Combination of dose escalation with technological advances (intensity-modulated and image-guided radiotherapy) is not associated with increased morbidity for patients with prostate cancer

Erectile function preservation after salvage radiation therapy for biochemically recurrent prostate cancer after prostatectomy: Five-year results of the SAKK 09/10 randomized phase 3 trial

Objectives

To evaluate effects of dose intensified salvage radiotherapy (sRT) on erectile function in biochemically recurrent prostate cancer (PC) after radical prostatectomy (RP).

Materials and methods

Eligible patients had evidence of biochemical failure after RP and a PSA at randomization of ≤ 2 ng/ml. Erectile dysfunction (ED) was investigated as secondary endpoint within the multicentre randomized trial (February 2011 to April 2014) in patients receiving either 64 Gy or 70 Gy sRT. ED and quality of life (QoL) were assessed using CTCAE v4.0 and the EORTC QoL questionnaires C30 and PR25 at baseline and up to 5 years after sRT.

Results

344 patients were evaluable. After RP 197 (57.3 %) patients had G0-2 ED while G3 ED was recorded in 147 (42.7 %) patients. Subsequently, sexual activity and functioning was impaired. 5 years after sRT, 101 (29.4 %) patients noted G0-2 ED. During follow-up, 44.2 % of patients with baseline G3 ED showed any improvement and 61.4 % of patients with baseline G0-2 ED showed worsening. Shorter time interval between RP and start of sRT (p = 0.007) and older age at randomization (p = 0.005) were significant predictors to more baseline ED and low sexual activity in the long-term. Age (p = 0.010) and RT technique (p = 0.031) had a significant impact on occurrence of long-term ED grade 3 and worse sexual functioning. During follow-up, no differences were found in erectile function, sexual activity, and sexual functioning between the 64 Gy and 70 Gy arm.

Conclusion

ED after RP is a known long-term side effect with significant impact on patients' QoL. ED was further affected by sRT, but dose intensification of sRT showed no significant impact on erectile function recovery or prevalence of de novo ED after sRT. Age, tumor stage, prostatectomy and RT-techniques, nerve-sparing and observation time were associated with long-term erectile function outcome.ClinicalTrials.gov. Identifier: NCT01272050.

Incidence and Management of Radiation Cystitis After Pelvic Radiotherapy for Prostate Cancer: Analysis from a National Database

OBJECTIVES

To determine the incidence of radiation cystitis on Prostate Cancer (PCa) patients undergoing pelvic radiotherapy (RT), evaluating the most used management strategies, and identifying potential risk factors associated with the development of this condition.

METHODS

A retrospective analysis was conducted using the PearlDiver™ Mariner database, containing patient records compiled between 2011 and 2022. International Classification of Diseases (ICD) and Current Procedural Terminology (CPT) codes were employed to identify population and outcomes. We evaluated patients who underwent RT for PCa and subsequently developed radiation cystitis. Primary objective was to determine the overall incidence of radiation cystitis. Furthermore, we investigated its associated risk factors and management.

RESULTS

A total of 274,865 PCa patients underwent RT during the study period. Of these, 48,713 (17.7%) experienced hematuria following RT, while 7,721 (2.8%) were diagnosed with radiation cystitis. After the diagnosis, 2,307 patients (29.9%) received diagnostic or therapeutic endoscopic interventions. Only 59 patients (0.76%) underwent endovascular embolization, while 151 patients (1.95%) required cystectomy. Hyperbaric oxygen therapy, administered to 1,287 patients (16.67%), was the only treatment that displayed a significant upward trend. Multivariate logistic regression identified obesity (OR 1.29; 95% C.I. 1.23 - 1.35), smoking (OR 1.27; 95% C.I. 1.22 - 1.33), and diabetes (OR 1.32; 95% C.I. 1.26 - 1.39), as significant risk factors for radiation cystitis (all p-values < 0.001).

CONCLUSIONS

Radiation cystitis represents a rare complication after pelvic RT with significant clinical impact. Its incidence has remained stable throughout the study period. The identified risk factors corroborate the pathophysiology of radiation cystitis. Hyperbaric oxygen therapy was the only treatment to show an upward trend during the study period.

