Salvage therapy of small volume prostate cancer nodal failures: a review of the literature

Radiotherapy in nodal oligorecurrent prostate cancer

Objective

The current article encompasses a literature review and recommendations for radiotherapy in nodal oligorecurrent prostate cancer.

Materials and methods

A literature review focused on studies comparing metastasis-directed stereotactic ablative radiotherapy (SABR) vs. external elective nodal radiotherapy (ENRT) and studies analyzing recurrence patterns after local nodal treatment was performed. The DEGRO Prostate Cancer Expert Panel discussed the results and developed treatment recommendations.

Results

Metastasis-directed radiotherapy results in high local control (often > 90% within a follow-up of 1–2 years) and can be used to improve progression-free survival or defer androgen deprivation therapy (ADT) according to prospective randomized phase II data. Distant progression after involved-node SABR only occurs within a few months in the majority of patients. ENRT improves metastases-free survival rates with increased toxicity in comparison to SABR according to retrospective comparative studies. The majority of nodal recurrences after initial local treatment of pelvic nodal metastasis are detected within the true pelvis and common iliac vessels.

Conclusion

ENRT with or without a boost should be preferred to SABR in pelvic nodal recurrences. In oligometastatic prostate cancer with distant (extrapelvic) nodal recurrences, SABR alone can be performed in selected cases. Application of additional systemic treatments should be based on current guidelines, with ADT as first-line treatment for hormone-sensitive prostate cancer. Only in carefully selected patients can radiotherapy be initially used without additional ADT outside of the current standard recommendations. Results of (randomized) prospective studies are needed for definitive recommendations.

Phase II trial of high dose stereotactic body radiation therapy for lymph node oligometastases

Lymph nodes are common sites of oligometastases for several primaries. Stereotactic body radiation therapy (SBRT) represents an effective treatment but no consensus exists regarding dose and fractionation. Aim of this trial was to evaluate safety and efficacy of high-dose SBRT. We included patients with 1 to 3 lymph node metastases. Primary end-point was safety, while secondary end-points were in-field local control (LC), out-field lymph nodal progression free survival (LPFS), distant metastasis free survival (DMFS), progression free survival (PFS) and overall survival (OS). 64 lesions in 52 patients were treated from 2015 to 2019. Most common primary tumor was genitourinary cancer (75%), in particular prostate cancer (65.4%). With a median follow-up of 24.4 months (range 3-49), treatment was very well tolerated, with only 4 (7.7%) patients reporting acute side effects, all classified as grade 1, in the form of pain, fatigue, nocturia and dysuria. No toxicity ≥ grade 2 were reported. Rates of LC at 1, 2 and 3 years were 97.9%, 82.1% and 82.1%. Male sex (HR 0.12, p value 0.014) was associated with improved LC. LPFS at 1, 2 and 3 years were 69.6%, 49.6% and 46.1%, respectively, and DMFS was 81.74%, 67.5% and 58.5%, respectively. Presence of lesions in other organs was correlated with inferior DMFS (HR 3.82, p = 0.042). PFS at 1, 2 and 3 years were 67.4%, 42.4% and 31.86%, respectively. OS at 1, 2 and 3 years were 97.3%, 94.2%, 84%, respectively and significantly correlated with in-field recurrence (HR 8.72, p = 0.000). Our prospective trial confirms safety and efficacy of SBRT in the management of lymph node metastases. Registered Clinical trial NCT02570399.

Long-term clinical outcomes of salvage pelvic radiation therapy for oligo-recurrent pelvic lymph nodes after definitive external-beam radiation therapy for non-metastatic prostate cancer

Although salvage external-beam radiation therapy (EBRT) is an attractive treatment option for pelvic lymph nodal recurrence (PeNR) in patients with prostate cancer (PCa), limited data are available regarding its long-term efficacy. This study examined the long-term clinical outcomes of patients who underwent salvage pelvic radiation therapy (sPRT) for oligo-recurrent pelvic lymph nodes after definitive EBRT for non-metastatic PCa. Patients who developed PeNR after definitive EBRT and were subsequently treated with sPRT at our institution between November 2007 and December 2015 were retrospectively analyzed. The prescribed dose was 45-50.4 Gy (1.8-2 Gy per fraction) to the upper pelvis, with up to 54-66 Gy (1.8-2 Gy per fraction) for recurrent nodes. Long-term hormonal therapy was used as neoadjuvant and/or adjuvant therapy. The study population consisted of 12 consecutive patients with PeNR after definitive EBRT (median age: 73 years). The median follow-up period was 58.9 months. The 5-year overall survival, PCa-specific survival, biochemical failure-free, clinical failure-free, and castration-resistant PCa-free rates were 82.5, 100.0, 62.3, 81.8, and 81.8%, respectively. No grade 2 or higher sPRT-related late toxicities occurred. In conclusion, more than half of the study patients treated with sPRT had a long-term disease-free status with acceptable morbidities. Moreover, most of the patients maintained hormonal sensitivity. Therefore, this approach may be a promising treatment method for oligo-recurrent pelvic lymph nodes.

