Treatment options in lymph node-positive prostate cancer

Magnetic Resonance Imaging-Guided Cryoablation of Prostate Cancer Lymph Node Metastasis

PURPOSE

To evaluate the safety and effectiveness of magnetic resonance (MR) imaging-guided cryoablation of prostate cancer metastatic lymph nodes (LNs).

MATERIALS AND METHODS

Fifty-two patients with prostate cancer who underwent MR imaging-guided LN ablation from September 2013 to June 2022 were retrospectively reviewed. Of these, 6 patients were excluded because adequate ablation margins (3-5 mm) could not be achieved secondary to adjacent structures. The remaining 46 patients (mean age, 70 years [SD ± 7]) underwent 55 MR imaging-guided cryoablation procedures of metastatic LNs (25 in the pelvic sidewall, 20 within the pelvic region, and 10 in the abdomen) with procedural intent of complete ablation. Locoregional tumor control (ie, technical success in the target LN) was evaluated on initial follow-up positron emission tomography (PET) scans at a mean of 4 months (SD ± 2). Preablation and postablation prostate-specific antigen (PSA) levels were recorded. Imaging follow-up continued until a median of 27.5 months (range: 3-108 months).

RESULTS

Ninety-five percent (52/55) of treated LNs demonstrated no considerable activity on PET scans at initial follow-up at 4 months (SD ± 2). PSA decreased to an undetectable level of <0.1 ng/mL after cryoablation in 14 of 46 (30.4%) patients with corresponding lack of activity in 13 of 46 (28.2%) patients on continued PET imaging follow-up. Only 6 of 55 (10.9%) patients had transient adverse events, which all resolved with no long-term sequalae.

CONCLUSIONS

MR imaging-guided percutaneous cryoablation of metastatic LNs is a safe and technically effective technique for treating metastatic prostate cancer in LNs.

Clinical outcome in metastatic prostate cancer after primary radiotherapy

PURPOSE

To describe a local radio-oncological treatment for patients with prostate cancer that metastasized to either the lymph nodes or distant regions.

METHODS AND MATERIALS

We included 133 patients with prostate cancer that displayed either distant metastases (DM) or lymph node metastases alone (NM) and were treated between 2004 and 2019. All patients underwent computed tomography and a bone scan or 18F- or prostate-specific membrane antigen-targeted positron emission tomography. Patients received local external beam radiation therapy to the prostate to achieve local control (60-81.4 Gy to the prostate, and 45-50.4 Gy to pelvic lymph nodes), with either the 3D conformal (4-field box) or volumetric modulated arc therapy technique. A urologist prescribed additional therapy.

RESULTS

We included 51 patients with DM and 82 patients with NM. The mean follow-up was 42 months for all patients. The groups were similar in T stage, initial prostate-specific antigen, histology, androgen deprivation therapy, age, treatment techniques, and prescribed doses, but different in lymph node inclusion and follow-up times. In the NM and DM groups, the 5‑year biochemical recurrence-free rates were 52% and 24%, respectively (p < 0.0001); the 5‑year disease-specific survival rates were 92% and 61%, respectively (p = 0.001); and the 5‑year OS rates were 77% and 48%, respectively (p = 0.01). The groups had similar acute and late gastrointestinal and genitourinary side effects, except that late genitourinary side effects occurred significantly more frequently in the NM group (p = 0.01).

CONCLUSIONS

DM was associated with significantly worse outcomes than NM. The long-term survival of patients with metastatic prostate cancer was low.

Long-term Outcomes Following Radiation Therapy For Prostate Cancer Patients With Lymph Node Metastases at Diagnosis Treated With and Without Surgery

OBJECTIVES

To evaluate the long-term outcomes for prostate cancer (PCa) patients with lymph node involvement (LNI) treated with radiotherapy at the University of California San Francisco.

MATERIALS AND METHODS

All newly diagnosed PCa patients with LNI treated with radiotherapy as primary therapy or after surgery, each with and without hormonal therapy (HT) between 1988 and 2009 were included.Thirty-five patients (38%) were managed with external beam radiotherapy alone (eRT), 18 patients (20%) with radical prostatectomy (RP)+adjuvant radiotherapy, and 38 patients (42%) with RP+salvage radiotherapy. Overall 82% of the study sample received HT with similar proportions among radiation therapy (RT) subsets (P=0.83).

