Long-term impact of positive surgical margins on biochemical recurrence after radical prostatectomy: ten years of follow-up

Clinical outcomes for men with positive surgical margins after radical prostatectomy-results from the South Australian Prostate Cancer Clinical Outcomes Collaborative community-based registry

Objective

Positive surgical margins (PSMs) after radical prostatectomy (RP) indicate failure of surgery to completely clear cancer. PSMs confer an increased risk of biochemical recurrence (BCR), but how more robust outcomes are affected is unclear. This study investigated factors associated with PSMs following RP and determined their impact on clinical outcomes (BCR, second treatment [radiotherapy and/or androgen deprivation therapy], and prostate cancer-specific mortality [PCSM]).

Methods

The study cohort included men diagnosed with prostate cancer (pT2-3b/N0/M0) between January 1998 and June 2016 who underwent RP from the South Australian Prostate Cancer Clinical Outcomes Collaborative database. Factors associated with risk of PSMs were identified using Poisson regression. The impact of PSMs on clinical outcomes (BCR, second treatment, and PCSM) was assessed using competing risk regression.

Results

Of the 2827 eligible participants, 28% had PSMs-10% apical, 6% bladder neck, 17% posterolateral, and 5% at multiple locations. Median follow-up was 9.6 years with 81 deaths from prostate cancer recorded. Likelihood of PSM increased with higher pathological grade and pathological tumor stage, and greater tumour volume, but decreased with increasing surgeon volume (odds ratio [OR]: 0.93; 95% confidence interval [CI]: 0.88-0.98, per 100 previous prostatectomies). PSMs were associated with increased risk of BCR (adjusted sub-distribution hazard ratio [sHR] 2.5; 95% CI 2.1-3.1) and second treatment (sHR 2.9; 95% CI 2.4-3.5). Risk of BCR was increased similarly for each PSM location, but was higher for multiple margin sites. We found no association between PSMs and PCSM.

Conclusion

Our findings support previous research suggesting that PSMs are not independently associated with PCSM despite strong association with BCR. Reducing PSM rates remains an important objective, given the higher likelihood of secondary treatment with associated comorbidities.

Risk of severe late toxicity after radiotherapy following radical prostatectomy - a nationwide study

BACKGROUND

Severe side-effects are rare but may occur years after radiation therapy following radical prostatectomy. We sought to estimate the long-term risks of severe late toxicities in an unselected, nationwide, cohort.

METHODS

The study population comprised all men undergoing radical prostatectomy between 1997-2016 in the Prostate Cancer database Sweden (PCBaSe) (n=40,962). By (1:2) matching, two cohorts were created: 2789 men exposed to postoperative radiation and 5578 nonexposed men with comparable age, comorbidities and year of surgery. Cumulative incidences and rate ratios were calculated for the following outcomes: symptoms and interventions of the urinary or intestinal tract demanding inpatient care, secondary malignancies and non-prostate cancer mortality.

RESULTS

The largest differences were seen for late toxicities affecting the urinary tract. The 10-year cumulative incidences among those exposed to postoperative radiation versus the surgery only group were: 17.8% versus 10.5% for procedures of the urinary tract (difference 7.3%, 95% confidence interval [CI] 4.4 to 10.3; relative risk [RR] 1.74, 95% CI 1.47 to 2.05); 6.0% versus 1.2% for hematuria (difference 4.8%, 95% CI 3.1 to 6.5; RR 6.50 95% CI 4.31 to 10.10); and 2.4% versus 1.1% for bladder cancer (difference 1.4%, 95% CI 0.4 to 2.3; RR 2.71 95% CI 1.72 to 4.33). The groups were similar regarding intestinal toxicity, other secondary malignancies, and non-prostate cancer mortality. Adjustments for preoperative tumor risk factors did not importantly affect the rate ratios.

CONCLUSION

Severe late toxicity after postoperative radiation following radical prostatectomy predominately affects the bladder and can appear many years after radiotherapy.

Robot-Assisted Electrical Impedance Scanning system for 2D Electrical Impedance Tomography tissue inspection

The electrical impedance tomography (EIT) technology is an important medical imaging approach to show the electrical characteristics and the homogeneity of a tissue region noninvasively. Recently, this technology has been introduced to the Robot Assisted Minimally Invasive Surgery (RAMIS) for assisting the detection of surgical margin with relevant clinical benefits. Nevertheless, most EIT technologies are based on a fixed multiple-electrodes probe which limits the sensing flexibility and capability significantly. In this study, we present a method for acquiring the EIT measurements during a RAMIS procedure using two already existing robotic forceps as electrodes. The robot controls the forceps tips to a series of predefined positions for injecting excitation current and measuring electric potentials. Given the relative positions of electrodes and the measured electric potentials, the spatial distribution of electrical conductivity in a section view can be reconstructed. Realistic experiments are designed and conducted to simulate two tasks: subsurface abnormal tissue detection and surgical margin localization. According to the reconstructed images, the system is demonstrated to display the location of the abnormal tissue and the contrast of the tissues' conductivity with an accuracy suitable for clinical applications.

