Quick answers
- Does Bruce J. Giantonio accept Medicare assignment?
- Yes. Medicare's clinician data says Bruce J. Giantonio accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
- How many Medicare patients does Bruce J. Giantonio see?
- In 2024, CMS data shows 173 Original Medicare patients and 516 services for Bruce J. Giantonio. This counts Original Medicare only and measures volume, not quality.
- What is Bruce J. Giantonio's NPI number?
- 1255377198. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Medicare activity in 2024
Official CMS public-use data for Bruce J. Giantonio, data year 2024 (released May 21, 2026). It covers Original Medicare (fee-for-service) patients only, not Medicare Advantage or other insurance. It shows volume, not quality or outcomes. CMS hides any count of 10 or fewer patients.
| Original Medicare patients | 173 |
|---|---|
| Services billed to Medicare | 516 |
| Different services or procedures | 13 |
| Participating Medicare provider | Yes |
| Average age of these patients | 75 |
Most frequent services
- Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more (99215)317 services
- Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes (99233)108 services
- Telephone medical discussion with physician, 21-30 minutes (99443)26 services
- Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)16 services
- Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes (99223)16 services
Chronic conditions among these patients
Share of this clinician’s Original Medicare patients with each condition, as published by CMS (it describes the patients, not the care given).
- High blood pressure75%
- Cancer (breast, colorectal, lung, prostate, endometrial or leukemia/lymphoma)72%
- High cholesterol66%
- Ischemic heart disease38%
- Arthritis33%
- Diabetes31%
Hospitals where Bruce J. Giantonio works
Medicare's Facility Affiliation Data lists Bruce J. Giantonio at these hospitals (updated October 2, 2026). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians. Star rating and emergency services: Hospital General Information (CMS), data updated October 26, 2026.
- Brigham and Women's HospitalBoston, MA · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 220110
- Massachusetts General HospitalBoston, MA · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 220071
- Wentworth-Douglass HospitalDover, NH · Acute Care Hospital · Medicare rating: 4 of 5 stars · Emergency services: listed by Medicare · CCN 300018
Practice locations
Addresses where Bruce J. Giantonio is enrolled with Medicare (CMS data updated October 2, 2026).
- 40 2nd AveWaltham, MA 02451 (781) 487‑2900
- 55 Fruit StBoston, MA 02114 (617) 726‑2000
Group practices
Medicare enrollment lists Bruce J. Giantonio as a member of these groups (CMS data updated October 2, 2026).
- Massachusetts General Physicians Organization Inc3,558 clinicians in the group
- The General Hospital Corporation1,267 clinicians in the group
Specialties
- Hematology/Oncologyprimary
Other hematologist-oncologists in Waltham
Clinicians with the same Medicare primary specialty in Waltham, MA — not a recommendation.
Other clinicians in Massachusetts General Physicians Organization Inc
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Georgetown University School Of Medicine |
| Graduation year | 1987 (39 years since medical school) |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| Telehealth | Offers telehealth services |
| NPI (National Provider Identifier) | 1255377198 |
| Corrections | Report an error or suggest an update → |
Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.
Sources
- Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated October 2, 2026, retrieved October 29, 2026
- Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
- National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
- Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
- NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
- Medicare Care Compare — official Medicare tool to look up clinicians