The Oncology Drug Pipeline

Oncology is the most profitable specialty in Medicare — and the most flagged for impossible billing volumes. Of the roughly 1,100 individual providers we identified billing more than 400 services per working day, 532 are hematology-oncology or medical oncology doctors — nearly half of all impossible providers. Twenty-four oncologists each billed over $5.0M with more than 80% of their revenue coming from drug administration codes, combining for $171.0M in total payments.

The ASP+6% Incentive

Medicare reimburses physician-administered drugs under Part B at ASP+6% — the Average Sales Price plus a 6% markup. This means the more expensive the drug, the more profit the doctor makes. A $100 drug earns $6 in markup. A $10,000 drug earns $600. For the same 15-minute injection.

Cancer drugs are among the most expensive medications in existence. A single dose of immunotherapy can cost Medicare $10,000–$30,000. When oncologists' billing is 80–97% drug codes, the financial incentive is clear: the practice revenue depends on which drugs they choose and how many patients they infuse.

This doesn't mean every high-billing oncologist is doing something wrong. Chemotherapy infusions genuinely involve multiple drug codes per patient visit — a patient might receive 3–5 different drug administrations in a single session. But when a single doctor bills 3.3K services per working day, the math starts to strain credulity.

The Numbers

We filtered Medicare provider data for hematology-oncology and medical oncology doctors with more than 60% of their billing in drug administration codes. We found 559 oncologists matching this pattern. The top 20 by total payments:

The Dreisbach Question

Luke Dreisbach, a hematology-oncology specialist in Rancho Mirage, California, tops the list for services per day: 3.3K services per working day. His total Medicare payments reached $9.8M, with 90% coming from drug administration codes.

Even accounting for multiple drug codes per patient — a typical chemo infusion might generate 3–5 separate billing codes — 3.3K services per day would require treating hundreds of patients daily. At 5 codes per patient, that's still 660 patients per day. At 8 hours, that's 82 patients per hour, or one every 44 seconds.

This likely reflects a large multi-provider practice billing under a single NPI, or a billing structure where all infusion services are attributed to the supervising oncologist. But the pattern raises questions about Medicare's "incident-to" billing rules, which allow services performed by nurses or PAs to be billed under a physician's NPI at higher reimbursement rates.

Wichita: An Oncology Hotspot

Three oncologists in Wichita, Kansas appear in the top 20: Bassam Mattar ($7.2M), Dennis Moore ($6.7M), and Pavan Reddy ($6.7M). Together, they billed over $20.0M — all with 84–89% drug billing. Wichita is a city of 400,000 people with three oncologists each billing like they serve a major metropolitan area.

Maryland also stands out: William Sharfman in Lutherville ($9.1M, 97.2% drugs), Mei Tang in Baltimore ($6.9M, 91.9% drugs), Justin Kucinski in Salisbury ($6.9M, 93.5% drugs), and David Smith in Easton ($6.4M, 92.2% drugs). Four Maryland oncologists in the top 20, with a combined $29.0M.

Why Oncology Dominates the Impossible List

Of roughly 1,100 individual providers billing more than 400 services per working day, 532 are oncologists — 48% of all impossible-volume providers come from a single specialty group. No other specialty comes close. Rheumatology is second with 288, and it shares the same drug-heavy billing model (biologics like Remicade and Rituxan).

The structural reason is straightforward: oncology is built on drugs. An office visit generates a single billing code worth $100–200. A chemotherapy infusion generates multiple drug codes worth thousands each. A busy oncology practice with dozens of infusion chairs running simultaneously will naturally produce enormous service counts — but the question is whether one doctor can meaningfully supervise all of those infusions.

The Policy Problem

The ASP+6% formula has been criticized for decades. The Medicare Payment Advisory Commission (MedPAC) has repeatedly recommended switching to a flat fee for drug administration, which would eliminate the incentive to choose expensive drugs. Congress has not acted.

The Inflation Reduction Act of 2022 began Medicare drug price negotiations for Part D drugs, but Part B drugs — the physician-administered drugs that drive oncology billing — remain largely untouched. As long as the financial incentive favors expensive drugs, oncology will continue to dominate Medicare's high-billing landscape.

The 559 oncologists we identified billing more than 60% in drug codes represent a structural feature of how Medicare pays for cancer care — not necessarily fraud. But when the incentives are this powerful, and the billing volumes this extreme, the line between aggressive practice and billing abuse becomes dangerously thin.