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

Impact of prostate radiotherapy on survival outcomes in clinically node-positive prostate cancer: A multicentre retrospective analysis

PURPOSE

To evaluate clinical outcomes for cN1M0 prostate cancer treated with varied modalities.

MATERIALS AND METHODS

Men with radiological stage cN1M0 prostate cancer on conventional imaging, treated from 2011-2019 with various modalities across four centres in the UK were included. Demographics, tumour grade and stage, and treatment details were collected. Biochemical and radiological progression-free survival (bPFS, rPFS) and overall survival (OS) were estimated using Kaplan Meier analyses. Potential factors impacting survival were tested with univariable log-rank test and multivariable Cox-proportional hazards model.

RESULTS

Total 337 men with cN1M0 prostate cancer were included, 47% having Gleason grade group 5 disease. Treatment modalities included androgen deprivation therapy (ADT) in 98.9% men, either alone (19%) or in combinations including prostate radiotherapy (70%), pelvic nodal radiotherapy (38%), docetaxel (22%), or surgery (7%). At median follow up of 50 months, 5-year bPFS, rPFS, and OS were 62.7%, 71.0%, and 75.8% respectively. Prostate radiotherapy was associated with significantly higher bPFS (74.1% vs 34.2%), rPFS (80.7% vs 44.3%) and OS (86.7% vs 56.2%) at five years (log rank p < 0.001 each). On multivariable analysis including age, Gleason grade group, tumour stage, ADT duration, docetaxel, and nodal radiotherapy, benefit of prostate radiotherapy persisted for bPFS [HR 0.33 (95% CI 0.18-0.62)], rPFS [HR 0.25 (0.12-0.51)], and OS [HR 0.27 (0.13-0.58)] (p < 0.001 each). Impact of nodal radiotherapy or docetaxel was not established due to small subgroups.

CONCLUSION

Addition of prostate radiotherapy to ADT in cN1M0 prostate cancer yielded improved disease control and overall survival independent of other tumour and treatment factors.

"Meta-analysis of elective pelvic nodal irradiation using moderate hypofractionation for high-risk prostate cancer" (MENHYP-ENI)

OBJECTIVES

Despite several advances in planning and delivery of radiotherapy (RT) for prostate cancer, the role of elective pelvic nodal irradiation (EPNI) remains controversial for high-risk disease. We performed a meta-analysis to evaluate the outcomes of patients treated with moderate hypofractionated RT (MHF-RT) with EPNI using modern radiotherapy techniques.

METHODS

Eligible studies were identified on Medline, Embase, the Cochrane Library, and proceedings of annual meetings through October 2021. We followed the PRISMA and MOOSE guidelines. A meta-regression analysis was performed to assess a possible correlation between selected variables and outcomes. A p-value <0.05 was considered significant.

RESULTS

Eighteen studies with a total of 1745 patients, median follow-up 61 months, treated with EPNI employing MHF-RT were included. The biochemical relapse-free survival (bRFS) at 5-, 7- and 10-year was 90% (95% CI 88-94%), 83% (95%CI 78-91%) and 78% (95%CI 68-88%). The 5-year prostate cancer-specific survival, disease-free survival, distant metastases-free survival and overall survival were 98% (95%CI 97-99%), 88.7% (95%CI 85-93%), 91.2% (95%CI 88-92%), and 93% (95%CI 90-96%), respectively. The rates of local, pelvic, and distant recurrence were 0.38% (95%CI 0-2%), 0.13% (95%CI 0-1.5%), and 7.35% (95%CI 2-12%), respectively. The rate of late GI and GU toxicity grade ≥ 2 were 6.7% (95%CI 4-9%), and 11.3% (95%CI 7.6-15%), with heterogeneity, but with rare cases of toxicity grade 3-5.

CONCLUSION

EPNI with concomitant MHF-RT provides satisfactory bRFS in the long-term follow-up, with low rates of GU and GI severe toxicities and minimal pelvic and local failure.

