Acute Toxicity Profiles of Hypofractionated Adjuvant and Salvage Radiation Therapy After Radical Prostatectomy: Results of a Prospective Study

Evidences on the Use of Hypofractionation in Postoperative/Salvage Radiotherapy for Prostate Cancer: Systematic Review of the Literature and Recent Developments

BACKGROUND

Radical prostatectomy (RP) is one possible curative treatment for localized prostate cancer. Despite that, up to 40% of patients will later relapse. Currently, post-operative radiotherapy (PORT) courses deliver 1.8-2 Gy daily to reach a total dose ranging between 64 and 74 Gy, completed in 7-8 weeks. Several articles reported encouraging data in terms of the effectiveness and the related toxicities using hypofractionation schedules. The objective of the present systematic review was to evaluate the clinical outcomes and toxicity of the use of hypofractionation in adjuvant/salvage prostate cancer treatments.

METHODS

Medline was searched via PubMed and Scopus from inception to July 2024 to retrieve studies on hypofractionation in adjuvant/salvage prostate cancer treatments. This study was conducted under PRISMA guidelines.

RESULTS

A total of 139 articles were identified from the initial search. Subsequently, the 139 studies were reviewed by title and abstract. Ninety-five studies were excluded due to being either abstracts or articles not available in English. In the second step, the full texts of 44 studies were reviewed. Eleven studies were excluded for being reviews, study protocols, or focused on SBRT treatments. Finally, 33 studies were included in our analysis, with a total number of 4269 patients. Of the 33 selected studies, 20 were retrospective trials and 11 were phase I/II prospective trials, while 2 studies were prospective phase III trials. The follow-up ranged from 18 to 217 months. Failure-free survival, for those with the longer follow-up, ranged between 85% and 91% at 3 years, 47 and 78.6% at 5 years and 51.5% at 10 years. Genitourinary (GU) and gastrointestinal acute toxicity was mild to moderate with similar rates across the normofractionated and hypofractionated groups. Acute grade-3 GU toxicity events were unusual, occurring in less than 4% of the cases overall.

CONCLUSION

The present study is the first systematic review of the literature that includes the first two randomized phase III studies published in the literature. Hypofractionated treatment has been shown to be safe, effective, with moderate toxicity and not inferior to conventional RT, with good biochemical control rates.

Moderate hypofractionated radiotherapy to the prostate bed with or without pelvic lymph nodes: a prospective trial

Background

Hypofractionated radiotherapy in the treatment of prostate cancer has been widely studied. However, in the postoperative setting it has been less explored. The objective of this prospective study is to evaluate the safety and efficacy of hypofractionated radiotherapy in postoperative prostate cancer.

Materials and methods

A prospective study was designed to include patients with prostate cancer with an indication of postoperative radiotherapy as adjuvant or salvage. A hypofractionated radiotherapy scheme of 51 Gy in 17 fractions was performed with the possibility of treating the pelvis at a dose of 36 Gy in 12 fractions sequentially. Safety was evaluated based on acute and late toxicity [according to the Radiation Therapy Oncology Group (RTOG) scale and Common Terminology Criteria Adverse Events (CTCAE) v4.03], International Prognostic Scoring System (IPSS) over time, and quality of life.

Results

From August 2020 to June 2022, 31 patients completed treatment and were included in this report. 35.5% of patients received elective treatment of the pelvic nodal areas. Most patients reported minimal or low acute toxicity, with an acute gastrointestinal (GI) and genitourinary (GU) grade 3 or greater toxicity of 3.2% and 0%, respectively. The evolution in time of the IPSS remained without significant differences (p = 0.42). With the exception of a significant improvement in the domains of hormonal and sexual symptoms of the Expanded Prostate Cancer Index Composite (EPIC) questionnaire, the rest of the domains [EPIC, European Organization for Research and Treatment of Cancer (EORTC) Core quality of life questionnaire (C-30) and Prostate Cancer module (PR-25)] were maintained without significant differences over time. With a follow-up of 15.4 months, late GI and GU grade 2 toxicity was reported greater than 0% and 9.6%, respectively.

