Procedures in Office Settings
Proton Therapy for Cancer Patients
A highly targeted form of radiation treatment that concentrates its energy precisely at the tumor — and stops — delivering higher doses to cancer cells while protecting healthy tissue and critical organs.
1954
first use of proton therapy for localized cancer treatment
ZERO
exit dose through tissue beyond the planned cancer target
Understanding Proton Beam Treatment
Proton therapy was first used for localized cancer treatment in 1954 and has continued to be considered an effective treatment modality for primary and additional therapy. Protons are positively charged subatomic particles that can be highly focused to deliver radiation to a specifically planned cancer target.
As the proton beam travels through the body toward its target, it enters with a low dose of radiation, deposits most of its energy in a concentrated burst near the end of the range — at the planned cancer target — and then quickly stops, with no exit dose through tissue beyond the target. This is the defining physical advantage of proton therapy over conventional X-ray radiation.
Why this matters clinically: Because protons stop at the tumor, radiation oncologists can deliver higher doses to the intended cancer target — while critical and sensitive organs and surrounding healthy tissue receive substantially less radiation than with other treatment modalities. The result is more effective treatment with fewer side effects.
Proton Beam vs. Conventional X-Ray Radiation
The key difference between proton therapy and conventional photon (X-ray) radiation is what happens beyond the tumor. Conventional X-ray beams continue traveling through and beyond the tumor, depositing radiation in healthy tissue on the exit side. Proton beams stop at the tumor — delivering their energy precisely where it is needed and nowhere else.
Cancers Treated with Proton Therapy
Proton therapy is particularly valuable for tumors located near critical structures — including the brain, spine, eyes, heart, and major vessels — where minimizing radiation scatter is essential. It is especially beneficial for pediatric patients, whose growing bodies are more sensitive to radiation-related long-term effects.
Pediatric cancers • Head & neck cancers • Brain tumors • Sarcomas
Prostate cancer • Lung cancer • Spinal tumors • Eye tumors
Zero Exit Dose
The proton beam stops at the tumor — no radiation passes through to healthy tissue on the other side.
High Tumor Dose
Concentrated energy delivery allows oncologists to prescribe higher, more effective doses directly to cancer cells.
Fewer Side Effects
Sparing healthy tissue means lower acute toxicity, minimal late effects, and a better quality of life during treatment.
Pediatric Safe
Reduced scatter allows growing bones and organs to develop normally — critical for pediatric patients.
Research & Clinical Outcomes
Two peer-reviewed studies establish the clinical case for proton therapy in pediatric head and neck cancers — documenting lower toxicity, improved quality of life, and better long-term developmental outcomes compared with conventional radiation.
Pediatric - Head & Neck
Proton Therapy for Pediatric Head and Neck Malignancies (Vogel et al., Pediatric Blood & Cancer, 2017)
Proton beam therapy for pediatric head and neck patients produced lower acute toxicity, minimal late toxicity, and improved quality of life compared with conventional radiation approaches. Critically, the use of protons allows pre-adult patients to grow to normal heights — reducing stunted bone growth that can result from conventional radiation exposure to developing skeletal structures.
Quality — Pediatric
Proton Therapy in the Most Common Pediatric Non-CNS Malignancies: Clinical and Dosimetric Outcomes (Sardaro et al., Italian Journal of Pediatrics, 2019)
Rhabdomyosarcoma — the most common soft tissue sarcoma in pediatric patients — is highly malignant and locally invasive. This review confirmed that proton beam therapy for pediatric patients with this and related cancers offers superior dosimetric profiles, delivering effective treatment to the tumor while substantially reducing radiation exposure to surrounding organs and developing tissue.
Racial & Geographic Disparities in Proton Therapy Access
Despite proton therapy's clinical advantages — particularly for pediatric patients — access to this treatment is far from equal. Research documents both racial disparities in who receives proton therapy and geographic disparities in where treatment centers are located, with the burden falling disproportionately on Black, Hispanic, and rural patients.
Key findings: Race, Ethnicity, and Socioeconomic Differences in Incidence of Pediatric Embryonal Tumors (Geris & Spector, Pediatric Blood & Cancer, 2020)
Disparities begin at the point of diagnosis:
-
Hispanic and non-Hispanic Black pediatric patients experience rhabdomyosarcoma more frequently than their non-Hispanic White counterparts.
-
These same populations face compounding barriers to accessing the most advanced treatments — including proton therapy — that are most beneficial for this cancer type.
Key findings: Pediatric Rhabdomyosarcoma Incidence and Survival in the United States (McEvoy et al., Cancer Medicine, 2022)
Even when controlling for other factors, disparities in survival persist:
-
Health equity in survival outcomes is multifactorial, but a key driver is unequal access to care — including access to advanced radiation treatment like proton therapy.
-
Patients who cannot access proton therapy centers are more likely to receive conventional radiation, with higher rates of long-term side effects and developmental harm — particularly for children.
Key findings: Race Disparities in Proton Radiotherapy Use Among Children's Oncology Group Trials (Bitterman et al., JAMA Oncology, 2020)
Perhaps the most striking evidence of the access disparity comes from patients already enrolled in clinical trials:
-
Black patients were less likely than non-Hispanic White patients to receive proton radiotherapy — even when enrolled in national prospective clinical trials where treatment protocols are highly standardized.
-
Patients treated with proton radiotherapy traveled further for treatment — reflecting the sparse and unequal geographic distribution of proton therapy centers across the country.
-
The location of the enrolling institution was strongly associated with whether a patient received proton therapy — meaning where a child is treated determines whether they access the best available care, regardless of what clinical guidelines recommend.
What this means for policy
The unequal distribution of proton therapy centers — and the financial pressures that prevent new centers from opening in underserved communities — means that access to this effective, lower-toxicity treatment remains effectively rationed by geography and race. Protecting reimbursement for office-based and freestanding proton therapy centers is a critical step toward ensuring that all pediatric cancer patients, regardless of background or zip code, can access the treatment that gives them the best chance of survival and a healthy life.
Where a child is treated should not determine whether they receive the best available cancer care. Equitable access to proton therapy requires protecting freestanding center reimbursement.
Proton Therapy Centers Map