Clinical outcomes of definitive whole pelvic radiotherapy for clinical lymph node metastatic prostate cancer

Background

In this study, we aim to present the clinical outcomes of radiotherapy (RT) in clinical pelvic lymph node‐positive prostate cancer (cN1) patients. We also analyze the prognostic factors with focus on RT dose escalation to metastatic lymph nodes (LN).

Methods

We retrospectively analyzed the data from cN1 patients who were treated with definitive RT and androgen deprivation therapy (ADT) between June 2004 and February 2016. All patients received localized irradiation to the prostate region and whole pelvis irradiation. Some patients received intensity‐modulated radiation therapy with RT dose escalation to metastatic LN. Univariate analyses using log‐rank test were performed to find prognostic factors between patient subgroups.

Results

Fifty‐one consecutive patients were identified. The median follow‐up period for all patients was 88 (range 20‐157) months. Primary Gleason pattern and LN RT dose were statistically significant prognostic factors for relapse‐free survival (RFS) and distant metastasis‐free survival (DMFS). Especially, RT dose escalation (60 Gy or more) to metastatic LN significantly improved RFS and DMFS compared with standard dose RT (4‐year RFS 90.6% vs 82.1%, 7‐year RFS 90.6% vs 58.0%, P = .015; 4‐year DMFS 90.6% vs 82.1%, 7‐year DMFS 90.6% vs 62.8%, P = .023). The following factors were all statistically significant for biochemical relapse‐free survival (BRFS): T stage, LN RT dose, local RT dose, and ADT duration period. Any significantly different toxicity was not seen for each LN or local RT dose except for the incident rate of grade 2 or more acute urinary retention, which was significantly higher in the higher LN RT dose (60 Gy or more) group by the Chi‐square test.

Conclusions

RT dose escalation to metastatic LN in cN1 patients improves BRFS, RFS, and DMFS at 4 and 7 years, without increasing severe adverse events.

Elective Pelvic Nodal Irradiation With a Simultaneous Hypofractionated Integrated Prostate Boost for Localised Prostate Cancer: Ready for Prime Time?

External beam radiotherapy is a standard treatment option for localised prostate cancer and hypofractionation has become an alternative to conventionally fractionated radiotherapy. In patients who receive external beam radiotherapy, elective pelvic nodal irradiation is sometimes delivered, especially in patients with unfavourable disease who are at risk of micrometastatic spread of cancer into the regional nodes. One elegant approach to combine prostate hypofractionation with elective pelvic nodal irradiation is with a simultaneous integrated boost technique, where a radical hypofractionated dose is delivered to the prostate while the regional pelvic nodes receive a lower microscopic dose simultaneously in a single radiotherapy plan over the same number of treatment fractions. This article reviews the existing published literature evaluating such an approach.

Feasibility of Dose Escalating [18F]fluciclovine Positron Emission Tomography Positive Pelvic Lymph Nodes During Moderately Hypofractionated Radiation Therapy for High-Risk Prostate Cancer

Purpose

The aim of this study was to report the treatment planning feasibility of dose escalation to suspicious lymph nodes (LNs) for a series of men who underwent pretreatment [¹⁸F]fluciclovine positron emission tomography (PET)/magnetic resonance imaging (MRI).

Methods and Materials

Cases of men with prostate cancer who enrolled in a clinical trial of pretreatment [¹⁸F]fluciclovine PET who had suspicious LNs were selected. Pelvic LNs <1 cm were defined as positive based on [¹⁸F]fluciclovine-PET if their maximum standardized uptake value (SUV_max) was ≥1.3-fold greater than the reference blood pool SUV_mean, and LNs ≥1 cm were defined as positive if the SUV was greater than the reference SUV bone marrow reference. For each case, a radiation treatment plan was generated to deliver 70 Gy to the prostate and proximal seminal vesicles, 60.2 Gy to the PET-positive LNs, and 50.4 Gy to the elective nodal regions, simultaneously in 28 fractions of 2.5 Gy, 2.15 Gy, and 1.8 Gy, respectively. Treatment planning goals were defined a priori. The resulting target volume and organ-at-risk dosimetry were compared with the original treatment plan.

