Co-registration of MRI and ultrasound: accuracy of targeting based on radiology-pathology correlation

Prostate Stereotactic Body Radiation Therapy With a Focal Simultaneous Integrated Boost: 5-Year Toxicity and Biochemical Recurrence Results From a Prospective Trial

PURPOSE

Stereotactic body radiation therapy (SBRT) is increasingly used as a definitive treatment option for patients with prostate adenocarcinoma. The aim of this study was to assess the late toxicity, patient-reported quality of life outcomes, and biochemical recurrence rates after prostate SBRT with simultaneous integrated boost (SIB) targeting lesions defined by magnetic resonance imaging (MRI).

METHODS AND MATERIALS

Patients were eligible if they had biopsy-proven low- or intermediate-risk prostate adenocarcinoma, one or more focal lesions on MRI, and an MRI-defined total prostate volume of <120 mL. All patients received SBRT delivered to the entire prostate to a dose of 36.25 Gy in 5 fractions with an SIB to the lesions seen on MRI to 40 Gy in 5 fractions. Late toxicity was defined as any possible treatment-related adverse event occurring after 3 months from the completion of SBRT. Patient-reported quality of life was ascertained using standardized patient surveys.

RESULTS

A total of 26 patients were enrolled. Six patients (23.1%) had low-risk disease and 20 patients had intermediate-risk disease (76.9%). Seven patients (26.9%) received androgen deprivation therapy. Median follow-up was 59.5 months. No biochemical failures were observed. Three patients (11.5%) experienced late grade 2 genitourinary (GU) toxicity requiring cystoscopy, and 7 patients (26.9%) had late grade 2 GU toxicity requiring oral medications. Three patients (11.5%) had late grade 2 gastrointestinal toxicity characterized by hematochezia requiring colonoscopy and steroids per rectum. There were no grade 3 or higher toxicity events observed. The patient-reported quality-of-life metrics at the time of last follow-up were not significantly different than the pre-treatment baseline.

CONCLUSIONS

The results of this study support that SBRT to the entire prostate to a dose of 36.25 Gy in 5 fractions with focal SIB to 40 Gy in 5 fractions has excellent biochemical control and is not associated with undue late gastrointestinal or GU toxicity or long-term quality of life decrement. Focal dose escalation with an SIB planning approach may be an opportunity to improve biochemical control while limiting dose to nearby organs at risk.

Value of extra-target prostate biopsy for the detection of magnetic resonance imaging-missed adverse pathology according to the Prostate Imaging Reporting and Data System scores: Spatial analysis using magnetic resonance-ultrasound fusion images

OBJECTIVES

To clarify who benefits from extra-target sampling of systematic prostate biopsy to detect magnetic resonance imaging-missed significant cancer and upgrading, when concurrently carried out with magnetic resonance imaging-ultrasound fusion targeted biopsy.

METHODS

Targeted biopsy and systematic biopsy were carried out in 301 men with Prostate Imaging Reporting and Data System scores ≥3. All score ≥3 regions were designated as targets. According to patients' highest Prostate Imaging Reporting and Data System scores, spatial relations between targets and biopsy-proven cancer were investigated to identify magnetic resonance imaging-missed pathology.

RESULTS

Overall, targeted biopsy and systematic biopsy detected significant cancer in 56.5% and 46.5%, respectively (P < 0.001). Significant cancer was detected only by systematic biopsy in 7.0%, and only outside targets in 5.0%. Upgrading by systematic biopsy was observed in 16.3%, and occurred outside targets in 11.0%. On multivariate analysis, the highest Prostate Imaging Reporting and Data System 4 was predictive for significant cancer only outside targets (odds ratio 5.81, P = 0.002) and for upgrading derived from outside targets (odds ratio 2.64, P = 0.012). According to the scores of 3, 4 and 5, significant cancer was identified only outside targets in 1.0%, 11.2% and 2.9%, respectively (P = 0.003 for Prostate Imaging Reporting and Data System 3 vs 4; P = 0.019 for Prostate Imaging Reporting and Data System 4 vs 5), and upgrading occurred in 6.1%, 18.4% and 8.6%, respectively (P = 0.009 and 0.040).

CONCLUSIONS

Men with the highest Prostate Imaging Reporting and Data System score 4 receive the largest benefit from extra-target biopsy for magnetic resonance imaging-missed significant cancer detection and upgrading. In men with a score of 3, less adverse pathology is missed without extra-target biopsy. These findings suggest prostate biopsy strategy could be tailored according to Prostate Imaging Reporting and Data System scores.

Histomorphological analysis of false positive PI-RADS 4 and 5 lesions

INTRODUCTION

Multiparametric magnetic resonance imaging (mpMRI)/ultrasound fusion-guided biopsy, in short "targeted biopsy (TB)", is becoming more attractive as it improves the detection of clinically significant prostate cancer (CaP). The accuracy of fusion-guided biopsies is limited due to false positive radiological findings as well as to histological evidence for cancer in radiologically inconspicuous regions of the prostate. We aimed to analyze histomorphological findings on mpMRI lesions highly suspicious for CaP classified as PI-RADS 4 or PI-RADS 5 (Prostate Imaging - Recording and Data System) but cancer-negative in the biopsy of this region of interest (ROI), and to compare them with findings in radiologically inconspicuous regions.