RESULTS

The median follow-up (FU) was 65, 42, and 86 months for patients treated with eRT, adjuvant radiotherapy, and salvage radiotherapy, respectively.The 10-year estimates from start of primary therapy for patients with LNI for overall survival (OS) was 78% (95% confidence interval [CI], 62%-88%) and for cause-specific survival was 89% (95% CI, 78%-95%). The 5-year estimates from the start of RT for biochemically no evidence of disease was 68% (95% CI, 56%-78%) and for disease-free survival was 67% (95% CI, 54%-77%). There was no difference in any of these outcomes among the 3 RT groups.Patients treated with HT were more likely to have a better 10-year OS (82% vs. 66%; log rank: P=0.001).Multivariate analysis indicated that only age and Gleason score were significant predictors for biochemically no evidence of disease and OS.

CONCLUSIONS

Patients diagnosed with PCa with LNI who were treated with RT with or without a prior surgery had relatively favorable long-term outcomes.

Nuclear KLLN expression associates with improved relapse-free survival for prostate carcinoma

Men with organ-confined prostate cancer (CaP) are often treated with radical prostatectomy. Despite similar postoperative characteristics, a significant proportion of men with an intermediate risk of progression experience prostate-specific antigen (PSA)-defined failure, while others have relapse-free survival (RFS). Additional prognostic markers are needed to predict the outcome of these patients. KLLN is a transcription factor that regulates the cell cycle and induces apoptosis in cancer cells. We have shown that KLLN is an androgen-regulated gene and that loss of KLLN expression in primary CaP is associated with high Gleason score. In this retrospective study, we evaluated KLLN expression in the high-grade malignancy components from 109 men with intermediate risk CaP. Patients with nuclear KLLN-negative tumors had significantly higher preoperative serum PSA levels (12.24±2.37 ng/ml) and larger tumor volumes (4.61±0.71 cm(3)) compared with nuclear KLLN-positive patients (8.35±2.45 ng/ml, P=0.03, and 2.66±0.51 cm(3), P<0.0001, respectively). None of the nuclear KLLN-positive tumors had capsular penetration, whereas 34% of nuclear KLLN-negative tumors (P=0.004) had capsular penetration. Maintaining KLLN expression in tumor nuclei, but not in cytoplasm or stroma, associated with improved RFS after surgery (P=0.002). Only 7% of patients with nuclear KLLN-positive tumors had tumor recurrence, while 60% of patients in the KLLN-negative group developed PSA-defined failure with median relapse time of 6.6 months (P=0.0003). Our data suggest that KLLN expression may be used as a prognostic marker to predict outcome for intermediate risk patients, which could provide useful information for postoperative management.

Evolving treatment paradigms for locally advanced and metastatic prostate cancer

While men with early stage prostate cancer typically enjoy long-term survival after definitive management, for those who present with locally advanced or metastatic disease, survival is compromised. Multimodality therapy can prolong survival in these patients, with state-of-the-art options including intensity-modulated radiation or brachytherapy in conjunction with androgen ablation, adjuvant androgen ablation and/or chemotherapy with radical retropubic prostatectomy. In addition, novel biological therapies are being explored to target the unique molecular changes in prostate cancer cells and their interactions with the microenvironment. With these advances the outlook will undoubtedly improve, even for patients presenting with advanced disease. Careful application of these emerging therapies to a select group of prostate cancer patients most likely to obtain benefit from them is the challenge for urologists, medical oncologists and radiation oncologists for the future.

Hypofractionated intensity-modulated arc therapy for lymph node metastasized prostate cancer: early late toxicity and 3-year clinical outcome

BACKGROUND AND PURPOSE

For patients with N1 prostate cancer (PCa) aggressive local therapies can be advocated. We evaluated clinical outcome, gastro-intestinal (GI) and genito-urinary (GU) toxicity after intensity modulated arc radiotherapy (IMAT)+androgen deprivation (AD) for N1 PCa.