Results

Four cases were identified, with between 1 and 5 [¹⁸F]fluciclovine PET–positive LNs each. Goals for the prostate and elective nodal target volumes were successfully met in all cases. The goal of covering more than 90% of the positive LN planning target volume by the prescription dose of 60.2 Gy was met in 3 of the 4 cases. This goal was not met in 1 case, but 100% of clinical target volume was covered by 60.2 Gy. The primary organ-at-risk tradeoff was that a small volume (0.5-8.2 cm³) of small bowel would receive ≥54 Gy in each case.

Conclusions

These preliminary results suggest that [¹⁸F]fluciclovine PET/MRI directed dose escalation of suspicious pelvic LNs is likely feasible in the setting of definitive radiation therapy. The potential clinical benefit of dose escalating [¹⁸F]fluciclovine PET–positive LNs should be investigated in a prospective clinical trial.

Dosimetric and clinical outcomes after volumetric modulated arc therapy for carcinoma of the thoracic esophagus

Purpose

The efficiency of radiation delivery via volumetric modulated arc therapy (VMAT) is indisputable, but outcomes after VMAT for thoracic esophageal carcinoma are largely unknown.

Methods and materials

We retrospectively analyzed 65 patients with thoracic esophageal cancer who received VMAT to 50.4 Gy (range, 45-50.4 Gy) with concurrent chemotherapy from November 2012 to March 2016 at a single tertiary cancer center. We then used propensity score matching to match these 65 patients with 130 other patients treated with step-and-shoot intensity modulated radiation therapy (ssIMRT) and concurrent chemotherapy. Differences in continuous and categorical variables were examined with independent-sample t or Wilcoxon tests and χ² tests.

Results

Dosimetrically, VMAT had a higher conformity index (87.75 ± 10.70 VMAT vs 83.20 ± 9.42 ssIMRT, P = .003), a higher heart V5, and a lower V50 than ssIMRT, but lung V5-20, heart V30, heart V40, cord_max, and homogeneity index were similar. At median follow-up intervals of 14.3 months (range, 3.8-34.5 months) for VMAT and 31.8 months (range, 1.8-117.2 months) for ssIMRT, overall survival rates were similar between the treatments (93.5% VMAT vs 91.5% ssIMRT at 1 year; 60.0% VMAT and 61.4% ssIMRT at 2 years; P = .868). Recurrence-free survival rates were similar (73.3% VMAT vs 79.5% ssIMRT at 1 year, 59.9% VMAT and 61.8% ssIMRT at 2 years; P = .614), as were pathologic complete response rates (31.2% VMAT vs 23.3% ssIMRT; P = .41) and toxicity and postoperative complications (radiation pneumonitis 9% VMAT vs 15.4% ssIMRT; pericardial effusion 2% VMAT vs 7% ssIMRT; esophageal fistula and stricture 9% VMAT vs 13% ssIMRT; all P > .05).

Conclusion

Compared with ssIMRT, VMAT had better target conformity with similar organ sparing and comparable rates of survival, recurrence, and toxicity. These results suggest that VMAT can be safe and effective for esophageal cancer.

An IGRT margin concept for pelvic lymph nodes in high-risk prostate cancer

Purpose

Gold-marker-based image-guided radiation therapy (IGRT) of the prostate allows to correct for inter- and intrafraction motion and therefore to safely reduce margins for the prostate planning target volume (PTV). However, pelvic PTVs, when coadministered in a single plan (registered to gold markers [GM]), require reassessment of the margin concept since prostate movement is independent from the pelvic bony anatomy to which the lymphatics are usually referenced to.

Methods

We have therefore revisited prostate translational movement relative to the bony anatomy to obtain adequate margins for the pelvic PTVs compensating mismatch resulting from referencing pelvic target volumes to GMs in the prostate. Prostate movement was analyzed in a set of 28 patients (25 fractions each, totaling in 684 fractions) and the required margins calculated for the pelvic PTVs according to Van Herk’s margin formula \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$M=2.5\Upsigma +1.64\left (\sigma^{\prime}-\sigma _{p}\right )$$\end{document}M=2.5Σ+1.64σ′-σp.

