.3M
- Amir LavafPalm Springs$411K
- Albert ChangLos Angeles$290K
- Arya AminiDuarte$265K
- Rizwan NuraniApple Valley$220K
- Drew MoghanakiLos Angeles$183K
- Jyoti MayadevSan Diego$170K
- Percy LeeIrvine$125K
- Felix FengSan Francisco$99K
- Hyun KimDuarte$97K
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.