MATERIAL AND METHODS

Eighty patients with T1-4N1M0 PCa were treated with IMAT and 2-3years of AD. A median dose of 69.3Gy (normalized isoeffective dose at 2Gy per fraction: 80Gy [α/β=3]) was prescribed in 25 fractions to the prostate. The pelvic lymph nodes received a minimal dose of 45Gy. A simultaneous integrated boost to 72Gy and 65Gy was delivered to the intraprostatic lesion and/or pathologically enlarged lymph nodes, respectively. GI and GU toxicity was scored using the RTOG/RILIT and RTOG-SOMA/LENT-CTC toxicity scoring system respectively. Three-year actuarial risk of grade 2 and 3/4 GI-GU toxicity and biochemical and clinical relapse free survival (bRFS and cRFS) were calculated with Kaplan-Meier statistics.

RESULTS

Median follow-up was 36months. Three-year actuarial risk for late grade 3 and 2 GI toxicity is 8% and 20%, respectively. Three-year actuarial risk for late grade 3-4 and 2 GU toxicity was 6% and 34%, respectively. Actuarial 3-year bRFS and cRFS was 81% and 89%, respectively. Actuarial 3-year bRFS and cRFS was, respectively 26% and 32% lower for patients with cN1 disease when compared to patients with cN0 disease.

CONCLUSION

IMAT for N1 PCa offers good clinical outcome with moderate toxicity. Patients with cN1 disease have poorer outcome.

A retrospective analysis of the prognosis of prostate cancer patients with lymph node involvement on MR lymphography: who might be cured

Background

The prognosis of prostate cancer patients with lymph node metastases so small they can only be visualized by new imaging techniques as MR lymphography (MRL) is unknown. The purpose of this study was to investigate the prognosis of prostate cancer patients with non-enlarged metastatic lymph nodes on MRL and to identify a subgroup of MRL-positive patients who might be candidates for curative treatment.

Methods

The charts of 138 prostate cancer patients without enlarged lymph nodes on CT, in whom a pre-treatment MRL was performed were reviewed. Endpoints were distant metastases-free survival and overall survival. Relation between the following factors and outcome were investigated: T-stage, PSA value at diagnosis, Gleason score, diameter (short axis and long axis) of the largest MRL-positive lymph node, number of MRL-positive lymph nodes, the presence of extra-pelvic nodal disease, and the extent of resection of the positive lymph nodes. Kaplan-Meier analysis was performed to estimate the survival functions.

Results

Of the 138 patients, 24 (17%) had a positive MRL. Patients with a short axis of the largest positive lymph node of ≤8 mm had a significantly better 5-year distant metastases-free (79% vs 16%) and overall survival (81% vs 36%) than patients with larger positive lymph nodes. This also accounted for patients with a largest long axis of ≤10 mm (71% vs 20% and 73% vs 40%, respectively). Outcome was also better in patients in whom all positive lymph nodes had been resected.

Conclusion

A selection of MRL-positive patients with a good prognosis could be identified, consisting of patients with small positive lymph nodes. In these patients, cure might be pursued.

Management of prostate cancer patients with lymph node involvement: a rapidly evolving paradigm

Although widespread PSA screening has inevitably led to increased diagnosis of lower risk prostate cancer, the number of patients with nodal involvement at baseline remains high (nearly 40% of high risk patients initially staged cN0). These rates probably do not reflect the true incidence of prostate cancer with lymph node involvement among patients selected for external beam radiotherapy (EBRT), as patients selected for surgery often have more favorable prognostic features. At many institutions, radical treatment directed only at the prostate is considered standard and patients known to have regional disease are often managed palliatively with androgen deprivation therapy (ADT) for presumed systemic disease. New imaging tools such as MR lymphangiography, choline-based PET imaging or combined SPECT/CT now allow surgeons and radiation oncologists to identify and target nodal metastasis and/or lymph nodes with a high risk of occult involvement. Recent advances in the field of surgery including the advent of extended nodal dissection and sentinel node procedures have suggested that cancer-specific survival might be improved for lymph-node positive patients with a low burden of nodal involvement when managed with aggressive interventions. These new imaging tools can provide radiation oncologists with maps to guide delivery of high dose conformal radiation to a target volume while minimizing radiation toxicity to non-target normal tissue. This review highlights advances in imaging and reports how they may help to define a new paradigm to manage node-positive prostate cancer patients with a curative-intent.

Robotic image-guided stereotactic radiotherapy, for isolated recurrent primary, lymph node or metastatic prostate cancer

PURPOSE

To evaluate the outcome of robotic CyberKnife (Accuray, Sunnyvale, CA)-based stereotactic radiotherapy (CBK-SRT) for isolated recurrent primary, lymph node, or metastatic prostate cancer.