Can thoracic nodes oligometastases be safely treated with image guided hypofractionated radiation therapy?

OBJECTIVE

To evaluate safety and efficacy of image guided-hypofractionated radiation therapy (IG-HRT) in patients with thoracic nodes oligometastases.

METHODS

The present study is a multicenter analysis. Oligometastatic patients, affected by a maximum of five active lesions in three or less different organs, treated with IG-HRT to thoracic nodes metastases between 2012 and 2017 were included in the analysis. Primary end point was local control (LC), secondary end points were overall survival (OS), progression-free survival, acute and late toxicity. Univariate and multivariate analysis were performed to identify possible prognostic factors for the survival end points.

RESULTS

76 patients were included in the analysis. Different RT dose and fractionation schedules were prescribed according to site, number, size of the lymph node(s) and to respect dose constraints for relevant organs at risk. Median biologically effective dose delivered was 75 Gy (interquartile range: 59-86 Gy). Treatment was optimal; one G1 acute toxicity and seven G1 late toxicities of any grade were recorded. Median follow-up time was 23.16 months. 16 patients (21.05%) had a local progression, while 52 patients progressed in distant sites (68.42 %).Median local relapse free survival was not reached, LC at 6, 12 and 24 months was 96.05% [confidence interval (CI) 88.26-98.71%], 86.68% (CI 75.86-92.87) and 68.21% (CI 51.89-80.00%), respectively. Median OS was 28.3 months (interquartile range 16.1-47.2). Median progression-freesurvival was 9.2 months (interquartile range 4.1-17.93).At multivariate analysis, RT dose, colorectal histology, systemic therapies were correlated with LC. Performance status and the presence of metastatic sites other than the thoracic nodes were correlated with OS. Local response was a predictor of OS.

CONCLUSION

IG-HRT for thoracic nodes was safe and feasible. Higher RT doses were correlated to better LC and should be taken in consideration at least in patients with isolated nodal metastases and colorectal histology.

ADVANCES IN KNOWLEDGE

Radiotherapy is safe and effective treatment for thoracic nodes metastases, higher radiotherapy doses are correlated to better LC. Oligometastatic patients can receive IG-HRT also for thoracic nodes metastases.

[Radiotherapy of oligometastatic pelvic node relapses in patients with prostate cancer]

The Oligopelvis 2 studies is based on the assumption that salvage pelvic radiotherapy may prolong the interval between the first and the second intermittent hormone therapy sequence in pelvic lymph node oligometastatic prostate cancer. This phase 3 study will compare intermittent hormone therapy (standard arm) alone or combined with salvage pelvic radiotherapy (experimental arm).

PET imaging for lymph node dissection in prostate cancer

The detection of neoplastic lymph nodal involvement in prostate cancer (PCa) patients has relevant therapeutic and prognostic significance, both in the clinical settings of primary staging and restaging. Lymph nodal dissection (LND) currently represents the gold standard for evaluating the presence of lymph nodal involvement. However, this procedure is invasive, associated with morbidity, and may fail in detecting all potential lymph nodal metastatic regions. Currently the criteria for lymph nodal detection using conventional imaging techniques mainly rely on morphological assessment with unsatisfactory diagnostic accuracy. Positron emission tomography (PET) represents a helpful imaging technique for a proper staging of lymph nodal status. The most investigated PET radiotracer is choline, although many others have been explored as guide for both primary and salvage LND, such as fluorodeoxyglucose, acetate, fluorocyclobutanecarboxylic acid and prostate-specific membrane antigen. In the present review, a comprehensive literature review addressing the role of PET for LND in PCa patients is reported, with the use of the above-mentioned radiotracers.

PET/CT and MRI directed extended salvage radiotherapy in recurrent prostate cancer with lymph node metastases

PURPOSE

PET/CT directed extended salvage radiotherapy (esRT) of involved lymph-node (LN) regions may be a salvage strategy for patients with nodal recurrent prostate cancer (PCa) after primary therapy or after previous prostate fossa salvage RT. The aim of the study was to determine the time until prostate-specific antigen (PSA) progression, pattern of failure and toxicity after esRT.

