Clinical outcomes of definitive whole pelvic radiotherapy for clinical lymph node metastatic prostate cancer

Volumetric Modulated Arc Therapy for High-Risk and Very High-Risk Locoregional Prostate Cancer in the Modern Era: Real-World Experience from an Asian Cohort

This study retrospectively evaluates the clinical outcomes of definitive volumetric modulated arc therapy (VMAT) for high-risk or very high-risk locoregional prostate cancer patients from an Asian institution. Consecutive patients who received VMAT (76 Gy in 38 fractions) between January 2017 and June 2022 were included. Whole pelvic radiotherapy (WPRT) (46 Gy in 23 fractions) was employed for clinically node-negative disease (cN0) and a Roach estimated risk of ≥15%, as well as simultaneous integrated boost (SIB) of 55-57.5 Gy to node-positive (cN1) disease. The primary endpoint was biochemical relapse-free survival (BRFS). Secondary endpoints included radiographic relapse-free survival (RRFS), metastasis-free survival (MFS) and prostate cancer-specific survival (PCSS). A total of 209 patients were identified. After a median follow-up of 47.5 months, the 4-year actuarial BRFS, RRFS, MFS and PCSS were 85.2%, 96.8%, 96.8% and 100%, respectively. The incidence of late grade ≥ 2 genitourinary (GU) and gastrointestinal (GI) toxicity were 15.8% and 11.0%, respectively. No significant difference in cancer outcomes or toxicity was observed between WPRT and prostate-only radiotherapy for cN0 patients. SIB to the involved nodes did not result in increased toxicity. International Society of Urological Pathology (ISUP) group 5 and cN1 stage were associated with worse RRFS (p < 0.05). PSMA PET-CT compared to conventional imaging staging was associated with better BRFS in patients with ISUP grade group 5 (p = 0.039). Five-year local experience demonstrates excellent clinical outcomes. PSMA PET-CT staging for high-grade disease and tailored pelvic irradiation based on nodal risk should be considered to maximize clinical benefit.

Local Therapy on Clinically Lymph Node-positive Prostate Cancer: A Systematic Review and Meta-analysis

CONTEXT

Patients with clinically lymph node-positive (cN1) prostate cancer (PCa) are traditionally regarded to have metastatic disease, and the role of local therapy (LT) in their treatment remains unclear.

OBJECTIVE

To evaluate the outcomes of cN1 PCa patients treated with LT, and secondarily to compare between different modalities of LT, including radiotherapy (RT) and radical prostatectomy (RP).

EVIDENCE ACQUISITION

A bibliographic search was performed using Medline, Embase, and the Cochrane Library to identify studies comparing the survival outcomes of cN1 PCa patients treated with LT (RT or RP) with those who did not receive any form of LT (observation or androgen deprivation therapy alone). The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) recommendations were followed. Survival outcomes of the addition of LT were assessed using a random-effect model.

EVIDENCE SYNTHESIS

A total of 8522 patients across eight studies were included. LT significantly improved overall survival (OS) across all time points from 2 to 10 yr compared with patients without LT, most notably providing a durable benefit in 10-yr OS (odds ratio [OR]: 1.49, 95% confidence interval [CI] 1.06-2.10). Both RT and RP were associated with benefits to both OS and recurrence-free survival, with no significant difference in OS between both modalities in medium-term follow-up (4-yr OR: 0.76, 95% CI 0.41-1.40, p = 0.19).

CONCLUSIONS

Regardless of modality, the use of LT in cN1 patients improved OS. Future studies should aim to identify patients who could benefit from LT and include more comprehensive survival data including biochemical recurrence.

PATIENT SUMMARY

In this study, we evaluated the outcomes of clinically lymph node-positive (cN1) prostate cancer (PCa) patients treated with local therapy (LT) and compared between different modalities of LT, including radiotherapy (RT) and radical prostatectomy (RP). We found that the addition of LT for cN1 PCa patients leads to a significant improvement in survival outcomes, most notably for overall survival, with no significant difference between RT and RP.

Impact of prostate radiotherapy on survival outcomes in clinically node-positive prostate cancer: A multicentre retrospective analysis

PURPOSE

To evaluate clinical outcomes for cN1M0 prostate cancer treated with varied modalities.

