History, current status and prospects of proton and heavy ion radiotherapy for tumors
Abstract
Proton and heavy ions were discovered a century ago. Compared with conventional X-ray beams, proton and heavy ion beams exhibit unique superiorities in radiophysical dose distribution. Upon penetration into biological media, these beams release energy abruptly at a specific depth to form a very concentrated high-dose region, followed by a rapid dose drop-off. This distinctive dose distribution characteristic was defined as the "Bragg peak" phenomenon, which enables proton and heavy ion beams to effectively spare peritumoral normal tissues. Proton beams possess slightly higher radiobiological effectiveness than X-rays, with a relative biological effectiveness (RBE) value of 1.1-1.2. Currently, carbon ion beam is the predominant heavy ion beam adopted in clinical radiotherapy. Carbon ion beam exerts a powerful tumor-killing capacity with an RBE of 2.0-3.0. Notably, carbon ion beam demonstrates a prominent tumor eradication effect against X-ray-resistant tumors, particularly hypoxic tumor cells. The oxygen enhancement ratio (OER) of carbon ion beam is approximately 2, lower than the OER of 3 in conventional X-rays. Globally, there are 128 operational proton therapy centers and 17 heavy ion therapy centers. As of 2024, more than 350 000 patients worldwide have been treated by proton radiotherapy, and over 50 000 patients by heavy ion radiotherapy. The Shanghai Proton and Heavy Ion Center/Proton and Heavy Ion Center, Fudan University Shanghai Cancer Center is the first center of this kind in China. It was officially launched for clinical practice in May 2015. Over the past 11 years, the center has established proton and carbon ion beam radiotherapy techniques and the standardized operating procedures for a variety of tumors. By May 2026, the center had treated a cumulative total of 9 317 patients, among whom 75% received carbon ion beam or carbon ion beam boost irradiation combined with X-ray or proton radiotherapy. Clinical outcomes have shown that carbon ion beam radiotherapy yielded significantly better efficacy than X-ray radiotherapy in the following cancers: recurrent nasopharyngeal carcinoma, glioblastoma and unresectable locally advanced pancreatic cancer. For early-stage and locally advanced non-small cell lung cancers, primary liver cancers, and localized prostate carcinoma, carbon ion beam radiotherapy achieved therapeutic efficacy equivalent to X-ray radiotherapy, but with substantially fewer radiation-related adverse events. Because of high capital investment, proton radiotherapy cannot replace conventional X-ray radiotherapy in the short term. However, with the gradual reduction in facility costs, proton radiotherapy will become a main modality for radiotherapy in China in the near future. Moreover, carbon ion beam radiotherapy has superior clinical efficacy over both X-ray and proton radiotherapy, and is considered a promising modality for the future, but due to the enormous capital investment requirements, carbon ion beam radiotherapy can only be carried out in a small number of tertiary hospitals, and will not become the mainstream radiotherapy modality in the near future.
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BibTeX
@article{guoliang2026history,
title = {{History, current status and prospects of proton and heavy ion radiotherapy for tumors}},
author = {JIANG Guoliang},
journal = {Zhongguo aizheng zazhi},
year = {2026},
month = sep,
url = {http://www.china-oncology.com/zh/article/doi/10.19401/j.cnki.1007-3639.2026.09.001/},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - History, current status and prospects of proton and heavy ion radiotherapy for tumors
AU - JIANG Guoliang
PY - 2026
DA - 2026/09/01
JO - Zhongguo aizheng zazhi
UR - http://www.china-oncology.com/zh/article/doi/10.19401/j.cnki.1007-3639.2026.09.001/
AB - Proton and heavy ions were discovered a century ago. Compared with conventional X-ray beams, proton and heavy ion beams exhibit unique superiorities in radiophysical dose distribution. Upon penetration into biological media, these beams release energy abruptly at a specific depth to form a very concentrated high-dose region, followed by a rapid dose drop-off. This distinctive dose distribution characteristic was defined as the "Bragg peak" phenomenon, which enables proton and heavy ion beams to effectively spare peritumoral normal tissues. Proton beams possess slightly higher radiobiological effectiveness than X-rays, with a relative biological effectiveness (RBE) value of 1.1-1.2. Currently, carbon ion beam is the predominant heavy ion beam adopted in clinical radiotherapy. Carbon ion beam exerts a powerful tumor-killing capacity with an RBE of 2.0-3.0. Notably, carbon ion beam demonstrates a prominent tumor eradication effect against X-ray-resistant tumors, particularly hypoxic tumor cells. The oxygen enhancement ratio (OER) of carbon ion beam is approximately 2, lower than the OER of 3 in conventional X-rays. Globally, there are 128 operational proton therapy centers and 17 heavy ion therapy centers. As of 2024, more than 350 000 patients worldwide have been treated by proton radiotherapy, and over 50 000 patients by heavy ion radiotherapy. The Shanghai Proton and Heavy Ion Center/Proton and Heavy Ion Center, Fudan University Shanghai Cancer Center is the first center of this kind in China. It was officially launched for clinical practice in May 2015. Over the past 11 years, the center has established proton and carbon ion beam radiotherapy techniques and the standardized operating procedures for a variety of tumors. By May 2026, the center had treated a cumulative total of 9 317 patients, among whom 75% received carbon ion beam or carbon ion beam boost irradiation combined with X-ray or proton radiotherapy. Clinical outcomes have shown that carbon ion beam radiotherapy yielded significantly better efficacy than X-ray radiotherapy in the following cancers: recurrent nasopharyngeal carcinoma, glioblastoma and unresectable locally advanced pancreatic cancer. For early-stage and locally advanced non-small cell lung cancers, primary liver cancers, and localized prostate carcinoma, carbon ion beam radiotherapy achieved therapeutic efficacy equivalent to X-ray radiotherapy, but with substantially fewer radiation-related adverse events. Because of high capital investment, proton radiotherapy cannot replace conventional X-ray radiotherapy in the short term. However, with the gradual reduction in facility costs, proton radiotherapy will become a main modality for radiotherapy in China in the near future. Moreover, carbon ion beam radiotherapy has superior clinical efficacy over both X-ray and proton radiotherapy, and is considered a promising modality for the future, but due to the enormous capital investment requirements, carbon ion beam radiotherapy can only be carried out in a small number of tertiary hospitals, and will not become the mainstream radiotherapy modality in the near future.
SN - 1007-3639
ER -