MATERIAL AND METHODS

25 patients with nodal or nodal+local recurrent PCa confirmed by Choline-PET/CT and Magnetic Resonance Imaging (MRI) were treated with esRT at the sites of recurrence. Acute and late toxicity was recorded. In case of subsequent PSA progression, imaging was performed to confirm next relapse. Mean follow-up was 2.9 years.

RESULTS

According to Choline-PET/CT and MRI findings, 84% (21/25) of esRT were treatment of pelvic only, 12% (3/25) of retroperitoneal only and 4% (1/25) of both pelvic and retroperitoneal regions. 40% (10/25) received concomitant irradiation of the prostatic fossa (after primary radical prostatectomy). Median time to PSA progression of the whole cohort was 19.6 months. Median time to PSA progression for patients with 1-2 PET-positive LN (n=15) was 34.9 months versus median 12.7 months for patients with PET-positive LN≥3 (n=10), p-value: 0.0476. Acute and late toxicity was mild to moderate, no grade-3 adverse events were observed.

CONCLUSION

PET/CT and MRI directed esRT of nodal recurrent PCa with or without local recurrence is feasible with low acute and late toxicity. Patients with only one or two PET-positive LN treated by esRT achieved prolonged complete biochemical remission.

CyberKnife Stereotactic Ablative Radiotherapy as an Option of Treatment for Patients With Prostate Cancer Having Oligometastatic Lymph Nodes

The aim of this study was to evaluate the effectiveness of CyberKnife-based stereotactic ablative radiotherapy on prostate cancer lymph node metastases. Our material consisted of 18 patients with 31 metastatic lymph nodes irradiated between 2011 and 2014 using CyberKnife-based stereotactic ablative radiotherapy. Patients were irradiated using fraction dose varied from 6 to 15 Gy (median 10), to the total dose of 24 to 45 Gy (median 30). Irradiated lymph node size varied from 0.4 to 4.0 cm. In all, 9 patients had single lymph node metastasis and 9 patients had metastases of 2 to 4 lymph nodes. Prostate-specific antigen concentration before radiotherapy varied from 0.01 to 15.58 (mean 6.97; median 4.66). All patients at the time of radiotherapy and follow-up received androgen deprivation therapy. Mann-Whitney U, Kaplan-Meier method, and log-rank tests were used in statistical analysis. We obtained the following results: after CyberKnife stereotactic ablative radiotherapy, prostate-specific antigen concentration dropped in majority of cases and during the last control varied from 0.00 to 258.00 (median 2.5), and was lower in patients without dissemination to other organs ( P = .01). Complete regression was found in 12 lesions, stable disease in 13, and progression in 4. In 7 patients, the dissemination to other organs occurred. Our results allow us to conclude that CyberKnife stereotactic ablative radiotherapy of prostate cancer lymph node oligometastases gives good local control and relatively good prostate-specific antigen response.

Clinical variability and molecular heterogeneity in prostate cancer

Prostate cancer is a clinically heterogeneous disease, with some men having indolent disease that can safely be observed, while others have aggressive, lethal disease. Over the past decade, researchers have begun to unravel some of the genomic heterogeneity that contributes to these varying clinical phenotypes. Distinct molecular sub-classes of prostate cancer have been identified, and the uniqueness of these sub-classes has been leveraged to predict clinical outcomes, design novel biomarkers for prostate cancer diagnosis, and develop novel therapeutics. Recent work has also elucidated the temporal and spatial heterogeneity of prostate cancer, helping us understand disease pathogenesis, response to therapy, and progression. New genomic techniques have provided us with a window into the remarkable clinical and genomic heterogeneity of prostate cancer, and this new perspective will increasingly impact patient care.

OLIGOPELVIS - GETUG P07: a multicentre phase II trial of combined salvage radiotherapy and hormone therapy in oligometastatic pelvic node relapses of prostate cancer

Background

Metastatic prostate cancer remains a common cause of death in Europe, and improvements in management of the disease are urgently needed. The advent of positron-emission tomography (PET) imaging enhanced with fluorocholine has led to the identification of a new sub-group of metastatic prostate cancer patients: those with so-called oligometastatic disease. Presenting with a low burden of metastatic disease (≤5 lesions), this new sub-group lies between true metastatic prostate cancer patients for whom androgen- deprivation therapy (ADT) is the mainstay of treatment, and patients with a rising PSA, but no visible lesion on conventional imaging, in whom intermittent ADT has been shown to be no less effective than continuous ADT. One might conclude that intermittent ADT would also be the standard of care for oligometastatic prostate cancer patients, but radical strategies such as extensive lymphadenectomy or high-dose radiotherapy have been suggested as another means to delay the need for ADT, and increase its effectiveness once initiated. This study will explore the role of salvage pelvic image-guided intensity-modulated radiation therapy (IMRT) combined with ADT administered for 6 months in pelvic oligometastatic patients in prolonging the failure-free interval between two consecutive ADT courses, or even to cure selected patients with limited metastatic burden.