Results

The overall mean prostate movement relative to bony anatomy was 0.9 ± 3.1, 0.6 ± 3.4, and 0.0 ± 0.7 mm in anterior/posterior (A/P), inferior/superior (I/S) and left/right (L/R) direction, respectively. Calculated margins to compensate for the resulting mismatch to bony anatomy were 9/9/2 mm in A/P, I/S, and L/R direction and 10/11/6 mm if an additional residual error of 2 mm was assumed.

Conclusion

GM-based IGRT for pelvic PTVs is feasible if margins are adapted accordingly. Margins could be reduced further if systematic errors which are introduced during the planning CT were eliminated.

68 Ga-PSMA-PET for radiation treatment planning in prostate cancer recurrences after surgery: Individualized medicine or new standard in salvage treatment

BACKGROUND

⁶⁸ Ga-PSMA-PET imaging is a novel promising diagnostic tool to locate early biochemical failure after radical prostatectomy (RP) in prostate cancer (PC) patients. Exact knowledge of the relapse location may result in changes of the therapy concept aside from changes to the TNM stage. To gain data for this approach, we evaluated PC patients receiving ⁶⁸ Ga-PSMA-PET imaging before salvage radiotherapy (RT).

METHODS AND MATERIALS

In this study, 100 patients with biochemical failure after RP± prior RT who underwent ⁶⁸ Ga-PSMA PET/CT or PET/MRI were evaluated undergoing salvage RT in our department. We analyzed TNM staging changes due to ⁶⁸ Ga-PSMA-PET imaging and its influence on RT planning and treatment.

RESULTS

Uptake indicative for tumor recurrence in ⁶⁸ Ga-PSMA-PET was found in 76% of the patients with biochemical recurrent PC. Median PSA level was 1.0 ng/mL (range 0.12-14.7 ng/mL). Of these, 80% showed no morphological correlate in the corresponding CT or MRI. A 43% of all patients experienced a change in TNM stage due to ⁶⁸ Ga-PSMA-PET imaging. Patients had changes from Tx to rcT+ (28%), 12% from pN0 to rcN1, 1% from pN0/cM0 to rcM1a, and 8% from cM0 to rcM1b. Due to the additional knowledge of ⁶⁸ Ga-PSMA-PET imaging, initial planned RT planning was adapted in 59% of all cases. An additional simultaneous integrated boost (SIB) to the prostate bed or lymph nodes was given to 32% and 63%, respectively. Ten patients received stereotactic body RT (SBRT) to single bone metastases.

CONCLUSION

⁶⁸ Ga-PSMA-PET imaging showed a high clinical impact on staging and RT management in patients with biochemically recurrent PC, even at low serum PSA levels. With 43% changes in staging and 59% in radiotherapy planning ⁶⁸ Ga-PSMA-PET could lead to an indispensable tool in guiding radiation treatment in recurrent PC.

Adjuvant radiotherapy after radical cystectomy for patients with muscle invasive bladder cancer: a phase II trial

Background

Neo-adjuvant chemotherapy followed by radical cystectomy with extended pelvic lymph node dissection is considered to be the treatment of choice for patients with muscle invasive bladder cancer (MIBC). Despite this aggressive treatment the outcome is poor and ultimately, 30% of the patients with ≥pT3 tumors develop a pelvic recurrence. We hypothesize that postoperative adjuvant external beam radiotherapy (EBRT) might prevent local and lymph node recurrence and improve disease free- and overall survival as loco-regional recurrence is linked to the development of distant metastasis.