MATERIALS AND METHODS

Men with radiological stage cN1M0 prostate cancer on conventional imaging, treated from 2011-2019 with various modalities across four centres in the UK were included. Demographics, tumour grade and stage, and treatment details were collected. Biochemical and radiological progression-free survival (bPFS, rPFS) and overall survival (OS) were estimated using Kaplan Meier analyses. Potential factors impacting survival were tested with univariable log-rank test and multivariable Cox-proportional hazards model.

RESULTS

Total 337 men with cN1M0 prostate cancer were included, 47% having Gleason grade group 5 disease. Treatment modalities included androgen deprivation therapy (ADT) in 98.9% men, either alone (19%) or in combinations including prostate radiotherapy (70%), pelvic nodal radiotherapy (38%), docetaxel (22%), or surgery (7%). At median follow up of 50 months, 5-year bPFS, rPFS, and OS were 62.7%, 71.0%, and 75.8% respectively. Prostate radiotherapy was associated with significantly higher bPFS (74.1% vs 34.2%), rPFS (80.7% vs 44.3%) and OS (86.7% vs 56.2%) at five years (log rank p < 0.001 each). On multivariable analysis including age, Gleason grade group, tumour stage, ADT duration, docetaxel, and nodal radiotherapy, benefit of prostate radiotherapy persisted for bPFS [HR 0.33 (95% CI 0.18-0.62)], rPFS [HR 0.25 (0.12-0.51)], and OS [HR 0.27 (0.13-0.58)] (p < 0.001 each). Impact of nodal radiotherapy or docetaxel was not established due to small subgroups.

CONCLUSION

Addition of prostate radiotherapy to ADT in cN1M0 prostate cancer yielded improved disease control and overall survival independent of other tumour and treatment factors.

Predictors of Outcomes in Patients With Clinically Lymph Node Positive Prostate Cancer After Definitive Radiotherapy

BACKGROUND/AIM

Studies have suggested that benefits of definitive radiotherapy might be limited to specific patients in clinically lymph node positive (cN1) prostate cancer (PC). However, the beneficial subgroup remains to be elucidated. This study aimed to analyze survival outcomes and prognostic factors after definitive radiotherapy and androgen deprivation therapy (definitive RT+ADT) in these patients and to define subgroups of patients who would benefit from definitive RT+ADT the most.

PATIENTS AND METHODS

A total of 60 patients with cN1 PC treated with definitive RT+ADT in a single tertiary hospital were accrued. Their clinicopathological variables were analyzed and a new subgroup was identified based on statistically significant variables.

RESULTS

At a median follow-up of 31 months, ADT duration ≥24 months (p=0.043, HR=0.26) and positive biopsy core ≥75% (p=0.044, HR=5.29) showed significant relationships with distant metastasis-free survival. Overall survival showed significant relationships with ADT duration ≥24 months (p=0.002, HR=0.06) and number of lymph node (LN) metastases ≥4 (p=0.019, HR=7.17). For prognostic subgroup analysis, patients were divided into three risk groups: low-risk group (LN metastases <4 and ADT ≥24 months), high-risk group (LN metastases ≥4 and ADT <24 months), and intermediate-risk group (all remaining cases). Three-year actuarial overall survival rates for the low-, intermediate-, and high-risk groups were 100%, 93.3%, and 45.7%.

CONCLUSION

ADT duration and number of LN metastases were important prognostic factors in patients with cN1 PC receiving definitive RT+ADT, with low-risk cN1 PC patients showing better outcomes than others.

Ten‐year outcomes of whole‐pelvic intensity‐modulated radiation therapy for prostate cancer with regional lymph node metastasis

BACKGROUND

Management of pelvic node-positive prostate cancer has been challenging and controversial. We conducted a study to evaluate the outcomes of whole-pelvic (WP) simultaneous integrated boost (SIB) intensity-modulated radiation therapy (IMRT) combined with androgen deprivation therapy (ADT).

