NPI registry status
Active
2026 NPPES data Medical Oncology Physician NPI 1871673350 MD
Verify on CMS → Cy Stein, MD
Medical Oncology Physician in Duarte, California.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 3,815 in Medical Oncology Physician, and covers specialty classification, practice address, and Medicare Part D prescribing data when reported. According to CMS, every field reflects the provider's official federal registration, see our methodology.
Federal data, no proprietary rating.
We show these CMS records as-is - no composite score, no star rating, no editorial opinion layered on top.
Prescribing volume
77
Medicare Part D claims · Medical Oncology Physician avg: 689
Compiled from official public sources by the PlainDoctor editorial team.
What the federal data shows
Cy Stein, MD filed 77 Medicare Part D claims in 2023 as a Medical Oncology Physician in Duarte, California.
- 77
- Part D claims, 2023
Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) - no proprietary rating or editorial opinion is applied.
Cy Stein, MD's Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
77 0th percentile higher than 0% of 1,370,886 prescribers
Each bar is a band; taller bars hold more prescribers. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source CMS Medicare Part D Prescriber Public Use File · 2023
◑
Board-eligible specialty (heuristic, not verified)
Cy Stein, MD practices in an ABMS-board-eligible specialty but we don't have enough CMS-participation signals to confirm active board-certified status. Consult CertificationMatters.org (the official ABMS public lookup).
What does the federal data show about Cy Stein, MD?
Quality data not reportedPrimary specialty
Medical Oncology Physician
Medicare Part D claims
77 89% vs specialty avg
Specialty distribution in California
How Medical Oncology Physician compares to other specialties among California providers
Board certification
Not published by CMS
CMS does not publish a per-provider board-certification field in NPPES. PlainDoctor does not have a reliable per-specialty certification rate to show for Medical Oncology Physician. Verify directly:
How MIPS and board certification work
The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.
Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).
Cy Stein, MD appears in the CMS NPPES registry as a Medical Oncology Physician provider holding MD credentials at 1500 DUARTE RD, Duarte, CA, 91010, with a listed phone of (626) 471-3890. NPI 1871673350 was issued on 10/17/2006.
Medicare Part D records for calendar year 2023 show 77 prescription claims written by this provider, covering N/A Medicare beneficiaries and totaling roughly $14K in drug spend.
Medical Oncology Physician is a narrow specialty nationwide, with 3,815 enrolled providers across 53 states and an average of 689 Part D claims per prescriber, so the context for interpreting these metrics differs meaningfully from a primary-care baseline.
Important: PlainDoctor is a directory of publicly available government data, not medical advice, a malpractice database, or a quality rating. Inclusion here does not imply a recommendation, and absence of complaints or sanctions on this page does not mean none exist, always verify credentials through the NPPES NPI Registry, your state medical board, and the ABMS or AOA before making healthcare decisions.
Practice Address
Provider Details
| NPI | 1871673350 |
|---|---|
| Specialty | Medical Oncology Physician |
| Credentials | MD |
| Gender | Male |
| NPI Issued | 10/17/2006 |
License & disciplinary context - California MBC 2023 annual report
Aggregate state board data only, NOT a determination of any individual provider's status. The figures below describe statewide disciplinary activity across all ~150K California medical licensees in 2023 - they are NOT specific to Cy Stein, MD. To verify Cy Stein, MD's current license status, search the MBC public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.
576
Total board actions, California 2023
Across 556 cases
3.84
Actions per 1,000 licensees
California statewide rate
probation
Most common action type
186 cases
MBC publishes annual disciplinary statistics as part of public-record reporting under each state's Administrative Procedure Act. See the full breakdown by action type and year on the California disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.
Medicare Part D Prescribing Data
CMS Medicare Part D prescriber-level data for calendar year 2023.