Gastrointestinal Quality-of-Life Trajectories after Radiotherapy for Prostate Cancer-Which Patients Suffer from Persisting Problems?

Gastrointestinal toxicity, particularly in relation to rectal bleeding, is regarded as the dose-limiting toxicity in radiotherapy for prostate cancer, and it is the most frequent focus of toxicity studies [...].

Erectile dysfunction and cancer: current perspective

Erectile dysfunction (ED) is one of the major but underreported concerns in cancer patients and survivors. It can lead to depression, lack of intimacy between the couple, and impaired quality of life. The causes of erectile dysfunction are psychological distress and endocrinal dysfunction caused by cancer itself or side effect of anticancer treatment like surgery, radiotherapy, chemotherapy and hormonal therapy. The degree of ED depends on age, pre-cancer or pre-treatment potency level, comorbidities, type of cancer and its treatment. Treatment options available for ED are various pharmacotherapies, mechanical devices, penile implants, or reconstructive surgeries. A complete evaluation of sexual functioning should be done prior to starting anticancer therapy. Management should be individualized and couple counseling should be an integral part of the anticancer treatment.

Quality of life more than 10 years after radiotherapy for localized prostate cancer-impact of time after treatment and prescription dose

Purpose

Analysis of quality of life changes after radiotherapy with focus on the impact of time after treatment and prescription dose.

Methods

Consecutive patients were treated with doses from 70.2/1.8 Gy (n = 206) to 72/1.8–2.0 Gy (n = 176) in a single centre and surveyed using the Expanded Prostate Cancer Index Composite questionnaire.

Results

Urinary and bowel bother scores decreased 1 / 3 / 6 points and 7 / 7 / 9 points on average 1 / 5 / 10 years after RT in comparison to baseline scores. The rate of urinary (need of pads in 8% vs. 15% before vs. 10 years after RT; p = 0.01) and bowel (uncontrolled leakage of stool in 5% vs. 12% before vs. 10 years after RT; p < 0.01) incontinence, as well as rectal bleeding (4% vs. 8% before vs. 10 years after RT; p = 0.05) increased. Sexual function scores decreased (erections sufficient for intercourse in 36% vs. 12% before vs. 10 years after RT; p < 0.01).

A higher dose had a statistically significant impact on urinary bother and stool incontinence, but also tended to decrease urinary continence. Age and comorbidities did not have an influence on score changes, but on baseline urinary function/bother and baseline sexual function.

Conclusion

Apart from an increasing rate of erectile dysfunction, urinary and bowel incontinence rates increased with increasing follow-up period. A higher dose was found to be associated with increased urinary problems and larger stool incontinence rates. Age and comorbidities were found to be relevant for baseline scores, but not for score changes.

Application of rectal retractor for postprostatectomy salvage radiotherapy of prostate cancer: A case report and literature review

Using a rectal retractor (RR) during salvage radiotherapy after radical prostatectomy is a promising approach for reducing dose to the rectum. The patient well tolerated the daily RR insertion. This area of research encourages researchers for a comprehensive evaluation of the role of the RR in postprostatectomy radiotherapy.

ESTRO ACROP consensus guideline on the use of image guided radiation therapy for localized prostate cancer

Use of image-guided radiation therapy (IGRT) helps to account for daily prostate position changes during radiation therapy for prostate cancer. However, guidelines for the use of IGRT are scarce. An ESTRO panel consisting of leading radiation oncologists and medical physicists was assembled to review the literature and formulate a consensus guideline of methods and procedure for IGRT in prostate cases. Advanced methods and procedures are also described which the committee judged relevant to further improve clinical practice. Moreover, ranges for margins for the three most popular IGRT scenarios have been suggested as examples.

Effects of definitive and salvage radiotherapy on the distribution of lymphocyte subpopulations in prostate cancer patients

BACKGROUND

Radiotherapy (RT) is an established treatment for patients with primary and recurrent prostate cancer. Herein, the effects of definitive and salvage RT on the composition of lymphocyte subpopulations were investigated in patients with prostate cancer to study potential immune effects.

