Stereotactic pelvic radiotherapy with HDR boost for dose escalation in intermediate and high-risk prostate cancer (SPARE): Efficacy, toxicity and quality of life

Safety of Ultrahypofractionated Pelvic Nodal Irradiation in the Definitive Management of Prostate Cancer: Systematic Review and Meta-analysis

PURPOSE

This systematic review and meta-analysis aimed to evaluate the evidence for ultrahypofractionated pelvic nodal irradiation in patients with prostate cancer, with a focus on reported acute and late toxicities.

METHODS AND MATERIALS

A comprehensive search was conducted in 5 electronic databases (PubMed, Scopus, Web of Science, Cochrane Library, ClinicalTrials.gov) from inception until March 23, 2023. Eligible publications included patients with intermediate- and high-risk and node-positive prostate cancer who underwent elective or therapeutic ultrahypofractionated pelvic nodal irradiation. Primary outcomes included the presence of grade ≥2 rates of acute and late gastrointestinal and genitourinary toxicity based on the Common Terminology Criteria for Adverse Events or Radiation Therapy Oncology Group scales. Quality assessment was performed using National Institutes of Health tools for noncontrolled beforeand after (single arm) clinical trials, as well as single-arm observational studies. Because all outcomes were categorical variables, proportion was calculated to estimate the effect size and compare the outcomes after the intervention.

RESULTS

We identified 16 publications that reported the use of ultrahypofractionated radiation therapy to treat the pelvis in prostate cancer. Seven publications met our criteria and were included in the meta-analysis, including 417 patients. The median total dose to the pelvic lymph nodes was 25 Gy (range, 25-28.5 Gy), with a median of 5 fractions. The prostate received a median dose of 40 Gy (range, 35-47.5 Gy). All studies used androgen deprivation therapy for a median duration of 18 months. The median follow-up period was 3 years (range, 0.5-5.6 years). The rates of acute grade ≥2 gastrointestinal and genitourinary toxicity were 8% (95% CI, 1%-15%) and 29% (95% CI, 18%-41%), respectively. For late grade ≥2 gastrointestinal and genitourinary toxicity, the rates were 13% (95% CI, 5%-21%) and 29% (95% CI, 17%-42%), respectively.

CONCLUSIONS

Ultrahypofractionated pelvic nodal irradiation appears to be a safe approach in terms of acute and late genitourinary and gastrointestinal toxicity.

Comparison of four-year toxicities and local control of ultra-hypofractionated vs moderate-hypofractionated image guided prostate radiation with HDR brachytherapy boost: A phase I-II single institution trial

Purpose/Objectives

To analyze the long term efficacy and safety of an ultra-hypofractionated (UHF) radiation therapy prostate treatment regimen with HDR brachytherapy boost (BB) and compare it to moderate-hypofractionated regimens (MHF).

Materials/Methods

In this single arm, prospective monocentric study, 28 patients with intermediate risk prostate cancer were recruited in an experimental treatment arm of 25 Gy in 5 fractions plus a 15 Gy HDR BB. They were then compared to two historical control groups, treated with either 36 Gy in 12 fractions or 37.5 Gy in 15 fractions with a similar HDR BB. The control groups included 151 and 311 patients respectively. Patient outcomes were reported using the International Prostate Symptom Score (IPSS) and Expanded Prostate Index Composite (EPIC-26) questionnaires at baseline and at each follow-up visit.

Results

Median follow-up for the experimental arm was 48.5 months compared to 47 months and 60 months compared to the 36/12 and 37,5/15 groups respectively. The IPSS and EPIC scores did not demonstrate any significant differences in the gastrointestinal or genitourinary domains between the three groups over time. No biochemical recurrence occurred in the UHF arm as defined by the Phoenix criterion.

Conclusion

The UHF treatment scheme with HDR BB seems equivalent to standard treatment arms in terms of toxicities and local control. Randomized control trials with larger cohorts are ongoing and needed to further confirm our findings.

Two-fraction stereotactic ablative radiotherapy with simultaneous boost to MRI-defined dominant intra-prostatic lesion - Results from the 2SMART phase 2 trial

PURPOSE

This is the first report of the 2SMART Phase II trial evaluating the safety of two-fraction stereotactic ablative radiotherapy (SABR) with focal boost to magnetic resonance imaging (MRI) defined dominant intra-prostatic lesion (DIL) for localised prostate cancer.

MATERIALS AND METHODS

Men with low or intermediate risk prostate cancer were eligible for the study. The gross tumour volume (GTV) was MRI-defined DIL, and the clinical target volume (CTV) was entire prostate gland. The planning target volume (PTV) was a 2 mm expansion anteroposterior and lateral, and 2.5 mm superoinferior. The prescribed dose was 32 Gy to GTV, and 26 Gy to CTV. Primary endpoint was minimal clinically important change (MCIC) in quality of life (QOL) within 3-months of SABR, assessed using the EPIC-26 questionnaire. Secondary endpoints were acute and late toxicities (assessed using CTCAEv4), PSA nadir, and biochemical failure (based on Phoenix criteria).