Conclusions

Hypofractionated radiotherapy in postoperative prostate cancer appears to be safe with low reports of relevant acute or late toxicity. Further follow-up is required to confirm these results.

Trial registration

The protocol was approved by the accredited Medical Ethical Committee of Pontificia Universidad Católica de Chile. All participants accepted and wrote informed consent.

Radiation therapy after radical prostatectomy is associated with higher other-cause mortality

PURPOSE

To test the association between external beam radiotherapy (EBRT) after radical prostatectomy (RP) vs RP only on rates of other-cause mortality (OCM) in men with prostate cancer (PCa).

PATIENTS AND METHODS

Within the 2004-2016 Surveillance, Epidemiology, and End Results database, we identified 181,849 localized PCa patients, of whom 168,041 received RP only vs 13,808 who received RP + EBRT. Cumulative incidence plots displayed OCM between RP vs RP + EBRT after propensity score matching for age, PSA, clinical T- and N-stages, and biopsy Gleason scores. Multivariable competing risks regression models addressed OCM, accounting prostate cancer-specific mortality (CSM) as a competing event. Stratifications were made according to low- vs intermediate- vs high-risk groups and additionally according to age groups of ≤ 60, 61-70, and ≥ 71 years, within each risk group.

RESULTS

In low-, intermediate-, and high-risk patients, RP + EBRT rates were 2.7, 5.4 and 17.0%, respectively. After matching, 10-year OCM rates between RP and RP + EBRT were 7.7 vs 16.2% in low-, 9.4 vs 13.6% in intermediate-, and 11.4 vs 13.5% in high-risk patients (all p < 0.001), which, respectively, resulted in multivariable HR of 2.1, 1.3, and 1.2 (all p < 0.001). In subgroup analyses, excess OCM was recorded in low-risk RP + EBRT patients of all age groups (all p ≤ 0.03), but only in the older age group in intermediate-risk patients (61-70 years, p = 0.03) and finally, only in the oldest age group in high-risk patients (≥ 71 years, p = 0.02).

CONCLUSION

Excess OCM was recorded in patients exposed to RT after RP. Its extent was most pronounced in low-risk patients, decreased in intermediate-risk patients, and was lowest in high-risk patients.

Tomotherapy-based moderate hypofractionation for localized prostate cancer: a mono-institutional analysis

Background

To date, few studies have been published on image-guided helical tomotherapy (HT) in a moderate hypofractionation of localized PCa. We report outcome and toxicity of localized PCa patients treated with HT-based moderate hypofractionated radiotherapy.

Materials and methods

76 patients were retrospectively analyzed. A total dose of 60 Gy (20 × 3 Gy) or 67.5 Gy (25 × 2.7 Gy) was prescribed. The χ² test was used to analyze associations between toxicity and dosimetric and clinical parameters. The Cox proportional hazard regression model was used for multivariate analysis. Kaplan-Meier method was used for survival analysis.

Results

median follow-up was 42.26 months [interquartile (IQR), 23-76). At 4-year, overall survival (OS) and metastasis-free survival (MFS) were 91% and 89%, respectively. At multivariate analysis, smoking habitude was associated with MFS [hazard ratio (HR) 7.32, 95% CI: 1.57-34.16, p = 0.011]. Acute and late grade ≥ 2 gastro-intestinal (GI) toxicity was observed in 6.5% and 2.6% of patients, respectively. Acute and late grade ≥ 2 genito-urinary (GU) toxicity were 31.5% and 3.9%. Four-year late GI and GU grade ≥ 2 toxicity were 3% and 7%, respectively. Acute GI toxicity was associated with statins medication (p = 0.04) and androgen deprivation therapy (p = 0.013). Acute GU toxicity was associated with the use of anticoagulants (p = 0.029) and antiaggregants (p = 0.013).

Conclusions

HT-based moderate hypofractionation shows very low rates of toxicity. Smoking habitude is associated with the risk of developing metastases after radical treatment for localized PCa.