METHODS

A total of 67 consecutive patients with cT1c-4N1M0 prostate cancer were definitively treated by WP SIB-IMRT. Neoadjuvant ADT (median: 8.3 months) was administered in all cases. WP SIB-IMRT was designed to simultaneously deliver 78, 66.3, and 58.5 Gy in 39 fractions to the prostate plus seminal vesicles, metastatic lymph nodes (LNs), and the pelvic LN region, respectively. Adjuvant ADT (median: 24.7 months) was administered in 66 patients.

RESULTS

The median follow-up period was 81.6 months (range: 30.5-160.7). Biochemical relapse-free, overall, and prostate cancer-specific survival rates at 10 years were 59.8%, 79.6%, and 86.3%, respectively. Loco-regional recurrence was not observed. Being in International Society of Urological Pathology grade group 5 and having a posttreatment detectable nadir prostate-specific antigen (PSA) level (≥0.010 ng/ml) were significantly associated with worse prostate cancer-specific survival and progression of castration resistance. The 10-year cumulative incidence rates of grade 2 and 3 late toxicities were, respectively, 1.5% and 0% for genitourinary, 0% and 1.5% for gastrointestinal events. No grade 4 acute or late toxicities were observed.

CONCLUSIONS

WP SIB-IMRT can be safely administered to patients with pelvic node-positive prostate cancer. Since grade group 5 and detectable nadir PSA levels are risks for castration resistance, we may need to increase the intensity of treatment for such cases.

[Metachronous oligometastatic prostate cancer-the more the better or only local treatment?]

BACKGROUND

Prostate cancer metastases may occur at diagnosis (de novo) or metachronous after treatment for localized disease.

OBJECTIVE

To describe location, prognosis, and individual treatment concepts for metachronous oligometastatic prostate cancer.

MATERIALS AND METHODS

Analysis of current treatment guidelines and literature for hormone sensitive, metachronous metastatic prostate cancer.

RESULTS

Modern imaging modalities lead to earlier diagnosis of metachronous oligometastatic prostate cancer, which offers the opportunity to develop metastasis-directed treatment concepts. Oligometastatic recurrence may occur in locoregional lymph nodes (N1) or as distant disease (M1). N1 disease is predominantly treated by salvage lymph node dissection or radiation. Distant metastasis may be radiated in order to delay systemic treatment. The combination of androgen deprivation and novel androgen receptor-targeted drugs such as apalutamide or enzalutamide are associated with a significant survival benefit compared to castration alone in bone or visceral oligometastatic metachronous disease.

CONCLUSION

Metachronous oligometastatic prostate cancer is heterogeneous with slow progression compared to men with high volume metastasis. Individual treatment concepts may decrease risk of progression and, thus, delay time to medical treatment. Multimodal approaches are currently being evaluated in clinical trials.

Elective nodal radiotherapy in prostate cancer

In patients with prostate cancer who have a high risk of pelvic nodal disease, the use of elective whole pelvis radiotherapy is still controversial. Two large, randomised, controlled trials (RTOG 9413 and GETUG-01) did not show a benefit of elective whole pelvis radiotherapy over prostate-only radiotherapy. In 2020, the POP-RT trial established the role of elective whole pelvis radiotherapy in patients who have more than a 35% risk of lymph node invasion (known as the Roach formula). POP-RT stressed the importance of patient selection. In patients with cN1 (clinically node positive) disease or pN1 (pathologically node positive) disease, the addition of whole pelvis radiotherapy to androgen deprivation therapy significantly improved survival compared with androgen deprivation therapy alone, as shown in large, retrospective studies. This patient population might increase in the future because use of the more sensitive prostate-specific membrane antigen PET-CT will become the standard staging procedure. Additionally, the SPORTT trial suggested a benefit of whole pelvis radiotherapy in biochemical recurrence-free survival in the salvage setting. A correct definition of the upper field border, which should include the bifurcation of the abdominal aorta, is key in the use of pelvic radiotherapy. As a result of using modern radiotherapy technology, severe late urinary and intestinal toxic effects are rare and do not seem to increase compared with prostate-only radiotherapy.