PATIENTS AND METHODS

A total of 33 prostate cancer patients were treated with definitive (n = 10) or salvage RT (n = 23) after biochemical relapse. The absolute number of lymphocytes and the distribution of lymphocyte subpopulations were analyzed by multiparameter flow cytometry before RT, at the end of RT, and in the follow-up period.

RESULTS

Absolute lymphocyte counts decreased significantly after RT in both patient groups and a significant drop was observed in the percentage of B cells directly after RT from 10.1 ± 1.3 to 6.0 ± 0.7% in patients with definitive RT and from 9.2 ± 0.8 to 5.8 ± 0.7% in patients with salvage RT. In contrast, the percentages of T and natural killer (NK) cells remained unaltered directly after RT in both patient groups. However, 1 year after RT, the percentage of CD3⁺ T cells was significantly lower in patients with definitive and salvage RT. The percentage of regulatory T cells was slightly upregulated in primary prostate cancer patients after definitive RT, but not after salvage RT.

CONCLUSION

Definitive and salvage RT exert similar effects on the composition of lymphocyte subpopulations in prostate cancer patients. Total lymphocyte counts are lower in both patient groups compared to healthy controls and further decreased after RT. B cells are more sensitive to definitive and salvage RT than T and NK cells.

Fatigue and other adverse effects in men treated by pelvic radiation and long-term androgen deprivation for locally advanced prostate cancer

Background We compared the development of adverse effects and psychosocial measures from baseline to 36-month follow-up in patients with prostate cancer (T1-3 M0) referred to our department for definitive radiotherapy encompassing the prostate and pelvic lymph nodes (RAD + IMRT) or radiotherapy to the prostatic gland only (RAD), applied with standard adjuvant androgen deprivation (AD) in all patients. Few studies have explored the impact of fatigue on patients' reported quality of life (QoL) after combined therapy for prostate cancer. Material and methods The 206 consecutive eligible men (RAD + IMRT = 64 and RAD = 142) completed the UCLA-PCI questionnaire for adverse effects at baseline, 12, 24, and 36 months. QoL, anxiety and depression, and fatigue were rated at the same time points. Between-group and longitudinal within-group changes at different time points were reported. At 36 months variables associated with fatigue were analyzed with regression analyses. Results Our main novel finding is the long-term high level of fatigue and high prevalence of chronic fatigue, affecting patients receiving radiotherapy combined with long-term AD. Except for urinary bother in the RAD + IMRT group all functions and the other bothers mean scores were significantly worse at 36 months compared to baseline. In multivariable analyses only physical QoL remained significantly associated with fatigue at 36-months follow-up. Conclusions Fatigue and impaired QoL in patients considered to curative irradiation with long-term AD should be addressed when counseling men to combined treatment.

No increase in toxicity of pelvic irradiation when intensity modulation is employed: clinical and dosimetric data of 208 patients treated with post-prostatectomy radiotherapy

OBJECTIVE

To compare the toxicity of image-guided intensity-modulated radiotherapy (IG-IMRT) to the pelvis or prostate bed (PB) only. To test the hypothesis that the potentially injurious effect of pelvic irradiation can be counterbalanced by reduced irradiated normal tissue volume using IG-IMRT.

METHODS

Between February 2010 and February 2012, 208 patients with prostate cancer were treated with adjuvant or salvage IG-IMRT to the PB (102 patients, Group PB) or the pelvis and prostate bed (P) (106 patients, Group P). The Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer criteria were used to evaluate toxicity.

RESULTS

Median follow-up was 27 months. Toxicity G ≥ 2 in Group PB: in the bowel acute and late toxicities were 11.8% and 10%, respectively; urinary acute and late toxicities were 10.8% and 15%, respectively. Toxicity G ≥ 2 in Group P: in the bowel acute and late toxicities were both 13.2%; urinary acute and late toxicities were 13.2% and 15.1%, respectively. No statistical difference in acute or late toxicity between the groups was found (bowel: p = 0.23 and p = 0.89 for acute and late toxicity, respectively; urinary: p = 0.39 and p = 0.66 for acute and late toxicity, respectively). Of the clinical variables, only previous abdominal surgery was correlated with acute bowel toxicity. Dosimetric parameters that correlated with bowel toxicity were identified.