Salvage hypofractionated accelerated versus standard radiotherapy for the treatment of biochemical recurrence after radical prostatectomy (SHARE): the protocol of a prospective, randomized, open-label, superiority, multi-institutional trial

BACKGROUND

While several phase III trials have investigated the role of hypofractionated radiotherapy in the definitive treatment of localized prostate cancer, prospective data reporting the outcomes of hypofractionated radiotherapy in the postoperative treatment setting are sparse. Therefore, this study is designed to assess the efficacy and treatment-related toxicity of hypofractionated salvage radiotherapy for the treatment of biochemical recurrence in men who underwent radical prostatectomy. The primary objective of this trial is to investigate whether hypofractionated radiotherapy improves biochemical control compared with conventionally fractionated radiotherapy. In addition, treatment-related toxicity, quality of life, and survival will be evaluated as secondary endpoints.

METHODS

In this prospective, randomized, multi-institutional trial (the SHARE study), patients with intermediate- or high-risk prostate cancer will be randomized to receive either hypofractionated radiotherapy (65 Gy in 2.5-Gy fractions) or conventionally fractionated radiotherapy (66 Gy in 2-Gy fractions). Prostate bed irradiation or elective pelvic nodal irradiation including the prostate bed will be performed using intensity-modulated radiotherapy and daily image guidance. Treatment efficacy will be assessed using the serum tumor marker prostate-specific antigen, and toxicity will be evaluated through both physician- and patient-reported outcomes. Quality of life will also be investigated.

DISCUSSION

This study is designed to demonstrate whether hypofractionated radiotherapy is beneficial in terms of biochemical control and toxicity compared with standard salvage radiotherapy. If hypofractionated radiotherapy is shown to be superior to conventionally fractionated radiotherapy, it will mean that improved biochemical control can be achieved, accompanied by greater patient convenience and more efficient use of medical resources.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03920033. Registered on 18 April 2019.

Hypofractionated Postprostatectomy Radiation Therapy for Prostate Cancer to Reduce Toxicity and Improve Patient Convenience: A Phase 1/2 Trial

PURPOSE

The phase 1 portion of this multicenter, phase 1/2 study of hypofractionated (HypoFx) prostate bed radiation therapy (RT) as salvage or adjuvant therapy aimed to identify the shortest dose-fractionation schedule with acceptable toxicity. The phase 2 portion aimed to assess the health-related quality of life (QoL) of using this HypoFx regimen.

METHODS AND MATERIALS

Eligibility included standard adjuvant or salvage prostate bed RT indications. Patients were assigned to receive 1 of 3 daily RT schedules: 56.6 Gy in 20 Fx, 50.4 Gy in 15 Fx, or 42.6 Gy in 10 Fx. Regional nodal irradiation and androgen deprivation therapy were not allowed. Participants were followed for 2 years after treatment with outcome measures based on prostate-specific antigen levels, toxicity assessments (Common Terminology Criteria for Adverse Events, v4.0), QoL measures (the Expanded Prostate Cancer Index Composite [EPIC] and EuroQol EQ-5D instruments), and out-of-pocket costs.

RESULTS

There were 32 evaluable participants, and median follow-up was 3.53 years. The shortest dose-fractionation schedule with acceptable toxicity was determined to be 42.6 Gy in 10 Fx, with most patients (23) treated with this schedule. Grade 3 genitourinary (GU) and gastrointestinal (GI) toxicities occurred in 3 patients and 1 patient, respectively. There was 1 grade 4 sepsis event. Higher dose to the hottest 25% of the rectum was associated with increased risk of grade 2+ GI toxicity; no dosimetric factors were found to predict for GU toxicity. There was a significant decrease in the mean bowel, but not bladder, QoL score at 1 year compared with baseline. Prostate-specific antigen failure occurred in 34.3% of participants, using a definition of nadir plus 2 ng/mL. Metastases were more likely to occur in regional lymph nodes (5 of 7) than in bones (2 of 7). The mean out-of-pocket cost for patients during treatment was $223.90.

CONCLUSIONS

We identified 42.6 Gy in 10 fractions as the shortest dose-fractionation schedule with acceptable toxicity in this phase 1/2 study. There was a higher than expected rate of grade 2 to 3 GU and GI toxicity and a decreased EPIC bowel QoL domain with this regimen. Future studies are needed to explore alternative adjuvant/salvage HypoFx RT schedules after radical prostatectomy.

