Favorable outcomes in locally advanced and node positive prostate cancer patients treated with combined pelvic IMRT and androgen deprivation therapy

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.

Tolerability of concurrent external beam radiotherapy and [177Lu]Lu-PSMA-617 for node-positive prostate cancer in treatment naïve patients, phase I study (PROQURE-I trial)

BACKGROUND

Prostate cancer patients with locoregional lymph node disease at diagnosis (N1M0) still have a limited prognosis despite the improvements provided by aggressive curative intent multimodal locoregional external beam radiation therapy (EBRT) with systemic androgen deprivation therapy (ADT). Although some patients can be cured and the majority of patients have a long survival, the 5-year biochemical failure rate is currently 29-47%. [¹⁷⁷Lu]Lu-PSMA-617 has shown impressive clinical and biochemical responses with low toxicity in salvage setting in metastatic castration-resistant prostate cancer. This study aims to explore the combination of standard EBRT and ADT complemented with a single administration of [¹⁷⁷Lu]Lu-PSMA-617 in curative intent treatment for N1M0 prostate cancer. Hypothetically, this combined approach will enhance EBRT to better control macroscopic tumour localizations, and treat undetected microscopic disease locations inside and outside EBRT fields.

METHODS

The PROQURE-I study is a multicenter prospective phase I study investigating standard of care treatment (7 weeks EBRT and 3 years ADT) complemented with one concurrent cycle (three, six, or nine GBq) of systemic [¹⁷⁷Lu]Lu-PSMA-617 administered in week two of EBRT. A maximum of 18 patients with PSMA-positive N1M0 prostate cancer will be included. The tolerability of adding [¹⁷⁷Lu]Lu-PSMA-617 will be evaluated using a Bayesian Optimal Interval (BOIN) dose-escalation design. The primary objective is to determine the maximum tolerated dose (MTD) of a single cycle [¹⁷⁷Lu]Lu-PSMA-617 when given concurrent with EBRT + ADT, defined as the occurrence of Common Terminology Criteria for Adverse Events (CTCAE) v 5.0 grade three or higher acute toxicity. Secondary objectives include: late toxicity at 6 months, dosimetric assessment, preliminary biochemical efficacy at 6 months, quality of life questionnaires, and pharmacokinetic modelling of [¹⁷⁷Lu]Lu-PSMA-617.

DISCUSSION

This is the first prospective study to combine EBRT and ADT with [¹⁷⁷Lu]Lu-PSMA-617 in treatment naïve men with N1M0 prostate cancer, and thereby explores the novel application of [¹⁷⁷Lu]Lu-PSMA-617 in curative intent treatment. It is considered likely that this study will confirm tolerability as the combined toxicity of these treatments is expected to be limited. Increased efficacy is considered likely since both individual treatments have proven high anti-tumour effect as mono-treatments.

TRIAL REGISTRATION

ClinicalTrials, NCT05162573 . Registered 7 October 2021.

Utility of index lesion volume assessed by multiparametric MRI combined with Gleason grade for assessment of lymph node involvement in patients with high-risk prostate cancer

PURPOSE

We examined the potential predictors of lymph node involvement and evaluated whether index lesion volume assessed using multiparametric magnetic resonance imaging is associated with lymph node involvement among patients with high-risk prostate cancer.

METHODS

Extended pelvic lymph node dissection was used to evaluate patients with lymph node involvement. We retrospectively analyzed consecutive 102 patients with high-risk prostate cancer who underwent extended pelvic lymph node dissection at our institution between 2011 and 2017. To evaluate the index lesion volume at multiparametric magnetic resonance imaging (mrV), lesions were manually contoured on each T2-weighted axial slice in combination with diffusion-weighted and dynamic contrast-enhanced magnetic resonance imaging and integrated using image analysis software. Logistic regression analysis was performed to identify predictors of lymph node involvement.

RESULTS

The median mrV was 1.4 ml (range 0-30.1 ml), and the median number of resected lymph nodes was 14 (range 7-38). Among 102 patients, 28 (28%) had lymph node involvement. Multivariate analysis identified significant predictors of lymph node involvement as follows: biopsy Gleason-grade group 5 (odds ratio = 17.2; 95% confidence interval, 2.1-299.0; P = 0.005), preoperative mrV (odds ratio = 1.14; 95% confidence interval, 1.02-1.30; P = 0.025) and percentage of positive cores with highest Gleason-grade group (odds ratio = 1.05; 95% confidence interval, 1.01-1.10; P = 0.005). Lymph node involvement was prevalent (69%) among tumors with Gleason-grade group 5 and mrV ≥3.4 ml, but was infrequently (10%) present among tumors with Gleason-grade group ≤4 and mrV <3.4 ml.

CONCLUSIONS

The combination of biopsy Gleason-grade and mrV may serve as a useful tool to stratify patients according to their risk of nodal metastases.