Methods

We plan to perform a multicentric prospective phase two study including 76 patients. Eligible patients are patients with MIBC, treated with radical cystectomy and presenting with ≥1 of the following characteristics:

Pathological (p)T3 stage + presence of lymphovascular invasion on pathological examination

pT4 stage

<10 lymph nodes removed

positive lymph nodes

positive surgical margins

Patients will have a ¹⁸F–FDG PET-CT to rule out the presence of distant metastasis prior to EBRT. A median dose of 50 Gy in 25 fractions is prescribed to the pelvic lymph node regions with inclusion of the operative bladder bed in case of a positive surgical margin. Patients with suspected lymph nodes on PET- CT can still be included in the trial, but a simultaneous integrated boost to 74Gy to the positive lymph nodes will be delivered. Blood and urine samples will be collected on day-1 and last day of EBRT for evaluation of biomarkers. The primary endpoint is evaluation of acute ≥Grade 3 intestinal or grade 4 urinary toxicity, in case of a neo-bladder reconstruction, within 12 weeks after EBRT. Secondary endpoints are: assessment of QOL, late RTOG toxicity, local control, disease free survival and overall survival. Biomarkers in urine and blood will be correlated with secondary survival endpoints.

Discussion

This is a prospective phase 2 trial re-assessing the feasibility of adjuvant radiotherapy in high-risk MIBC.

Trial registration

The Ethics committee of the Ghent University Hospital (EC2014/0630) approved this study on 31/07/2014.

Trial registration on Clinicaltrials.gov (NCT02397434) on November 19, 2014.

Twenty Fraction Prostate Radiotherapy with Intra-prostatic Boost: Results of a Pilot Study

AIMS

For patients with high-risk, locally bulky prostate cancer, an intra-prostatic boost to tumour volumes (dose-painting) offers a risk-adapted dose escalation. We evaluated the feasibility of hypofractionated dose-painting radiotherapy and the associated toxicity. The possibility to streamline a radiobiologically optimised planning protocol was also investigated.

MATERIALS AND METHODS

Twenty-eight patients were treated using a dose-painting approach; boost volumes were identified with functional magnetic resonance imaging scans. The prostate dose outside the boost volume was 60 Gy in 20 fractions, and the maximum integrated boost dose was set to 68 Gy, provided that the dose constraints to the organs at risk could be fulfilled. Rotational intensity-modulated radiotherapy was used with daily image guidance and fiducial markers.

RESULTS

The boost dose was escalated to 68 Gy for 25 patients (median dose 69 Gy, range 68-70 Gy); for three patients the boost dose was 67 Gy, due to the proximity of the urethra and/or the rectum. The mean normal tissue complication probability for rectal bleeding was 4.7% (range 3.4-5.8%) and was 3.5% for faecal incontinence (range 2.3-5.0%). At a median follow-up of 38 months (range 32-45) there was no grade 3 toxicity. Two patients developed grade 2 genitourinary toxicity (7.1%) and none developed grade 2 gastrointestinal toxicity. The mean prostate-specific antigen (PSA) for 23 patients who had stopped the adjuvant hormone therapy with a normal testosterone was 0.27 ng/ml (0.02-0.72) at follow-up; two patients have suppressed PSA and testosterone after stopping 3 year adjuvant hormone and three patients have relapsed (one pelvic node, two PSA only) at 36, 12 and 42 months, respectively.

CONCLUSIONS

A hypofractionated radiotherapy schedule, 60 Gy in 20 fractions with intra-prostatic boost dose of 68 Gy, can be achieved without exceeding dose constraints for organs at risk. Hypofractionated dose-painting escalated radiotherapy has an acceptable safety profile. The same planning protocol was used in a phase II single-arm trial (BIOPROP20: ClinicalTrials.gov identifier NCT02125175) and will further be used in a large phase III randomised trial (PIVOTALboost): patients will be randomised standard radiotherapy (60 Gy in 20 fractions) with or without lymph node radiotherapy versus dose-painting radiotherapy with or without lymph node radiotherapy; the trial will be opened for recruitment in summer 2017.