Moderate hypofractionated post-prostatectomy radiation therapy is feasible and well tolerated: experience from a single tertiary cancer centre

PURPOSE

Conventional post-prostatectomy radiation therapy comprises 6.5-8 weeks of treatment, therefore, hypofractionated and shortened schemes arouse increasing interest. We describe our experience regarding feasibility and clinical outcome of a post-prostatectomy moderate hypofractionated image-guided radiotherapy schedule MATERIALS AND METHODS: From Oct 2015-Mar 2020, 113 patients, median age of 62 years-old (range 45-76) and prostate adenocarcinoma of low risk (30%), intermediate risk (49%) and high risk (21%) were included for adjuvant (34%) or salvage radiation therapy (66%) after radical prostatectomy (RP). All patients underwent radiotherapy with image-guided IMRT/VMAT to a total dose of 62.5 Gy in 2.5 Gy/fraction in 25 fractions. Sixteen patients (14%) received concomitant androgen deprivation therapy.

RESULTS

With a median follow-up of 29 months (range 3-60 months) all patients but three are alive. Eleven patients (10%) developed exclusive biochemical relapse while 19 patients (17%) presented macroscopically visible relapse: prostatectomy bed in two patients (2%), pelvic lymph nodes in 13 patients (11.5%) and distant metastases in four patients (4%). The 3 years actuarial rates for OS, bFRS, and DMFS were 99.1, 91.1 and 91.2%, respectively. Acute and late tolerance was satisfactory. Maximal acute genitourinary (AGU) toxicity was G2 in 8% of patients; maximal acute gastrointestinal (AGI) toxicity was G2 in 3.5% of patients; maximal late genitourinary (LGU) toxicity was G3 in 1% of patients and maximal late gastrointestinal (LGI) toxicity was G2 in 2% of patients. There were no cases of severe acute or late toxicity. No relationship was found between acute or late GI/GU adverse effects and dosimetric parameters, age, presence of comorbidities or concomitant treatments.

CONCLUSIONS

Hypofractionated radiotherapy (62.5 Gy in 25 2.5 Gy fractions) is feasible and well tolerated with low complication rates allowing for a moderate dose-escalation that offers encouraging clinical results for biochemical control and survival in patients with prostate cancer after radical prostatectomy.

Stereotactic body radiotherapy for adrenal oligometastasis in lung cancer patients

OBJECTIVE

To report our experience on stereotactic body radiotherapy (SBRT) in adrenal metastases from lung cancer.

METHODS

37 oligometastatic lung cancer patients with 38 adrenal metastases submitted to SBRT were retrospectively analyzed. SBRT was delivered by volumetric modulated arc therapy (VMAT) or helical tomotherapy (HT). Primary study end point was local recurrence-free survival (LR-FS) and secondary end points were distant-progression free survival (d-PFS) and overall survival (OS).

RESULTS

Median age was 67 years and primary tumor was non-small-cell lung cancer in 27 (73%) and small-cell lung cancer in 10 (27%) patients. Adrenal metastases were in the left side in 66% cases. Median prescribed dose was 30 Gy in 5 fractions for a median biologically equivalent dose (α/β ratio 10  Gy, BED10) of 48 Gy. Most patients (62%) were submitted to SBRT alone, while the others (38%) received chemo-, immune- or target- therapies. Median follow-up was 10.5 months, median OS 16 months and median d-PFS 3 months. 27 (70%) patients obtained a local control with a median LR-FS of 32 months. LR-FS was significantly related to BED10 with a better LC with BED10 ≥72 Gy, 1- and 2 year LR-FS rates were 54.1±11.6% and 45±12.7% vs 100 and 100% for BED ≤59.5 Gy and BED ≥72 Gy, respectively (p = 0.05). There was no severe toxicity.

CONCLUSION

SBRT was effective and safe in lung cancer adrenal metastases. A dose-response relationship was found between BED10 >72 Gy and better local control. No significant toxicity was registered thanks to the respect of dose constraints and suspension of chemo- and target-therapies.

ADVANCES IN KNOWLEDGE

SBRT with a BED10 >72 Gy is an effective treatment for adrenal oligometastatic lung cancer patients.