CONCLUSION

The toxicity rates were low and similar in both groups, suggesting that IG-IMRT allows for a safe post-operative irradiation of larger volumes. Further investigation is warranted to exclude bias owing to non-randomized character of the study.

ADVANCES IN KNOWLEDGE

Our report shows that modern radiotherapy technology and careful planning allow maintaining the toxicity of pelvic lymph node treatment at the acceptable level, as it is in the case of PB radiotherapy.

Erectile function following brachytherapy, external beam radiotherapy, or radical prostatectomy in prostate cancer patients

BACKGROUND AND PURPOSE

For localized prostate cancer, treatment options include external beam radiotherapy (EBRT), radical prostatectomy (RP), and brachytherapy (BT). Erectile dysfunction (ED) is a common side-effect. Our aim was to evaluate penile erectile function (EF) before and after BT, EBRT, or RP using a validated self-administered quality-of-life survey from a prospective registry.

MATERIAL AND METHODS

Analysis included 478 patients undergoing RP (n = 252), EBRT (n = 91), and BT (n = 135) with at least 1 year of follow-up and EF documented using IIEF-5 scores at baseline, 6 weeks, 6 months, 1 year, and annually thereafter.

RESULTS

Differences among treatments were most pronounced among patients with no or mild initial ED (IIEF-5 ≥ 17). Overall, corrected for baseline EF and age, BT was associated with higher IIEF-5 scores than RP (+ 7.8 IIEF-5 score) or EBRT (+ 3.1 IIEF-5 score). EBRT was associated with better IIEF-5 scores than RP (+ 4.7 IIEF-5 score). In patients undergoing EBRT or RP with bilateral nerve sparing (NS), recovery of EF was observed and during follow-up, the differences to BT were not statistically significant. Overall age had a negative impact on EF preservation (corrected for baseline IIEF).

CONCLUSION

In our series, EF was adversely affected by each treatment modality. Considered overall, BT provided the best EF preservation in comparison to EBRT or RP.

Current role of spacers for prostate cancer radiotherapy

Radiotherapy is an established curative treatment method for prostate cancer. Optimal tumor control rates can only be achieved with high local doses, associated with a considerable risk of rectal toxicity. Apart from already widely adapted technical advances, as intensity-modulated radiation therapy, the application of spacers placed between the prostate and rectum has been increasingly used in the last years. Biodegradable spacers, including hydrogel, hyaluronic acid, collagen or an implantable balloon, can be injected or inserted in a short procedure under transrectal ultrasound guidance via a transperineal approach. A distance of about 1.0-1.5 cm is usually achieved between the rectum and prostate, excluding the rectal wall from the high isodoses. Several studies have shown well tolerated injection procedures and treatments. Apart from considerable reduction of rectal irradiation, a prospective randomized trial demonstrated a reduction of rectal toxicity after hydrogel injection in men undergoing prostate image-guided intensity-modulated radiation therapy. The results are encouraging for continuing evaluation in dose escalation, hypofractionation, stereotactic radiotherapy or re-irradiation trials in the future.

Preliminary patient-reported outcomes analysis of 3-dimensional radiation therapy versus intensity-modulated radiation therapy on the high-dose arm of the Radiation Therapy Oncology Group (RTOG) 0126 prostate cancer trial

BACKGROUND

The authors analyzed a preliminary report of patient-reported outcomes (PROs) among men who received high-dose radiation therapy (RT) on Radiation Therapy Oncology Group study 0126 (a phase 3 dose-escalation trial) with either 3-dimensional conformal RT (3D-CRT) or intensity-modulated RT (IMRT).