RESULTS

Thirty men were enrolled in the study - 2 (7%) had low-risk and 28 (93%) had intermediate risk prostate cancer. The median follow-up was 44 months (range:39-49 months). The median PSA nadir was 0.25 ng/mL, with median time to nadir of 37 months. One patient (3%) had biochemical failure at 44 months post-treatment. Ten (33%), six (20%), and three (10%) men had acute MCIC in urinary, bowel, and sexual QOL domains respectively. No acute or late grade ≥ 3 urinary or bowel toxicities were observed.

CONCLUSION

This novel protocol of two-fraction prostate SABR with MRI-defined DIL boost is a safe approach for dose-escalation, with minimal impact on acute QOL and no grade ≥ 3 toxicities.

Acute and late toxicity of prostate-only or pelvic SBRT in prostate cancer: A Comparative Study

OBJECTIVE

To compare the urinary and gastrointestinal toxicity with or without the inclusion of pelvic nodal regions in patients treated with extreme hypofractionated stereotactic radiotherapy (SBRT) for prostate cancer.

METHODS

Patients treated with definitive SBRT for non-metastatic adenocarcinoma prostate were identified from prospectively maintained institutional database, and details of radiotherapy volume, dose, acute and late adverse effects were analyzed. Symptoms of acute (within 90 days of completing SBRT) and late gastrointestinal and urinary toxicities were graded using CTCAE version 5.0. Each symptom was scored according to the worst reported grading during treatment and follow-up period. Cumulative toxicity rates between prostate-only SBRT (PO-SBRT) and whole pelvic SBRT (WP-SBRT) were compared using chi-square test.

RESULTS

Total 220 patients were analyzed (PO-SBRT=118, WP-SBRT=102), with a median follow-up of 28 months (IQR 14-40). Most patients had locally advanced disease (PO-SBRT 60% high risk and 40% intermediate risk, WP-SBRT 79% node positive and 21% high risk). Median SBRT dose was 36.25Gy (IQR 35-36.25) to the prostate (EQD2=90.6Gy, a/b=1.5Gy) and simultaneous integrated 25Gy to the pelvis (EQD2=46.3Gy) in five fractions on alternate days. No grade 3-4 acute toxicities were observed except one grade 3 urinary obstruction (PO-SBRT). WP-SBRT was associated with significantly higher acute grade 2 gastrointestinal toxicity (29.4% vs 14.7%, p=0.008) and late grade 2 urinary toxicity (45.6% vs 25.0%, p=0.003). Both the groups had low incidence of late grade 3 toxicities (urinary 2.5%, gastrointestinal 1%).

CONCLUSION

WP-SBRT was associated with significantly higher acute gastrointestinal and late urinary toxicity as compared to PO-SBRT, though overall incidence of severe toxicity was low.

Elective nodal ultra hypofractionated radiation for prostate cancer: Safety and efficacy from four prospective clinical trials

BACKGROUND AND PURPOSE

The role of elective nodal irradiation (ENI) in localized prostate cancer (PCa) is controversial. With increasing use of SBRT to the prostate, data is needed regarding the safety and efficacy of ENI using ultra-hypofractionated radiation (UHRT).

MATERIALS AND METHODS

Between 2013-2020, 4 prospective clinical trials of intermediate or high-risk PCa receiving dose-escalated RT to the prostate (via HDR brachytherapy or SBRT boost) and ENI using UHRT (25 Gy in 5 weekly fractions) were conducted. Primary endpoints included acute genitourinary and gastrointestinal toxicities (CTCAE v3.0/4.0), and secondary endpoints included late genitourinary and gastrointestinal toxicities, patient-reported quality of life (EPIC) and biochemical failure (Phoenix definition).

RESULTS

One-hundred sixty-five patients were enrolled, of whom 98 (59%) had high-risk disease. ADT was used in 141 (85%). Median follow-up was 38 months (IQR 10-63). The worst acute genitourinary and gastrointestinal toxicities respectively were 48% and 7.5% for grade 2, and 2.7% and 0% for grade 3. Cumulative incidence of late grade 2+ genitourinary and gastrointestinal toxicities at 36 months were 58% and 11.3% and for late grade 3+ toxicities were 1% and 0%, respectively. No grade 4+ acute or late toxicities were observed. Bowel and sexual toxicity significantly worsened up to 1-year compared to baseline. Over time, urinary (p < 0.0001), bowel (p = 0.0018) and sexual (p < 0.0001) scores significantly improved. The 3-year biochemical recurrence-free survival was 98%.

CONCLUSION

ENI using UHRT is associated with low incidence of grade 3+ toxicity, while grade 1-2 acute genitourinary and gastrointestinal toxicity is common. Randomized phase 3 trials are needed.