77
Total Claims
$14K
Total Drug Cost
N/A
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 192
- Total Day Supply
- 5,645
- Generic Drug Cost
- $1K
Patient Demographics
- Average Patient Age
- 70.0 years
- Avg HCC Risk Score
- 1.39
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
| Drug | Claims |
|---|---|
| Methotrexate Methotrexate Sodium | 12 |
| Duloxetine Hcl | 11 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Medical Oncology Physician Overview
How Cy Stein, MD fits within the Medical Oncology Physician landscape nationally.
3,815
Medical Oncology Physician Providers in US
53
States with Medical Oncology Physician
689
Avg Claims per Provider
Cy Stein, MD's 77 claims are below the specialty average of 689.
Nearby Medical Oncology Physician Providers in California
Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as Stein.
Dr. Ranjana Advani
MD
Stanford, CA
Dr. Kambiz Afrasiabi
M.D.
Anaheim, CA
Dr. Mark Agulnik
MD
Los Angeles, CA
Dr. Weiyun Ai
MD
San Francisco, CA
Dr. Shafqat Akhtar
MD
Red Bluff, CA
Compare Medical Oncology Physician nationally: see state-by-state distribution →
Before you book an appointment
Use this federal record as your verification checklist, not as a recommendation.
- Confirm the NPI record is current in the official CMS registry, providers update their own NPPES details, and moves can lag. Verify this NPI
- Check the active license and any disciplinary history with the California medical board, federal registration is not a license check. Credential verification guide
- Weigh a second option: compare this provider with a nearby Medical Oncology Physician peer on Medicare volume and prescribing patterns. Compare providers
Medicare Part D and MIPS figures describe practice patterns in federal programs only, they are not quality ratings, and PlainDoctor does not rate, rank, or recommend providers.
Healthcare Guides
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How to Find a Doctor
Step-by-step guide to choosing a provider
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Medical Specialties Explained
Who treats what and how specialties differ
Understanding Medicare Claims Data
What prescribing data reveals about a provider
In-Network vs Out-of-Network
How insurance networks affect your costs
Telehealth Guide
Virtual care options and coverage in 2026
Explore California
Frequently Asked Questions
What is Cy Stein, MD's specialty? ▼
Cy Stein, MD specializes in Medical Oncology Physician and practices in Duarte, California. Credentials: MD.
How much does Cy Stein, MD prescribe under Medicare Part D? ▼
In 2023, Cy Stein, MD wrote 77 Medicare Part D claims totaling $14K in drug costs for N/A beneficiaries.
Where is Cy Stein, MD located? ▼
Cy Stein, MD is located at 1500 DUARTE RD, Duarte, CA, 91010. Phone: (626) 471-3890.
What is Cy Stein, MD's NPI number? ▼
Cy Stein, MD's National Provider Identifier (NPI) is 1871673350, issued on 10/17/2006.
How many Medical Oncology Physician providers are there in the US? ▼
There are 3,815 Medical Oncology Physician providers across 53 states in the US. The average Medical Oncology Physician provider writes 689 Medicare Part D claims per year.
What drugs does Cy Stein, MD prescribe most often? ▼
Based on 2023 Medicare Part D data, Cy Stein, MD's most frequently prescribed drugs include Methotrexate, Duloxetine Hcl. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Cy Stein, MD accept Medicare? ▼
Cy Stein, MD appears in CMS Medicare data with 77 Part D claims and N/A Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Cy Stein, MD's credentials? ▼
Cy Stein, MD's NPI is 1871673350 with credentials MD. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.
Data Sources
View source datasets and methodology notes
- Provider Directory
- CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
- Specialty Classification
- NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
- Prescribing Data
- CMS Medicare Part D Prescriber Public Use File (2023). Includes claims, drug costs, beneficiaries, and opioid prescribing rates.
- Limitations
- Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.
See our complete data methodology for details on how we collect and process government data.
Data as of April 2026 (NPPES) / 2023 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).
Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology
Compiled from official public sources by the PlainDoctor editorial team.
Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of May 2026.