Photon- and Proton-Mediated Biological Effects: What Has Been Learned?

Area of Science:

• Oncology
• Radiation Oncology
• Biophysics

Background:

• Patient response to radiation therapy varies significantly, with outcomes ranging from pronounced positive responses to disease progression.
• Understanding the systemic and local effects of radiation therapy on tumor cells and the tumor microenvironment is crucial for improving treatment efficacy.
• Photon therapy is a well-established radiotherapy modality, while proton therapy is an emerging technology with promising dosimetric and biological advantages.

Purpose of the Study:

• To review and compare the biological effects of photon and proton irradiation in cancer therapy.
• To elucidate the mechanisms of tumor cell damage, interaction with the tumor microenvironment, and effects on angiogenesis for both radiation types.
• To evaluate the toxicological profiles and potential adverse events associated with photon versus proton therapy.

Main Methods:

• Systematic literature review of over 100 relevant sources.
• Analysis of local effects of photon and proton therapy.
• Examination of mechanisms of tumor cell damage, tumor microenvironment interactions, and angiogenesis.

Main Results:

• Proton therapy demonstrates potentially favorable toxicological profiles compared to photon irradiation.
• The reduced damage to healthy tissues surrounding the tumor by protons is attributed to their physical and biological properties.
• Both photon and proton therapies share generally similar radiobiological effects, but proton therapy may lead to fewer local and systemic adverse events.

Conclusions:

• Proton therapy offers a potentially safer alternative to photon therapy due to its ability to spare healthy tissues.
• The physical and biological characteristics of protons contribute to a reduced risk of side effects.
• Further research into proton therapy could lead to improved patient outcomes and reduced treatment-related morbidity.