[Impact of positive surgical margins on prostate cancer prognosis]

OBJECTIVE

To examine the impact of positive surgical margins (PSM) after radical prostatectomy (RP) for prostate cancer on oncological results.

PATIENTS AND METHODS

We performed a study where all patients who underwent radical prostatectomy between January 2004 and December 2018 for prostate cancer were included. The preoperative, postoperative data and the carcinological results collected were analyzed. Data were analysed using Kaplan-Meier survival analysis and proportional hazards models.

RESULTS

A total of 319 patients with a median age of 65 years (IQR : 62-69) were included. The median follow-up was 43.6 months (IQR: 19.4-79.3). The overall rate of PSM was 33.5%. PSM was associated with biochemical recurrence (P<0.001). Overall mortality was not associated with positive margins. A clinical stage> T1c was an independent predictor of PSM on multivariate analysis (P=0.01).

CONCLUSION

PSM would increase the risk of biochemical recurrence with no impact on survival. Clinical stage>T1c was an adverse predictor for PSM.

LEVEL OF EVIDENCE

3.

Predictive Factors for Positive Surgical Margins in Patients With Prostate Cancer After Radical Prostatectomy: A Systematic Review and Meta-Analysis

Background and Objectives

Previous studies have demonstrated that positive surgical margins (PSMs) were independent predictive factors for biochemical and oncologic outcomes in patients with prostate cancer (PCa). This study aimed to conduct a meta-analysis to identify the predictive factors for PSMs after radical prostatectomy (RP).

Methods

We selected eligible studies via the electronic databases, such as PubMed, Web of Science, and EMBASE, from inception to December 2020. The risk factors for PSMs following RP were identified. The pooled estimates of standardized mean differences (SMDs)/odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. A fixed effect or random effect was used to pool the estimates. Subgroup analyses were performed to explore the reasons for heterogeneity.

Results

Twenty-seven studies including 50,014 patients with PCa were eligible for further analysis. The results showed that PSMs were significantly associated with preoperative prostate-specific antigen (PSA) (pooled SMD = 0.37; 95% CI: 0.31–0.43; P < 0.001), biopsy Gleason Score (<6/≥7) (pooled OR = 1.53; 95% CI:1.31–1.79; P < 0.001), pathological Gleason Score (<6/≥7) (pooled OR = 2.49; 95% CI: 2.19–2.83; P < 0.001), pathological stage (<T2/≥T3) (pooled OR = 3.90; 95% CI: 3.18–4.79; P < 0.001), positive lymph node (PLN) (pooled OR = 3.12; 95% CI: 2.28–4.27; P < 0.001), extraprostatic extension (EPE) (pooled OR = 4.44; 95% CI: 3.25–6.09; P < 0.001), and seminal vesicle invasion (SVI) (pooled OR = 4.19; 95% CI: 2,87–6.13; P < 0.001). However, we found that age (pooled SMD = 0.01; 95% CI: −0.07–0.10; P = 0.735), body mass index (BMI) (pooled SMD = 0.12; 95% CI: −0.05–0.30; P = 0.162), prostate volume (pooled SMD = −0.28; 95% CI: −0.62–0.05; P = 0.097), and nerve sparing (pooled OR = 0.90; 95% CI: 0.71–1.14; P = 0.388) had no effect on PSMs after RP. Besides, the findings in this study were found to be reliable by our sensitivity and subgroup analyses.

Conclusions

Preoperative PSA, biopsy Gleason Score, pathological Gleason Score, pathological stage, positive lymph node, extraprostatic extension, and seminal vesicle invasion are independent predictors of PSMs after RP. These results may helpful for risk stratification and individualized therapy in PCa patients.

Risk of biochemical recurrence based on extent and location of positive surgical margins after robot-assisted laparoscopic radical prostatectomy

Background

There are no published studies on the simultaneous effect of extent and location of positive surgical margins (PSMs) on biochemical recurrence (BCR) after robot-assisted laparoscopic prostatectomy (RALP). The aim was to report the incidence, extent, and location of PSMs over the inclusion period as well as the rates of BCR and cancer-related mortality, and determine if BCR is associated with PSM extent and/or location.