METHODS AND MATERIALS

Between May 2007 and December 2009, 34 consecutive patients/38 lesions were treated (15 patients reirradiated for local recurrence [P], 4 patients reirradiated for anastomosis recurrence [A], 16 patients treated for single lymph node recurrence [LN], and 3 patients treated for single metastasis [M]). In all but 4 patients, [(11)C]choline positron emission tomography/computed tomography was performed. CBK-SRT consisted of reirradiation and first radiotherapy in 27 and 11 lesions, respectively. The median CBK-SRT dose was 30 Gy in 4.5 fractions (P, 30 Gy in 5 fractions; A, 30 Gy in 5 fractions; LN, 33 Gy in 3 fractions; and M, 36 Gy in 3 fractions). In 18 patients (21 lesions) androgen deprivation was added to CBK-SRT (median duration, 16.6 months).

RESULTS

The median follow-up was 16.9 months. Acute toxicity included urinary events (3 Grade 1, 2 Grade 2, and 2 Grade 3 events) and rectal events (1 Grade 1 event). Late toxicity included urinary events (3 Grade 1, 2 Grade 2, and 2 Grade 3 events) and rectal events (1 Grade 1 event and 1 Grade 2 event). Biochemical response was observed in 32 of 38 evaluable lesions. Prostate-specific antigen stabilization was seen for 4 lesions, and in 2 cases prostate-specific antigen progression was reported. The 30-month progression-free survival rate was 42.6%. Disease progression was observed for 14 lesions (5, 2, 5, and 2 in Groups P, A, LN, and M respectively). In only 3 cases, in-field progression was seen. At the time of analysis (May 2010), 19 patients are alive with no evidence of disease and 15 are alive with disease.

CONCLUSIONS

CyberKnife-based stereotactic radiotherapy is a feasible approach for isolated recurrent primary, lymph node, or metastatic prostate cancer, offering excellent in-field tumor control and a low toxicity profile. Further investigation is warranted to identify the patients who benefit most from this treatment modality. The optimal combination with androgen deprivation should also be defined.

Helical Tomotherapy with Simultaneous Integrated Boost for High-Risk and Lymph Node-Positive Prostate Cancer: Early Report on Acute and Late Toxicity

The use of whole pelvic radiotherapy (WPRT) for high-risk and lymph node-positive prostate cancer (PC) remains controversial. The purpose of this study was to evaluate the acute toxicity associated with helical tomotherapy in the treatment of high-risk and lymph node-positive prostate cancer. To do so, twenty-eight patients were treated to a dose of 54 Gy in daily fractions of 1.8 Gy to the pelvic lymph node area, while the prostate and the seminal vesicles received a simultaneous integrated boost (SIB) to a dose of 70.5 Gy. A SIB to a dose of 60 Gy was delivered to the involved lymph node region(s) in 8 patients with pelvic lymph node metastases. All patients received concurrent hormonal treatment. The incidence of grade 2 and 3 acute gastrointestinal (GI) toxicity was 7% and 0% respectively. Grade 2 and 3 acute genito-urinary (GU) side effects were observed in 14% and 4% of the patients respectively. No grade 4 side effects occurred. No increased toxicity was observed in the 8 lymph node-positive patients receiving a simultaneous pelvic nodal dose escalation. In conclusion, WPRT with a SIB to the prostate and seminal vesicles by helical tomotherapy resulted in a favourable toxicity profile. Pelvic nodal dose escalation in node-positive patients is feasible without increasing toxicity.

Biodistributions of 177Lu- and 111In-labeled 7E11 antibodies to prostate-specific membrane antigen in xenograft model of prostate cancer and potential use of 111In-7E11 as a pre-therapeutic agent for 177Lu-7E11 radioimmunotherapy

INTRODUCTION

Prostate-specific membrane antigen is a transmembrane glycoprotein highly expressed in many prostate cancers and can be targeted with radiolabeled antibodies for diagnosis and treatment of this disease. To serve as a radioimmunotherapeutic agent, a kinetically inert conjugate is desired to maximize tumor uptake and tumor radiation dose with minimal nonspecific exposure to bone marrow and other major organs.