Post-Irradiation Bladder Syndrome After Radiotherapy of Malignant Neoplasm of Small Pelvis Organs: An Observational, Non-Interventional Clinical Study Assessing VESIcare®/Solifenacin Treatment Results

Background

Radiotherapy is explicitly indicated as one of the excluding factors in diagnosing overactive bladder syndrome (OAB). Nevertheless, symptoms of OAB such as urgent episodes, incontinence, pollakiuria, and nocturia, which are consequences of irradiation, led us to test the effectiveness of VESIcare^®/Solifenacin in patients demonstrating these symptoms after radiation therapy of small pelvis organs due to malignant neoplasm.

Material/Methods

We conducted an observatory clinical study including 300 consecutive patients with symptoms of post-irradiation bladder; 271 of those patients completed the study. The observation time was 6 months and consisted of 3 consecutive visits taking place at 12-week intervals. We used VESIcare® at a dose of 5 mg a day. Every sixth patient was examined urodynamically at the beginning and at the end of the observation period, with an inflow speed of 50 ml/s.

Results

We noticed improvement and decline in the average number of episodes a day in the following parameters: number of micturitions a day (−36%, P<0.01), nocturia (−50%, P<0.01), urgent episodes (−41%, P<0.03), and episodes of incontinence (−43%, P<0.01). The patients’ quality of life improved. The average maximal cystometric volume increased by 34 ml (21%, p<0.01), average bladder volume of “first desire” increased by 42 ml (49%, P<0.01), and average detrusor muscle pressure at maximal cystometric volume diminished by 9 cmH₂O (−36%, P<0.03).

Conclusions

The substance is well-tolerated. Solifenacin administered long-term to patients with symptoms of OAB after radiotherapy of a malignant neoplasm of the small pelvis organs has a daily impact in decreasing number of urgent episodes, incontinence, pollakiuria, and nocturia.

(68)Ga-PSMA-11 PET/CT: a new technique with high potential for the radiotherapeutic management of prostate cancer patients

PURPOSE

Radiotherapy is the main therapeutic approach besides surgery of localized prostate cancer. It relies on risk stratification and exact staging. This report analyses the potential of [(68)Ga]Glu-urea-Lys(Ahx)-HBED-CC ((68)Ga-PSMA-11), a new positron emission tomography (PET) tracer targeting prostate-specific membrane antigen (PSMA) for prostate cancer staging and individualized radiotherapy planning.

METHODS

A cohort of 57 patients with prostate cancer scanned with (68)Ga-PSMA-11 PET/CT for radiotherapy planning was retrospectively reviewed; 15 patients were at initial diagnosis and 42 patients at time of biochemical recurrence. Staging results of conventional imaging, including bone scintigraphy, CT or MRI, were compared with (68)Ga-PSMA ligand PET/CT results and the influence on radiotherapeutic management was quantified.

RESULTS

(68)Ga-PSMA ligand PET/CT had a dramatic impact on radiotherapy application in the presented cohort. In 50.8 % of the cases therapy was changed.

CONCLUSION

The presented imaging technique of (68)Ga-PSMA PET/CT could be a key technology for individualized radiotherapy management in prostate cancer.

A method for evaluation of proton plan robustness towards inter-fractional motion applied to pelvic lymph node irradiation

BACKGROUND

The benefit of proton therapy may be jeopardized by dose deterioration caused by water equivalent path length (WEPL) variations. In this study we introduced a method to evaluate robustness of proton therapy with respect to inter-fractional motion and applied it to irradiation of the pelvic lymph nodes (LNs) from different beam angles. Patient- versus population-specific patterns in dose deterioration were explored.

MATERIAL AND METHODS

Patient data sets consisting of a planning computed tomography (pCT) as well as multiple repeat CT (rCT) scans for three patients were used, with target volumes and organs at risk (ORs) outlined in all scans. Single beam spot scanning proton plans were optimized for the left and right LN targets separately, across all possible beam angle configurations (5° angle intervals). Isotropic margins of 0, 3, 5 and 7 mm from the clinical target volume (CTV) to the planning target volume (PTV) were investigated. The optimized fluence maps for the pCT for each beam were applied onto all rCTs and the dose distributions were re-calculated. WEPL variation for each beam angle was computed by averaging over beams eye view WEPL distributions.

