PTC CLINIC
Information for Healthcare Professionals

The main advantage of proton therapy is the significantly better dose distribution of the radiation dose to critical organs. Doses applied to the bladder and rectum are typically 25-50% compared to published doses for modern photon techniques. In the case of pelvic radiotherapy, the doses to the abdominal organs are 5-10% of the prescribed dose. The results of proton radiotherapy are better than recent published work for photon radiotherapy.

• Spratt et al. describe 5-year biochemical relapse-free survival in intermediate-risk prostate cancer treated with either external radiotherapy using the IMRT technique or the combination of IMRT and brachytherapy at the level of approximately 90% for IMRT (81.4% after 7 years) and approximately 95% in the combination of IMRT and BRT (92% after 7 years). Grade 2 toxicity or higher (CTCAE v. 4) reached the following levels at the evaluation after 7 years: GU (genitourinary) – 19.6% for IMRT and 21.2% for the combined treatment; grade 3 GU toxicity was 3.1 and 1.4%, respectively; GI (Gastrointestinal) – grade 2 and above 4.6 and 4.1%, respectively; grade 3 0.4% and 1.4%, respectively.
• Odrážka et al. describe 5-year biochemical control of prostate cancer treated with IMRT at the level of 86%, 89% and 82% for low-risk, medium-risk and high-risk, respectively. The late toxicity (RTOG/FC-LENT) grade 2 or higher was: GU and GI 17.7% and 22.4%, respectively.

Particle radiotherapy in the treatment of prostate cancer achieves the best dose distributions of available radiotherapy techniques. Prospective non-randomized studies demonstrate its high efficacy and very low toxicity, and patients treated at PTC confirm these data.

Table 1: Comparison of effectiveness and toxicity of individual radiotherapeutic methods and the treatment of low-risk prostate cancer.

As evidenced by the data provided in the table, the undesirable effects after photon therapy are significantly higher than after proton radiotherapy.

Figure 1 and Table 2 are examples of an irradiation plan and dose distribution to individual organs. It is clear that a significantly lower or zero dose is applied to healthy tissue during proton radiotherapy.

Figure 1: Example of a plan: photon IMRT vs. proton IMPT.

Table 2: Dose for each structure/organ.