Methods/Design

We plan to assess the two year outcome in oligometastatic prostate cancer patients (1–5 pelvic oligometastases) treated concomitantly with high-dose IMRT (54 Gy, 30 fractions to the pelvis and 66 Gy, 30 fractions to the lymph nodes) and ADT for six months.

Discussion

This multicenter prospective phase II study will yield new data regarding the safety and efficacy of high-dose radiotherapy combined with ADT and will provide a basis for a larger phase III study to examine the role of radiotherapy in this population currently treated only with hormone therapy.

Trial registration

NCT02274779, date of registration: 23/10/14

Spanish Society of Radiation Oncology clinical guidelines for stereotactic body radiation therapy in lymph node oligometastases

Data in the literature support the existence of a state of limited metastases or oligometastases. Favorable outcomes have been observed in selected patients with such oligometastases that are treated with local ablative therapies, which include surgical extirpation, stereotactic body radiation therapy (SBRT), and radiofrequency ablation. The role of SBRT in the setting of lymph node oligometastases is still emerging but the early results for local control are promising. However, the biggest challenge is to identify patients who will benefit from treatment of their oligometastatic disease with local aggressive therapy. Patients are initially categorized based upon examination of the initial biopsy, location, stage, and previous treatments received. Appropriate patient management with SBRT requires an understanding of several clinicopathological features that help to identify several subsets of patients with more responsive tumors and a good tolerance to SBRT. In an effort to incorporate the most recent evidence, here the Spanish Society of Radiation Oncology presents guidelines for using SBRT in lymph node oligometastases.

Could machine learning improve the prediction of pelvic nodal status of prostate cancer patients? Preliminary results of a pilot study

We tested and compared performances of Roach formula, Partin tables and of three Machine Learning (ML) based algorithms based on decision trees in identifying N+ prostate cancer (PC). 1,555 cN0 and 50 cN+ PC were analyzed. Results were also verified on an independent population of 204 operated cN0 patients, with a known pN status (187 pN0, 17 pN1 patients). ML performed better, also when tested on the surgical population, with accuracy, specificity, and sensitivity ranging between 48-86%, 35-91%, and 17-79%, respectively. ML potentially allows better prediction of the nodal status of PC, potentially allowing a better tailoring of pelvic irradiation.

Is Stereotactic Body Radiotherapy (SBRT) in lymph node oligometastatic patients feasible and effective?

OBJECTIVES

To review the available data about stereotactic body-radiotherapy (SBRT) for oligometastatic lymph node cancer recurrence.

METHODS

The inclusion criteria for this study were as follows: Medline search for the (1) English language (2) full paper (abstracts were excluded) on (3) adult oligometastatic solid cancer recurrence limited to lymph node that underwent SBRT (4) outcome data available and (5) published up to the 30th April 2014.

RESULTS

38 papers fulfilling the inclusion criteria have been found: 7 review articles and 31 patient series (20 and 11 retrospective and prospective studies, respectively) including between 1 and 69 patients (636 lymph nodes). Twelve articles reported only lymph node SBRT while in 19 - all types of SBRT including lymph node SBRT were presented. Two-year local control, 4-year progression free survival and overall survival was of up to 100%, 30% and 50%, respectively. The progression was mainly out-field (10-30% of patients had a recurrence in another lymph node/nodes). The toxicity was low with mainly mild acute events and single grade 3-4 late events. When compared to SBRT for any oligometastatic cancer, SBRT for lymph node recurrence carried better prognosis and showed lower toxicity.

CONCLUSIONS

SBRT is a feasible approach for oligometastatic lymph node recurrence, offering excellent in-field tumor control with low toxicity profile. The potential abscopal effect has been hypothesized as a basis of these findings. Future studies are warranted to identify the patients that benefit most from this treatment. The optimal combination with systemic treatment should also be defined.