Methods

Retrospective review of 530 consecutive patients who underwent RALP between 2003 and 2012. Kaplan-Meier (KM) survival analyses and Cox regressions were performed to determine variables associated with BCR.

Results

For the 530 operated patients, evaluated at a median of 92 months (IQR, 87–99), PSMs were observed in 156 (29%), of which 24% were focal. Out of 172 PSMs, 126 (73%) were focal and 46 (27%) were extensive. The KM survival using BCR as endpoint was 0.81 (CI, 0.78–0.85) at 5 years and was 0.67 (CI, 0.61–0.72) at 10 years; and using cancer-related mortality as endpoint was 0.99 (CI, 0.99–1.00) at 5 years and 0.95 (CI, 0.92–0.98) at 10 years. Multi-variable analysis revealed the strongest predictors of BCR to be Gleason score ≥ 8 (HR = 7.97; CI, 4.38–14.51) and 4 + 3 (HR = 3.88; CI, 2.12–7.07), lymph nodes invasion (HR = 3.42; CI, 1.70–6.91), pT stage 3b or 4 (HR = 3.07; CI, 1.93–4.90), and extensive apical PSMs (HR = 2.62; CI, 1.40–4.90) but not focal apical PSMs (HR = 0.86; CI, 0.49–1.50; p = 0.586).

Conclusion

Extensive apical PSMs significantly increased the risk of BCR, independently from pT stage, Gleason score and lymph nodes invasion, while focal apical PSMs had no significant effect on BCR.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-5229-1) contains supplementary material, which is available to authorized users.

Surgical margin status and its impact on prostate cancer prognosis after radical prostatectomy: a meta-analysis

Background and purpose

Positive surgical margins (PSMs) correlate with adverse outcomes in numerous solid tumours. However, the prognostic value of PSMs in prostate cancer (PCa) patients who underwent radical prostatectomy remains unclear. Herein, we performed a meta-analysis to evaluate the association between PSMs and the prognostic value for biochemical recurrence-free survival (BRFS), cancer-specific survival (CSS), overall survival (OS), cancer-specific mortality (CSM) and overall mortality (OM) in PCa patients.

Materials and methods

According to the PRISMA statement, online databases PubMed, EMBASE and Web of Science were searched to identify relevant studies published prior to February 2018. The hazard ratios (HRs) and 95% confidence intervals (95% CIs) were calculated to evaluate the relationship between PSMs and PCa.

Results

Ultimately, 32 cohort studies that met the eligibility criteria and involved 141,222 patients (51–65,633 per study) were included in this meta-analysis. The results showed that PSMs were significantly predictive of poorer BRFS (HR = 1.35, 95% CI 1.28–1.48, p < 0.001), CSS (HR = 1.49, 95% CI 1.16–1.90, p = 0.001) and OS (HR = 1.11, 95% CI 1.02–1.20, p = 0.014). In addition, PSMs were significantly associated with higher risk of CSM (HR = 1.23, 95% CI 1.16–1.30, p < 0.001) and OM (HR = 1.09, 95% CI 1.02–1.16, p = 0.009) in patients with PCa.

Conclusions

Our study suggests that the presence of a histopathologic PSM is associated with the clinical outcomes BRFS, CSS, OS, CSM and OM in patients with PCa, and PSMs could serve as a poor prognostic factor for patients with PCa.

Electronic supplementary material

The online version of this article (10.1007/s00345-018-2333-4) contains supplementary material, which is available to authorized users.

Comparative study of separation between ex vivo prostatic malignant and benign tissue using electrical impedance spectroscopy and electrical impedance tomography

OBJECTIVE

Currently no efficient and reliable technique exists to routinely assess surgical margins during a radical prostatectomy. Electrical impedance spectroscopy (EIS) has been reported as a potential technique to provide surgeons with real-time intraoperative margin assessment. In addition to providing a quantified measure of margin status, a co-registered electrical impedance tomography (EIT) image presented on a surgeon's workstation could add value to the margin assessment process.

APPROACH

To investigate this, we conducted a comparative study between EIS and EIT to evaluate the potential these technologies might have for margin assessment. EIS and EIT data was acquired from ex vivo human prostates using a multi-electrode endoscopic impedance acquisition probe.