Intensity-Modulated Radiation Therapy with Simultaneous Integrated Boost for Clinically Node-Positive Prostate Cancer: A Single-Institutional Retrospective Study

Simple Summary

Recently, it has been shown that radiation therapy (RT) together with androgen-depletion therapy (ADT) might be more beneficial compared with ADT alone for clinically node-positive (cN1) prostate cancer. However, there are a limited number of studies that have addressed specific RT techniques and analyzed their clinical results. The present study was a retrospective analysis of cN1 prostate cancer patients treated with intensity-modulated radiation therapy with simultaneous integrated boost (SIB-IMRT), in addition to ADT, in our hospital. The present study suggests that ADT plus SIB-IMRT for cN1 prostate cancer treatment was safe and effective, was well tolerated, and had acceptable rates of late toxicity. Further prospective multicenter studies would be required to confirm the robustness of the present results.

Abstract

This study aimed to evaluate clinical outcomes and the toxicity of intensity-modulated radiation therapy with simultaneous integrated boost (SIB-IMRT) combined with androgen-deprivation therapy for clinically node-positive (cN1) prostate cancer. We retrospectively analyzed 97 patients with cN1 prostate cancer who received SIB-IMRT between June 2008 and October 2017 at our hospital. The prescribed dosages delivered to the prostate and seminal vesicle, elective node area, and residual lymph nodes were 69, 54, and 60 Gy in 30 fractions, respectively. Kaplan–Meier analysis was used to determine 5-year biochemical relapse-free survival (bRFS), relapse-free survival (RFS), overall survival (OS), and prostate cancer-specific survival (PCSS). Toxicity was evaluated using the Common Terminology Criteria for Adverse Events ver. 4.0. Over a median follow-up duration of 60 months, the 5-year bRFS, RFS, OS, and PCSS were 85.1%, 88.1%, 92.7% and 95.0%, respectively. Acute Grade 2 genito-urinary (GU) and gastro-intestinal (GI) toxicities were observed in 10.2% and 2.1%, respectively, with no grade ≥3 toxicities being detected. The cumulative incidence rates of 5-year Grade ≥2 late GU and GI toxicities were 4.7% and 7.4%, respectively, with no Grade 4 toxicities being detected. SIB-IMRT for cN1 prostate cancer demonstrated favorable 5-year outcomes with low incidences of toxicity.

Clinical outcomes of definitive whole pelvic radiotherapy for clinical lymph node metastatic prostate cancer

Background

In this study, we aim to present the clinical outcomes of radiotherapy (RT) in clinical pelvic lymph node‐positive prostate cancer (cN1) patients. We also analyze the prognostic factors with focus on RT dose escalation to metastatic lymph nodes (LN).

Methods

We retrospectively analyzed the data from cN1 patients who were treated with definitive RT and androgen deprivation therapy (ADT) between June 2004 and February 2016. All patients received localized irradiation to the prostate region and whole pelvis irradiation. Some patients received intensity‐modulated radiation therapy with RT dose escalation to metastatic LN. Univariate analyses using log‐rank test were performed to find prognostic factors between patient subgroups.

Results

Fifty‐one consecutive patients were identified. The median follow‐up period for all patients was 88 (range 20‐157) months. Primary Gleason pattern and LN RT dose were statistically significant prognostic factors for relapse‐free survival (RFS) and distant metastasis‐free survival (DMFS). Especially, RT dose escalation (60 Gy or more) to metastatic LN significantly improved RFS and DMFS compared with standard dose RT (4‐year RFS 90.6% vs 82.1%, 7‐year RFS 90.6% vs 58.0%, P = .015; 4‐year DMFS 90.6% vs 82.1%, 7‐year DMFS 90.6% vs 62.8%, P = .023). The following factors were all statistically significant for biochemical relapse‐free survival (BRFS): T stage, LN RT dose, local RT dose, and ADT duration period. Any significantly different toxicity was not seen for each LN or local RT dose except for the incident rate of grade 2 or more acute urinary retention, which was significantly higher in the higher LN RT dose (60 Gy or more) group by the Chi‐square test.

Conclusions

RT dose escalation to metastatic LN in cN1 patients improves BRFS, RFS, and DMFS at 4 and 7 years, without increasing severe adverse events.