MATERIALS AND METHODS

In this study, we assessed the pharmacokinetics and biodistribution of the 7E11 monoclonal antibody (MAb) radiolabeled with the lutetium-177 ((177)Lu)-tetraazacyclododecanetetraacetic acid conjugate system ((177)Lu-7E11) versus those of the 7E11 MAb radiolabeled with the indium-111 ((111)In)/glycyl-tyrosyl-(N,-diethylenetriaminepentaacetic acid)/lysine hydrochloride conjugate system ((111)In-7E11, also known as ProstaScint) to determine the feasibility of using (111)In-7E11 as a pre-therapeutic agent for (177)Lu-7E11 radioimmunotherapy. Pharmacokinetic and biodistribution studies of (177)Lu-7E11 in lymph node cancer of the prostate (LNCaP) xenograft mice were performed at 2, 8, 12, 24, 72, and 168 h after radiopharmaceutical administration. For (111)In-7E11, pharmacokinetic and biodistribution studies were performed at 8, 24, and 72 h. Parallel studies of (177)Lu-7E11 in non-tumor-bearing mice at 8, 24, and 72 h post-injection served as controls. Gamma scintigraphy was performed, followed by autoradiography and tissue counting, to demonstrate and quantify the distributions of radioconjugated MAb in the tumor and normal tissues.

RESULTS AND DISCUSSION

Both (177)Lu- and (111)In-7E11 conjugates demonstrated an early blood pool phase in which uptake was dominated by the blood, lung, spleen and liver, followed by uptake and retention of the radiolabeled antibody in the tumor which was most prominent at 24 h. Total accumulation of radioconjugated MAb in tumor at 24 h was greater in the case of (177)Lu-7E11 in comparison to that of (111)In-7E11. Continued accumulation in tumor was observed for the entire time course studied for both (177)Lu-7E11 and (111)In-7E11. The liver was the only major organ demonstrating a significant difference in accumulation between the two conjugates. In conclusion, pharmacokinetic and biodistribution studies of (177)Lu-7E11 in LNCaP xenograft mouse models support its potential application as a radioimmunotherapeutic agent targeting prostate cancer, and the distribution and tumor uptake of (111)In-7E11 appear to be similar to those of (177)Lu-7E11, supporting its use as a pre-therapeutic tool to assess the potential accumulation of (177)Lu-7E11 radioimmunotherapeutic at sites of prostate cancer. However, the different accumulation patterns of the (111)In and (177)Lu immunoconjugates in liver will likely prevent the use of (111)In-7E11 as a true dosimetry tool for (177)Lu-7E11 radioimmunotherapy.

Utility of a new bolus-injectable nanoparticle for clinical cancer staging

BACKGROUND

In this study, we report on the use of a new, bolus-injectable, carboxymethyl dextran-based magnetic nanoparticle (MNP), ferumoxytol, to improve detection in loco-regional lymph nodes by magnetic resonance imaging (MRI).

METHODS

This preliminary study was performed as a prospective, single-center, open label pilot study to determine the magnitude of nodal MRI signal changes and to determine the optimal time points for imaging following intravenous (IV) bolus injection of the MNP. The study group consisted of 10 patients, all of whom were diagnosed with prostate cancer before any systemic therapy.

RESULTS

All 10 patients had lymph nodes evaluated by histopathology. Of the evaluated 26 lymph nodes, 20 were benign and 6 were malignant. The mean short-axis diameter of benign lymph nodes was 6 mm and the mean short-axis diameter of malignant lymph nodes was 7 mm. Following IV administration, there was a significant change in mean signal-to-noise ratio (SNR) of benign lymph nodes (P < .0001) whereas there was little change in the mean SNR of malignant nodes (P = .1624). No adverse events were encountered.

CONCLUSION

Ferumoxytol is safe and, at the appropriate circulation interval, modulates nodal signal intensity, allowing for identification of malignant nodal involvement by MRI.

The detection rate of [11C]choline-PET/CT depends on the serum PSA-value in patients with biochemical recurrence of prostate cancer

PURPOSE

An increase of the serum PSA-level is a sensitive in vitro marker for recurrent prostate cancer. However, it remains difficult to differentiate between local, regional or distant recurrent disease. The aim of this study was to assess the relationship between the detection rate of [(11)C]Choline-PET/CT and the serum PSA-level in patients with a biochemical recurrence of prostate cancer with the view towards localisation of recurrent disease.