RESULTS

Similarity in deterioration patterns were found for the investigated patients, with beam angles delivering less dose to rectum, bladder and overall normal tissue identified around 40° and around 150°-160° for the left LNs, and corresponding angles for the right LNs. These angles were also associated with low values of WEPL variation.

CONCLUSION

We have established and explored a method to quantify the robustness towards inter-fractional motion of single beam proton plans treating the pelvic LNs from different beam configurations and with different CTV to PTV margins. For the patients investigated we were able to identify beam orientations that were robust to dose deterioration in the target and ORs.

(11)C-acetate PET/CT in pre-therapeutic lymph node staging in high-risk prostate cancer patients and its influence on disease management - a retrospective study

BACKGROUND

Radiation treatment with simultaneous integrated boost against suspected lymph node metastases may be a curative therapeutic option in patients with high-risk prostate cancer (>15% estimated risk of pelvic lymph node metastases according to the Cagiannos nomogram). (11)C-acetate positron emission tomography/computed tomography (PET/CT) can be used for primary staging as well as for detection of suspected relapse of prostate cancer. The aims of this study were to evaluate the association between positive (11)C-acetate PET/CT findings and the estimated risk of pelvic lymph node metastases and to assess the impact of (11)C-acetate PET/CT on patient management in high-risk prostate cancer patients.

METHODS

Fifty consecutive prostate cancer patients referred for primary staging with (11)C-acetate PET/CT prior to radiotherapy with curative intention were enrolled in this retrospective study.

RESULTS

All patients showed increased (11)C-acetate uptake in the prostate. Pelvic lymph node uptake was seen in 42% (21/50) of the patients, with positive external iliac lymph nodes in 71% (15/21) of these. The overall observed proportion of PET/CT-positive pelvic lymph nodes at patient level was higher than the average estimated risk, especially in low-risk groups (<15%). There was a significant association between observed proportion and estimated risk of pelvic lymph node metastases in groups with ≤45 and >45% estimated risk. Treatment strategy was altered due to (11)C-acetate PET/CT findings in 43% (20/47) of the patients.

CONCLUSIONS

The observed proportion of (11)C-acetate PET/CT findings suggestive of locoregional metastases was higher than the estimated risk, suggesting that the Cagiannos nomogram underestimates the risk for metastases. The imaging results with (11)C-acetate PET/CT have a considerable impact on patient management.

Early results of urethral dose reduction and small safety margin in intensity-modulated radiation therapy (IMRT) for localized prostate cancer using a real-time tumor-tracking radiotherapy (RTRT) system

Background

We prospectively assessed the utility of intensity-modulated radiation therapy (IMRT) with urethral dose reduction and a small margin between the clinical target volume (CTV) and the planning target volume (PTV) for patients with localized prostate cancer.

Methods

The study population was 110 patients in low- (14.5%), intermediate- (41.8%), and high-risk (43.6%) categories. Three gold fiducial markers were inserted into the prostate. A soft guide-wire was used to identify the urethra when computed tomography (CT) scan for treatment planning was performed. A dose constraint of V70 < 10% was applied to the urethral region. Margins between the CTV-PTV were set at 3 mm in all directions. Patients were treated with 70 Gy IMRT in 30 fractions (D95 of PTV) over 7.5 weeks. The patient couch was adjusted to keep the gold markers within 2.0 mm from their planned positions with the use of frequent on-line verification.

Results

The median follow-up period was 31.3 (3.2 to 82.1) months. The biochemical relapse-free survival (bRFS) rates at 3 years were 100%, 93.8% and 89.5% for the low-, intermediate-, and high-risk patients, respectively. The incidences of acute adverse events (AEs) were 45.5% and 0.9% for grades 1 and 2, respectively. The late AEs were grade 1 cystitis in 10.0% of the patients, rectal bleeding in 7.3%, and urinary urgency in 6.4%. Only three patients (2.7%) developed grade 2 late AEs.

Conclusions

On-line image guidance with precise correction of the table position during radiotherapy achieved one of the lowest AEs rates with a bRFS equal to the highest in the literature.