Toxicity and quality of life after choline-PET/CT directed salvage lymph node dissection and adjuvant radiotherapy in nodal recurrent prostate cancer

BACKGROUND

In a previous study we demonstrated that, based on 11C/18 F-choline positron emission tomography-computerized-tomography as a diagnostic tool, salvage lymph node dissection (LND) plus adjuvant radiotherapy (ART) is feasible for treatment of pelvic/retroperitoneal nodal recurrence of prostate cancer (PCa). However, the toxicity of this combined treatment strategy has not been systematically investigated before. The aim of the current study was to evaluate the acute and late toxicity and quality of life of ART after LND in pelvic/retroperitoneal nodal recurrent PCa.

MATERIAL AND METHODS

43 patients with nodal recurrent PCa were treated with 46 LND followed by ART (mean 49.6 Gy total dose) at the sites of nodal recurrence. Toxicity of ART was analysed by physically examination (31/43, 72.1%), by requesting 15 frequent items of adverse events from the Common-Terminology-Criteria for Adverse Events Version 4.0-catalogue and by review of medical records. QLQ-C30 (EORTC quality of life assessment) and PR25 (prostate cancer module) questionnaires were used to investigate quality of life. Toxicity was evaluated before starting of ART, during ART (acute toxicity), after ART (mean 2.3 months) and at end of follow up (mean 3.2 years after end of ART) reflecting late toxicity.

RESULTS

71.7% (33/46) of 46 ART were treatment of pelvic, 10.9% (5/46) of retroperitoneal only and 28.3% (13/46) of pelvic and retroperitoneal regions. Overall 52 symptoms representing toxicities were observed before ART, 107 during ART, 88 after end of ART and 52 at latest follow up. Leading toxicities during ART were diarrhoea (19%, 20/107), urinary incontinence (16%, 17/107) and fatigue (16%, 17/107). The spectrum of late toxicities was almost equal to those before beginning of ART. No grade 3 adverse events or chronic lymphedema at extremities were observed. We observed no clear correlation between localisation of treated regions, technique of ART and frequency or severity of toxicities. Mean quality of life at final evaluation was 74%.

CONCLUSION

ART after extended LND in PCa relapse is justifiable with respect to adverse effects and toxicity. The side effects were circumscribed and well tolerated. The spectrum of adverse events at latest follow up was almost equal to those before start of ART.

Long-term outcomes of salvage lymph node dissection for clinically recurrent prostate cancer: results of a single-institution series with a minimum follow-up of 5 years

BACKGROUND

Prostate cancer (PCa) patients with lymph node recurrence after radical prostatectomy (RP) are usually managed with androgen-deprivation therapy. Despite the absence of prospective randomized studies, salvage lymph node dissection (LND) has been proposed as an alternative treatment option.

OBJECTIVE

To examine long-term outcomes of salvage LND in patients with nodal recurrent PCa documented by 11C-choline positron emission tomography/computed tomography (PET/CT) scan.

DESIGN, SETTING, AND PARTICIPANTS

Overall, 59 patients affected by biochemical recurrence (BCR) with 11C-choline PET/CT scan with pathologic activity treated between 2002 and 2008 were included.

INTERVENTION

Pelvic and/or retroperitoneal salvage LND.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSES

Biochemical response (BR) was defined as prostate-specific antigen (PSA) <0.2 ng/ml at 40 d after surgery. BCR for those who achieved BR was defined as a PSA >0.2 ng/ml. Clinical recurrence (CR) was defined as a positive PET/CT scan after salvage LND in the presence of a rising PSA. Kaplan-Meier curves assessed time to BCR, CR, and cancer-specific mortality (CSM). Cox regression analyses were fitted to assess predictors of CR.

RESULTS AND LIMITATIONS

Median follow-up after salvage LND was 81.1 mo. Overall, 35 patients (59.3%) achieved BR. The 8-yr BCR-free survival rate in patients with complete BR was 23%. Overall, the 8-yr CR- and CSM-free survival rates were 38% and 81%, respectively. In multivariable analyses evaluating preoperative variables, PSA at salvage LND represented the only predictor of CR (p=0.03). When postoperative variables were considered, BR and the presence of retroperitoneal lymph node metastases were significantly associated with the risk of CR (all p ≤ 0.04). Our study is limited by the lack of a control group.

CONCLUSIONS

Salvage LND may represent a therapeutic option for patients with BCR after RP and nodal pathologic uptake at 11C-choline PET/CT scan. Although most patients progressed to BCR after salvage LND, roughly 40% of them experienced CR-free survival.

PATIENT SUMMARY

Salvage lymph node dissection may represent a therapeutic option for selected patients with nodal recurrence after radical prostatectomy. Roughly 40% of men did not show any further clinical recurrence at long-term follow-up after surgery.