Image-guided dose-escalated radiation therapy for localized prostate cancer with helical tomotherapy

Toxicity of dose-escalated radiotherapy up to 84 Gy for prostate cancer

PURPOSE

The outcome of radiotherapy (RT) for prostate cancer (PCA) depends on the delivered dose. While the evidence for dose-escalated RT up to 80 gray (Gy) is well established, there have been only few studies examining dose escalation above 80 Gy. We initiated the present study to assess the safety of dose escalation up to 84 Gy.

METHODS

In our retrospective analysis, we included patients who received dose-escalated RT for PCA at our institution between 2016 and 2021. We evaluated acute genitourinary (GU) and gastrointestinal (GI) toxicity as well as late GU and GI toxicity.

RESULTS

A total of 86 patients could be evaluated, of whom 24 patients had received 80 Gy and 62 patients 84 Gy (35 without pelvic and 27 with pelvic radiotherapy). Regarding acute toxicities, no > grade 2 adverse events occurred. Acute GU/GI toxicity of grade 2 occurred in 12.5%/12.5% of patients treated with 80 Gy, in 25.7%/14.3% of patients treated with 84 Gy to the prostate only, and in 51.9%/12.9% of patients treated with 84 Gy and the pelvis included. Late GU/GI toxicity of grade ≥ 2 occurred in 4.2%/8.3% of patients treated with 80 Gy, in 7.1%/3.6% of patients treated with 84 Gy prostate only, and in 18.2%/0% of patients treated with 84 Gy pelvis included (log-rank test p = 0.358).

CONCLUSION

We demonstrated that dose-escalated RT for PCA up to 84 Gy is feasible and safe without a significant increase in acute toxicity. Further follow-up is needed to assess late toxicity and survival.

Hybrid Tomo-Helical and Tomo-Direct radiotherapy for localized prostate cancer

PURPOSE

The aim of the study is to present a new planning approach to provide better planning target volume (PTV) coverage and reduce bladder and rectum dose with hybrid Tomo-Helical (TH)/Tomo-Direct (TD) radiotherapy (RT) for localized prostate cancer (LPC).

METHODS

Twenty-five LPC patients were included in this retrospective study. TH plans, TD plans, and hybrid TH/TD plans were created. Lateral beams were used for the hybrid TD plan and the prescribed dose was 70 Gy in 28 fractions (hybrid plans were combined 45 Gy/ 18 fxs for TH and 25 Gy/10 fxs for TD). Doses of PTV (D2%, D98%, D50%, homogeneity index (HI), conformity index (CI), coverage) and organs at risk (OARs) (V50%, V35%, V25%, V5%, and V95%) were analyzed. The Wilcoxon signed-rank test was used to analyze the difference in dosimetric parameters. p-Value < 0.05 was considered statistically significant.

RESULTS

TH plans showed better CI, and target coverage (p < 0.01) than TD and hybrid plans in all patient plan evaluations. However, TD plans D2%, D98%, and D50% doses were better than TH and hybrid plans. The HI values were similar between the three plans. Significant reductions in bladder and rectum V50%, V35%, and V25% doses (p < 0.001) were observed with hybrid plans compared to TH and TD. Penile bulb V95% and bowel V5% doses were better in the hybrid plans. Left and right femoral head V5% doses were higher in the hybrid plan compared to others (p < 0.001).

CONCLUSION

Concurrently hybrid TH/TD RT plan can be a good option to reduce the doses of the rectum and bladder in the RT of LPC.

Comparison of helical tomotherapy with multi-field intensity-modulated radiotherapy treatment plans using simultaneous integrated boost in high-risk prostate cancer

Purpose: The aim of this study is to compare the dosimetric results of Helical Tomotherapy (HT) and Multi-field IMRT treatment plans using a Simultaneous Integrated Boost (SIB) technique in the treatment of High-Risk Prostate Cancer (HRPCa) with pelvic nodal radiation.