METHODS

Sixty-three patients (mean age, 68.8 +/- 6.9; range, 45-83 years) with biochemical recurrence after primary therapy for prostate cancer were included in the analysis. Mean PSA-levels were 5.9 +/- 9.7 ng/ml (range, 0.2-39 ng/ml; median, 2.15). Of the 63 patients, 17 were under anti-androgen therapy at the time of [(11)C]Choline PET/CT. Patients underwent a [(11)C]Choline-PET/CT study after injection of 656 +/- 119 MBq [(11)C]Choline on a Sensation 16 Biograph PET/CT scanner.

RESULTS

Of the 63 patients, 35 (56%) showed a pathological [(11)C]Choline uptake. The detection rate of [(11)C]Choline-PET/CT showed a relationship with the serum PSA-level: The detection rate was 36% for a PSA-value <1 ng/ml, 43% for a PSA-value 1-<2 ng/ml, 62% for a PSA-value 2-<3 ng/ml and 73% for a PSA-value >or=3 ng/ml. Anti-androgen therapy did not show a significant effect on the detection rate of [(11)C]Choline-PET/CT (p = 0.374).

CONCLUSION

As an important result our study shows that even for PSA-values <1.0 ng/ml the detection efficiency of [(11)C]Choline-PET/CT is 36%. Furthermore, the detection rate of [(11)C]Choline-PET/CT shows a positive relationship with serum PSA-levels in patients with biochemical recurrence of prostate cancer after primary therapy. Therefore, in these patients, [(11)C]Choline PET/CT allows not only to diagnose but also to localise recurrent disease with implications on disease management (localised vs systemic therapy).

Evidence-based radiation oncology: Definitive, adjuvant and salvage radiotherapy for non-metastatic prostate cancer

The standard treatment options based on the risk category (stage, Gleason score, PSA) for localized prostate cancer include surgery, radiotherapy and watchful waiting. The literature does not provide clear-cut evidence for the superiority of surgery over radiotherapy, whereas both approaches differ in their side effects. The definitive external beam irradiation is frequently employed in stage T1b-T1c, T2 and T3 tumors. There is a pretty strong evidence that intermediate- and high-risk patients benefit from dose escalation. The latter requires reduction of the irradiated normal tissue (using 3-dimensional conformal approach, intensity modulated radiotherapy, image-guided radiotherapy, etc.). Recent data suggest that prostate cancer may benefit from hypofractionation due to relatively low alpha/beta ratio; these findings warrant confirmation though. The role of whole pelvis irradiation is still controversial. Numerous randomized trials demonstrated a clinical benefit in terms of biochemical control, local and distant control, and overall survival from the addition of androgen suppression to external beam radiotherapy in intermediate- and high-risk patients. These studies typically included locally advanced (T3-T4) and poor-prognosis (Gleason score >7 and/or PSA >20 ng/mL) tumors and employed neoadjuvant/concomitant/adjuvant androgen suppression rather than only adjuvant setting. The ongoing trials will hopefully further define the role of endocrine treatment in more favorable risk patients and in the setting of the dose escalated radiotherapy. Brachytherapy (BRT) with permanent implants may be offered to low-risk patients (cT1-T2a, Gleason score <7, or 3+4, PSA <or=10 ng/mL), with prostate volume of <or=50 ml, no previous transurethral prostate resection and a good urinary function. Some recent data suggest a benefit from combining external beam irradiation and BRT for intermediate-risk patients. EBRT after radical prostatectomy improves disease-free survival and biochemical and local control rates in patients with positive surgical margins or pT3 tumors. Salvage radiotherapy may be considered at the time of biochemical failure in previously non-irradiated patients.

Long-term outcome for lymph node-positive prostate cancer

Although the number of men with lymph node-positive prostate cancer has declined, it is still significant and the challenge remains on how best to treat these patients. Only long-term follow-up can give a true indication of the outcome in prostate cancer. We evaluated our experience in treating lymph node-positive prostate cancer with a median follow-up of 10.2 years. The overall 5-year survival was 78% and the 10-year survival was 56%. Length of tumor control depends on the type of treatment given. Adding androgen ablation improves the duration of control dramatically, although optimal timing is still uncertain.