Prediction of metastatic prostate cancer by prostate-specific antigen in combination with T stage and Gleason Grade: Nationwide, population-based register study

The objective was to investigate the proportion of men with metastatic prostate cancer in groups defined by T stage, Gleason Grade Group (GGG) and serum levels of prostate-specific antigen (PSA) and if PSA can be used to rule in metastatic prostate cancer when combined with T stage and GGG. We identified 102,076 men in Prostate Cancer data Base Sweden 4.0 who were diagnosed with prostate cancer in 2006–2016. Risk of metastases was assessed for PSA stratified on T stage and five-tiered GGG. For men who had not undergone bone imaging, we used multiple imputation to classify metastatic prostate cancer. Advanced T stage, high GGG and high PSA were related to bone metastases. For example: only 79/38 190 (0.2%) of men with T1-2 and GGG 1 had PSA above 500 ng/mL, and 29/79 (44%) of these men had metastases; whereas 1 154/7 018 (16%) of men with T3-4 and GGG 5 had PSA above 500 ng/ml and 1 088/1 154 (94%) of these men had metastases. However, no PSA cut-off could accurately identify the majority of men with metastatic prostate cancer (i.e. high sensitivity) while also correctly classifying most men without metastasis (i.e. high specificity). In conclusion, these results support the use of imaging to confirm bone metastases in men with advanced prostate cancer as no PSA level in combination with T stage and GGG could accurately rule in metastatic prostate cancer and thereby safely omit bone imaging.

The Horse is at the Stable Door: Management of N1M0 Prostate Cancer

Pelvic lymph node involvement in prostate cancer is a significant poor prognostic factor with very little evidence on the optimal management options for these patients. It is estimated that lymph node-positive patients make up 12% of newly diagnosed prostate cancer and this figure is expected to rise with the advancement and increasing use of novel imaging. The controversy around this subgroup of patients is whether this is an intermediary stage before disseminated disease and hence amenable to curative treatment options. Systemic therapies have been the mainstay of treatment for these patients for decades, but in recent years, studies have emerged supporting the addition of local therapy. This review will focus on the current multimodal management approach for clinical and pathological lymph node-positive prostate cancer with a focus on radiotherapy options and aims to provide the rationale for a curative approach with a combination of local and systemic therapy.

Radiation-related Lymphopenia after Pelvic Nodal Irradiation for Prostate Cancer

Purpose

Given the uncertainty with regard to the effectiveness of pelvic nodal irradiation (PNI) for prostate cancer, we aimed to determine whether patients with prostate cancer who are treated with PNI are at a higher risk of developing radiation-related lymphopenia (RRL).

Methods and materials

The electronic charts of 886 consecutive patients treated with radiation therapy for prostate cancer between 2006 and 2018 at our institution were retrospectively analyzed. Qualifying patients were those with total lymphocyte counts within 1 year before and 3 to 24 months after the start of radiation therapy. Lymphopenia was the primary outcome, and overall survival and biochemical progression-free survival were secondary outcomes.

Results

Thirty-six patients with and 95 patients without PNI qualified for inclusion. In the PNI cohort, 61.1% of patients developed RRL (median follow-up total lymphocyte count < 1000 cells/μL) versus 26.3% of non-PNI patients (P < .001). On univariate analysis, initial prostate-specific antigen level, baseline lymphopenia, treatment modality, PNI status, increased planned target volume, and androgen deprivation therapy administration were all significant predictors of RRL (P < .05). On multivariate analysis, PNI status was a significant predictor of RRL (hazard ratio [HR], 3.42; 95% confidence interval [CI], 1.22-9.61; P < .001), as were initial prostate-specific antigen values (HR, 1.05; 95% CI, 1.00-1.11; P = .006) and baseline lymphopenia (HR, 8.32; 95% CI, 2.19-31.6; P = .007). RRL was not predictive for biochemical progression-free survival, distant metastasis, or overall survival on multivariate analysis, but the number of events was likely insufficient for these analyses.

Conclusions

The higher risk of RRL among patients with PNI comports with other papers that show that increased treatment volumes are associated with higher rates of RRL. Mounting evidence for the adverse effects of RRL on clinical outcomes supports the significance of our findings and suggests that further studies are needed on RRL as a potential harm of PNI that may affect the interpretation of results from clinical trials of PNI.

Phase I/IIa clinical trial of a novel hTERT peptide vaccine in men with metastatic hormone-naive prostate cancer

In newly diagnosed metastatic hormone-naive prostate cancer (mPC), telomerase-based immunotherapy with the novel hTERT peptide vaccine UV1 can induce immune responses with potential clinical benefit. This phase I dose escalation study of UV1 evaluated safety, immune response, effects on prostate-specific antigen (PSA) levels, and preliminary clinical outcome. Twenty-two patients with newly diagnosed metastatic hormone-naïve PC (mPC) were enrolled; all had started androgen deprivation therapy and had no visceral metastases. Bone metastases were present in 17 (77%) patients and 16 (73%) patients had affected lymph nodes. Three dose levels of UV1 were given as intradermal injections combined with GM-CSF (Leukine®). Twenty-one patients in the intention-to-treat population (95%) received conformal radiotherapy. Adverse events reported were predominantly grade 1, most frequently injection site pruritus (86.4%). Serious adverse events considered possibly related to UV1 and/or GM-CSF included anaphylactic reaction in two patients and thrombocytopenia in one patient. Immune responses against UV1 peptides were confirmed in 18/21 evaluable patients (85.7%), PSA declined to <0.5 ng/mL in 14 (64%) patients and in ten patients (45%) no evidence of persisting tumour was seen on MRI in the prostatic gland. At the end of the nine-month reporting period for the study, 17 patients had clinically stable disease. Treatment with UV1 and GM-CSF gave few adverse events and induced specific immune responses in a large proportion of patients unselected for HLA type. The intermediate dose of 0.3 mg UV1 resulted in the highest proportion of, and most rapid UV1-specific immune responses with an acceptable safety profile. These results warrant further clinical studies in mPC.