MAIN RESULTS

EIS and EIT show good predictive performance with a 0.76 and 0.80 area-under-curve (AUC), respectively, when considering discrete frequencies only. A machine learning (ML) algorithm is implemented to combine features, which improves the AUCs of EIS and EIT to 0.84 and 0.85, respectively. Single-step EIT takes significantly less time to reconstruct than multi-step EIT, yet provides similarly accurate classification results, making the single-step approach a potential candidate for real-time margin assessment. While the ML-based approach clearly exhibits benefits as compared to the single feature assessment, the decision to use EIS versus EIT is unclear since each approach performs better for different subsets of tissue classifications.

SIGNIFICANCE

The results presented in this paper corroborate our previous studies and present the strongest evidence yet that an intraoperative-capable impedance probe can be used to distinguish benign from malignant prostate tissues. An in vivo study with a large cohort will be necessary to definitively determine the preferred approach and to show the clinical effectiveness of using this technology for margin assessment.

Stratification model based on early postprostatectomy prostate-specific antigen kinetics may help to reduce the risk of overtreatment in candidates for adjuvant radiotherapy

OBJECTIVE

The aim of this study was to construct a stratification model based on early postoperative kinetics of prostate-specific antigen (PSA) to select the most suitable high-risk patients for early intervention after radical prostatectomy (RP).

MATERIALS AND METHODS

The study evaluated 205 men who had undergone RP without any adjuvant treatment. All of the patients had positive surgical margins, extracapsular extension and/or seminal vesicle invasion. The patients underwent multiple ultrasensitive PSA measurements on days 14, 30, 60 and 90 after RP, and subsequently at 3 month intervals. The ability of particular PSA measurements to predict biochemical recurrence (BCR) was assessed using the area under the curve (AUC). A sequential mathematical decision procedure was constructed to create a stratification model.

RESULTS

During the median follow-up of 45.9 months, 106 patients (51%) experienced BCR. Prediction of BCR in terms of the AUC for PSA measurements on days 14, 30, 60 and 90 after the surgery was 0.61, 0.70, 0.80 and 0.82, respectively. In the multivariate analysis, only PSA after RP remained as a predictor of progression-free survival (p < 0.001). The stratification model based on calculated cut-off values for PSA on day 30 (0.068 ng/ml) and PSA on day 60 (0.015 ng/ml) reduced the potential overtreatment rate by 37%.

CONCLUSIONS

The results imply that ultrasensitive PSA values obtained very early after RP correlate with the presence of recurrent disease in high-risk patients. Incorporating these readily available variables into risk stratification models may help to individualize the administration of adjuvant radiotherapy and thus to minimize overtreatment.

Do all men with pathological Gleason score 8-10 prostate cancer have poor outcomes? Results from the SEARCH database

OBJECTIVE

To determine whether there are subsets of men with pathological high grade prostate cancer (Gleason score 8-10) with particularly high or low 2-year biochemical recurrence (BCR) risk after radical prostatectomy (RP) when stratified into groups based on combinations of pathological features, such as surgical margin status, extracapsular extension (ECE) and seminal vesicle invasion (SVI).

MATERIALS AND METHODS

We identified 459 men treated with RP with pathological Gleason score 8-10 prostate cancer in the SEARCH database. The men were stratified into five groups based on pathological characteristics: group 1, men with negative surgical margins (NSMs) and no ECE; group 2, men with positive surgical margin (PSMs) and no ECE; group 3, men with NSMs and ECE; group 4, men with PSMs and ECE; and group 5, men with SVI. Cox proportional hazards models and the log-rank test were used to compare BCR among the groups.

RESULTS

At 2 years after RP, pathological group was significantly correlated with BCR (log-rank, P < 0.001) with patients in group 5 (+SVI) having the highest BCR risk (66%) and those in group 1 (NSMs and no ECE) having the lowest risk (14%). When we compared groups 2, 3, and 4, with each other, there was no significant difference in BCR among the groups (~50% 2-year BCR risk; log-rank P = 0.28). Results were similar when adjusting for prostate-specific antigen, age, pathological Gleason sum and clinical stage, or after excluding men who received adjuvant therapy.

CONCLUSIONS

In patients with high grade (Gleason score 8-10) prostate cancer after RP, the presence of either PSMs, ECE or SVI was associated with an increased risk of early BCR, with a 2-year BCR risk of ≥50%. Conversely, men with organ-confined margin-negative disease had a very low risk of early BCR despite Gleason score 8-10 disease.