METHODS

Patients in the 3D-CRT group received 55.8 gray (Gy) to the prostate and proximal seminal vesicles and were allowed an optional field reduction; then, they received 23.4 Gy to the prostate only. Patients in the IMRT group received 79.2 Gy to the prostate and proximal seminal vesicles. PROs were assessed at 0 months (baseline), 3 months, 6 months, 12 months, and 24 months and included bladder and bowel function assessed with the Functional Alterations due to Changes in Elimination (FACE) instrument and erectile function assessed with the International Index of Erectile Function (IIEF). Analyses included the patients who completed all data at baseline and for at least 1 follow-up assessment, and the results were compared with an imputed data set.

RESULTS

Of 763 patients who were randomized to the 79.2-Gy arm, 551 patients and 595 patients who responded to the FACE instrument and 505 patients and 577 patients who responded to the IIEF were included in the completed and imputed analyses, respectively. There were no significant differences between modalities for any of the FACE or IIEF subscale scores or total scores at any time point for either the completed data set or the imputed data set.

CONCLUSIONS

Despite significant reductions in dose and volume to normal structures using IMRT, this robust analysis of 3D-CRT and IMRT demonstrated no difference in patient-reported bowel, bladder, or sexual functions for similar doses delivered to the prostate and proximal seminal vesicles with IMRT compared with 3D-CRT delivered either to the prostate and proximal seminal vesicles or to the prostate alone.

Spacer application for prostate cancer radiation therapy

Definitive radiotherapy is a well-recognized treatment option for localized prostate cancer. Rectum toxicity is the dose-limiting toxicity. Dose-volume correlations have been reported in many studies. The application of a spacer to increase the distance between the prostate and anterior rectal wall is an innovative technique, considerably reducing the dose to the rectum. Hyaluronic acid, human collagen, an inflatable balloon or hydrogel are potential materials to create the desired effect. The number of clinical studies is rapidly increasing. Well-tolerated injection or implantation techniques and low rectal treatment-related toxicity have been demonstrated in prospective studies. Long-term clinical results and the results of randomized studies are needed to better define the beneficial effect for the patient.

Hypofractionated radiotherapy for prostate cancer

In the last few years, hypofractionated external beam radiotherapy has gained increasing popularity for prostate cancer treatment, since sufficient evidence exists that prostate cancer has a low α/β ratio, lower than the one of the surrounding organs at risk and thus there is a potential therapeutic benefit of using larger fractionated single doses. Apart from the therapeutic rationale there are advantages such as saving treatment time and medical resources and thereby improving patient’s convenience. While older trials showed unsatisfactory results in both standard and hypofractionated arm due to insufficient radiation doses and non-standard contouring of target volumes, contemporary randomized studies have reported on encouraging results of tumor control mostly without an increase of relevant side effects, especially late toxicity. Aim of this review is to give a detailed analysis of relevant, recently published clinical trials with special focus on rationale for hypofractionation and different therapy settings.

Application of a hydrogel spacer for postoperative salvage radiotherapy of prostate cancer

BACKGROUND

In contrast to primary radiotherapy, no reports are available for a hydrogel spacer application in postoperative salvage radiotherapy for prostate cancer.

CASE REPORT

A 77-year-old patient presented 20 years after radical prostatectomy with a digitally palpable local recurrence at the urethrovesical anastomosis (PSA 5.5 ng/ml). The hydrogel spacer (10 ml, SpaceOAR™) was injected between the local recurrence and rectal wall under transrectal ultrasound guidance. Treatment planning was performed with an intensity-modulated technique up to a total dose of 76 Gy in 2-Gy fractions. The same planning was performed based on computed tomography before spacer injection for comparison.

RESULTS

The local recurrence, initially directly on the rectal wall, could be displaced more than  1 cm from the rectal wall after hydrogel injection. With a mean total dose of 76 Gy to the planning target volume, rectal wall volumes included in the 70 Gy, 60 Gy, 50 Gy isodoses were 0 cm(3), 0 cm(3), and 0.4 cm(3) with a spacer and 2.9 cm(3), 4.5 cm(3), and 6.2 cm(3) without a spacer, respectively. The patient reported rectal urgency during radiotherapy, completely resolving after the end of treatment. The PSA level was 5.4 ng/ml a week before the end of radiotherapy and dropped to 0.9 ng/ml 5 months after radiotherapy.