Methods: Seventeen patients planned with HT and 7,8 and 9 fields IMRT were investigated. All plans were designed with the prescribed dose of 54.0 Gy to the PTVln while simultaneously delivering 74.0 Gy to the PTVPS in 30 fractions. Dosimetric data of PTV and OARs were compared.

Results: HT gives a better CI and HI of PTVPS compared to multi-field IMRT plans. HT plans significantly improved target coverage (HT:0.95 vs multi-field IMRT: 0.52, 0.49 and 0.49 respectively, p < 0.001). Bladder mean dose(Gy) (HT: 45.6 vs multi-field IMRT: 53.6, 53.3 and 52.7 respectively, p = 0.004) and D66%(Gy) dose (HT: 35.3 vs multi-field IMRT: 46.7, 47.0 and 44.9 respectively, p = 0.006) were lower in HT. But multi-field IMRT plans significantly reduced the rectum volume receiving more than 75 Gy; (HT V75% (%) 2.7 vs multi-field IMRT 0.8, 1.4 and 0.9 respectively, p = 0.008). HT provided better sparing of the right and left femoral head receiving a mean dose. The penile bulb and small bowel doses were the highest in HT compared with multi-field IMRT.

Conclusions: HT achieved better dose distribution to target compared to multi-field IMRT. This study suggests HT as a reasonable option for the treatment of HRPCa patients.

How Has Prostate Cancer Radiotherapy Changed in Italy between 2004 and 2011? An Analysis of the National Patterns-Of-Practice (POP) Database by the Uro-Oncology Study Group of the Italian Society of Radiotherapy and Clinical Oncology (AIRO)

Simple Summary

This is a safety and efficacy analysis from a very large dataset of patients affected by localized prostate cancer having received radiotherapy with or without concomitant androgen deprivation therapy in twelve academic and non-academic Italian Institutions. The aim of this retrospective "real life" study was to provide additional data on clinical presentation, diagnostic workup, radiation therapy management and toxicity as collected within the framework of POP III. Though the usual limitations for a retrospective analysis apply, it nevertheless may expand the current knowledge in this area showing the progress of radiation therapy techniques and clinical outcomes in the period between 2004 and 2011 after a significant period of follow up.

Abstract

Background and purpose: Two previous “Patterns Of Practice” surveys (POP I and POP II), including more than 4000 patients affected by prostate cancer treated with radical external beam radiotherapy (EBRT) between 1980 and 2003, established a “benchmark” Italian data source for prostate cancer radiotherapy. This report (POP III) updates the previous studies. Methods: Data on clinical management and outcome of 2525 prostate cancer patients treated by EBRT from 2004 to 2011 were collected and compared with POP II and, when feasible, also with POP I. This report provides data on clinical presentation, diagnostic workup, radiation therapy management, and toxicity as collected within the framework of POP III. Results: More than 50% of POP III patients were classified as low or intermediate risk using D’Amico risk categories as in POP II; 46% were classified as ISUP grade group 1. CT scan, bone scan, and endorectal ultrasound were less frequently prescribed. Dose-escalated radiotherapy (RT), intensity modulated radiotherapy (IMRT), image guided radiotherapy (IGRT), and hypofractionated RT were more frequently offered during the study period. Treatment was commonly well tolerated. Acute toxicity improved compared to the previous series; late toxicity was influenced by prescribed dose and treatment technique. Five-year overall survival, biochemical relapse free survival (BRFS), and disease specific survival were similar to those of the previous series (POP II). BRFS was better in intermediate- and high-risk patients treated with ≥ 76 Gy. Conclusions: This report highlights the improvements in radiotherapy planning and dose delivery among Italian Centers in the 2004–2011 period. Dose-escalated treatments resulted in better biochemical control with a reduction in acute toxicity and higher but acceptable late toxicity, as not yet comprehensively associated with IMRT/IGRT. CTV-PTV margins >8 mm were associated with increased toxicity, again suggesting that IGRT—allowing for tighter margins—would reduce toxicity for dose escalated RT. These conclusions confirm the data obtained from randomized controlled studies.