3D Microendoscopic Electrical Impedance Tomography for Margin Assessment During Robot-Assisted Laparoscopic Prostatectomy

Radially configured microendoscopic electrical impedance probes intended for intraoperative surgical margin assessment during robot-assisted laparoscopic prostatectomy (RALP) were examined through simulation, bench-top experimentation, and ex vivo tissue studies. Three probe designs with 8, 9, and 17 electrodes, respectively, were analyzed through finite element method based simulations. One mm diameter spherical inclusions ( σinclusion = 1 S/m) are positioned at various locations within a hemispherical background ( σbackground = 0.1 S/m) of radius 5 mm. An 8-electrode configuration is not able to localize the inclusion at these positions while 9 and 17-electrode configurations are able to accurately reconstruct the inclusion at maximum depth of 1 mm and 3 mm, respectively. All three probe designs were constructed and evaluated using saline phantoms and ex vivo porcine and human prostate tissues. The 17-electrode probe performed best in saline phantom studies, accurately reconstructing high contrast, 1-mm-diameter metal cylindrical inclusions in a saline bath ( σsaline = 0.1 S/m) with a position and area error of 0.46 mm and 0.84 mm2, respectively. Additionally, the 17-electrode probe was able to adequately distinguish cancerous from benign tissues in three ex vivo human prostates. Simulations, bench-top saline experiments, and ex vivo tissue sampling suggest that for intraoperative surgical margin assessment during RALP, the 17-electrode probe (as compared to an 8 and 9 electrode probe) will be necessary to provide sufficient accuracy and sensitivity.

An integrated widefield imaging and spectroscopy system for contrast-enhanced, image-guided resection of tumors

Tumor recurrence following surgery is a common and unresolved medical problem of great importance since surgery is the most widely used treatment for solid-mass tumors worldwide. A contributing factor to tumor recurrence is the presence of residual tumor remaining at or near the surgical site following surgery.

GOAL

The primary objective of this study was to develop and evaluate an image-guided surgery system based on a near-infrared, handheld excitation source and spectrograph in combination with a widefield video imaging system.

METHODS

This system was designed to detect the fluorescence of near-infrared contrast agents and, in particular, indocyanine green (ICG). The imaging system was evaluated for its optical performance and ability to detect the presence of ICG in tumors in an ectopic murine tumor model as well as in spontaneous tumors arising in canines.

RESULTS

In both settings, an intravenous ICG infusion provided tumor contrast. In both the murine models and surgical specimens from canines, ICG preferentially accumulated in tumor tissue compared to surrounding normal tissue. The resulting contrast was sufficient to distinguish neoplasia from normal tissue; in the canine surgical specimens, the contrast was sufficient to permit identification of neoplasia on the marginal surface of the specimen.

CONCLUSION

These results demonstrate a unique concept in image-guided surgery by combining local excitation and spectroscopy with widefield imaging.

SIGNIFICANCE

The ability to readily detect ICG in canines with spontaneous tumors in a clinical setting exemplifies the potential for further clinical translation; the promising results of detecting neoplasia on the marginal specimen surface underscore the clinical utility.

Prostate-specific antigen doubling time subsequent to radical prostatectomy is a predictor of outcome following salvage external beam radiation therapy: a single-centre experience

OBJECTIVE

The aim of this study was to review the impact of salvage external beam radiotherapy (EBRT) of postprostatectomy patients with long-term follow-up on biochemical-free recurrence (BFR) and metastatic-free survival, and to describe pathological and clinical predictors of outcome.

MATERIALS AND METHODS

In the period 1987-2010, 76 postprostatectomy patients with biochemical and clinical recurrence received salvage EBRT. Patients were treated with conformal EBRT and 68 (90%) received a dose of 70 Gy; eight patients (10%) received a dose of 60-64 Gy. No patients received adjuvant or neoadjuvant androgen deprivation therapy in conjunction with salvage EBRT.

RESULTS

The median follow-up time after salvage EBRT was 82 months (range 5-192 months). Seventeen patients (22%) developed biochemical recurrence subsequent to postprostatectomy salvage EBRT during the observation time, and the overall 50 and 75 month actuarial BFR rates after salvage EBRT were 84% and 79%, respectively. Seven patients (9%) developed metastatic disease and two patients died of prostate cancer. Independent predictors of biochemical recurrence were seminal vesicle invasion (SVI) in the prostatectomy specimen (p < 0.05) and prostate-specific antigen doubling time (PSADT) of 6 months or less (p = 0.041) before salvage EBRT.

CONCLUSIONS

Salvage EBRT provides effective long-term BFR and metastatic-free survival in a selected group of patients with detectable, rising prostate-specific antigen values following radical prostatectomy. SVI and PSADT are prognostic variables for a non-durable response to salvage EBRT and thus predictors of high-risk prostate cancer in patients in whom neoadjuvant and adjuvant androgen deprivation therapy should be considered.