MATERIALS AND METHODS

We re-evaluated prostate biopsies from 57 patients who underwent TB in combination with systematic standard biopsy (SB) from June 2017 to July 2018 at the University Hospital Schleswig Holstein Campus Luebeck. Out of 143 ROIs, 34 PI-RADS 4/5 cancer-negative lesions were identified and subjected to comprehensive histomorphological reevaluation. Contralateral cancer-negative SBs were used as control. Chi-square test was used for statistical analysis.

RESULTS

The frequency of histomorphological alterations including stromal, glandular, vascular, and inflammatory alterations were 97% and 79.2% in prostatic tissues from cancer-negative TBs and SBs, respectively. Stromal, glandular, and inflammatory alterations were present in the majority of biopsies from both TBs and SBs. Statistical analysis revealed no significant difference between TBs and SBs with regard to stromal, glandular, and inflammatory alterations. However, vascular abnormalities were exclusively detected in TBs (18.2%).

CONCLUSION

The frequency of histomorphological alterations is slightly higher in prostate tissues from TBs compared to SB. Only vascular alterations seem to be distinct for TBs. However, it has to be assumed that additional factors influence the false-negative rate of mpMRI/ultrasound fusion-guided TB.

Focused Submission of Tissue for Radical Prostatectomy Following Multiparametric Magnetic Resonance Imaging/Ultrasound Fusion-Targeted Biopsy

Prostate cancer can be difficult to appreciate grossly and therefore partial sampling of the gland can lead to incorrect grading, staging, or margin status. However, submitting the entire prostate is more time consuming and costly. We investigated the use of magnetic resonance imaging/ultrasound-targeted biopsy for the selective submission of prostatectomy specimens. We performed a retrospective review for patients with cancer on targeted prostate biopsy who underwent subsequent radical prostatectomy. Prostatectomy specimens were submitted in their entirety and assessed for Grade Group, extraprostatic extension (EPE), margins, and number of blocks. For Targeted-Grossing (TG) assessment, apex margin, bladder neck margin, seminal vesicles, and vas deferens sections were included. For the remainder of the prostate, only sections from areas shown to be positive for cancer on targeted biopsy were included in the analysis. With total tissue submission, EPE was found in 39/81 (48.1%) cases and positive margins in 19/81 (23.5%) cases. The TG method required significantly fewer blocks: 15.8 ± 5.9 versus 44.9 ± 11.9 (P < .0001). The TG method would have diagnosed the correct stage in 73/81 (90.1%) cases, Grade Group in 74/81 (91.4%) cases, and margin status in 79/81 (97.5%) cases. EPE was missed completely by the TG method in 7 cases (P = .008), of which 5/7 (71.4%) had focal EPE. There was no significant difference in stage (P = .24), Grade Group (P = .95), or margin status (P = .16) between the 2 methods. Grossing utilizing selective tissue submission from areas found to be positive for prostate cancer on magnetic resonance imaging/ultrasound-targeted prostate biopsy remains inferior to complete submission of tissue for radical prostatectomy specimens.

Prostate Stereotactic Body Radiation Therapy With a Focal Simultaneous Integrated Boost: Acute Toxicity and Dosimetry Results From a Prospective Trial

Purpose

This study aimed to report the early toxicity results of a prospective clinical trial of prostate stereotactic body radiation therapy (SBRT) to the entire prostate with a simultaneous integrated boost (SIB) to magnetic resonance imaging (MRI)-defined focal lesions.

Methods and materials

Eligible patients included men with biopsy-proven prostate stage T1c to T2c adenocarcinoma, a Gleason score ≤7, and prostate-specific antigen values of ≤20 ng/mL, who had at least 1 focal lesion visible on MRI and a total prostate volume no greater than 120 cm³. SBRT consisted of a dose of 36.25 Gy to the entire prostate with an SIB of 40 Gy to the MRI-defined lesions, delivered in 5 fractions. The primary purpose of the study was to confirm the feasibility of treatment planning/delivery and to estimate the rate of urinary retention requiring placement of a Foley catheter within 90 days of treatment. This study was to be considered successful if urinary retention occurred in no more than 15% of cases, with a planned enrollment of at least 25 patients.

Results

A total of 26 men were enrolled, and all underwent SBRT as planned. Twenty patients (77%) had intermediate-risk features, and the remainder were low risk. A treatment plan that met the protocol-defined goals for all cases was developed. Two patients (7.7%) developed acute urinary symptoms that required the temporary placement of a Foley catheter. No grade 3+ toxicity events were observed.

Conclusions

Planning and delivery of prostate SBRT with a whole prostate dose of 36.25 Gy and a focal 40 Gy SIB is feasible. Early follow-up suggests that this treatment is not associated with undue morbidity.