CONCLUSION

A hydrogel spacer was successfully applied for dose-escalated radiotherapy in a patient with macroscopic local prostate cancer recurrence at the urethrovesical anastomosis to decrease the dose at the rectal wall. This option can be considered in specifically selected patients.

Adding intensity-modulated radiotherapy to the pelvis does not worsen the adverse effect profiles compared to limited field radiotherapy in men with prostate cancer at 12-month follow-up

To compare adverse effects and toxicity in men with high-risk or locally advanced prostate cancer when adding intensity-modulated radiotherapy (IMRT) technique to the pelvis.

PATIENTS AND METHODS

In this prospective follow-up study 180 patients treated with conformal radiotherapy (RAD) to the prostate and vesiculae seminales (boost volumes; PV) and long-term androgen deprivation therapy (LADT), were compared to 90 patients managed by LADT, RAD to the PV and additionally pelvic IMRT. Adverse effects were self-reported at baseline, at 3- and 12-month follow-up. At each time point, the patients rated a questionnaire covering urinary, bowel, and sexual function and bother, quality of life, fatigue, and mental distress.

RESULTS

At 3-month follow-up urinary and bowel functions were significantly decreased among IMRT compared to RAD. At 12-month follow-up both groups showed the same reductions within the urinary, bowel and sexual domains. RAD patients had more mental distress than IMRT patients. The scores on quality of life, fatigue and mental distress hardly influenced function or bother within the urinary, bowel or sexual domains.

CONCLUSIONS

Men treated for high-risk or locally advanced prostate cancer with a combination of LADT, RAD and IMRT including PV and pelvic structures had considerably more acute side effects at 3 months than men treated with LADT and RAD to the PV only. However, at 12-month follow-up, the observed genitourinary and gastrointestinal function and bother were similar in both groups.

[Use of hydrogel as spacer in Denovier's space: optimization of IMRT radiotherapy of localized prostate cancer]

BACKGROUND

Radiotherapy is an appropriate primary therapy for localized prostate cancer in accordance with urological guidelines. Especially in tumors of higher grade malignancy, dose escalation up to 80,0 Gy seems to be an advantage; however rectum toxicity can be a problem. By injecting a synthetic hydrogel (SpaceOAR®) as a spacer between the prostate and rectum, rectal toxicity can be reduced. We report on our experiences with 47 patients and an average follow-up of 241 days.

METHODS

From February 2012 to November 2012, 47 patients were included in the study series. Before external radiotherapy the hydrogel was injected between prostate and rectum in the so-called Denovier space. This interdisciplinary procedure was carried out with the patient under general anesthesia using transrectal ultrasound guidance and video documentation. The patients were hospitalized for 1 day. The exact position of the gel was assessed by means of magnetic resonance imaging (MRI). Radiotherapy was initiated 7-14 days after gel application in a dose escalation manner by means of intensity modulated radiation therapy (IMRT) up to a dose of 80,0 Gy. Average follow-up was 241 (100-386, SD 91) days.

RESULTS

No early side effects specific for the application were observed. The achieved distance between rectum and the mid-plane of the prostate gland was on average 13.8 (6-24, SD=3.8) mm. Calculated V70 (rectal volume irradiated with 70.0 Gy or more) could be reduced to an average of 1.5 (0-8, SD=1.7) %. One patient showed an asymptomatic lesion of the rectal mucosa after irradiation with 38,0 Gy. This lesion was closely controlled and gel penetration was found. As a result radiotherapy was discontinued. Without further treatment the necrosis had completely healed 3 months later.

CONCLUSIONS

Hydrogel application between prostate and rectum allows dose escalation up to 80,0 Gy and seems to reduce morbidity in patients with localized prostate cancer receiving radiotherapy. However, before final judgement of the new technique further studies must follow.

Transurethral resection of the prostate after radiotherapy for prostate cancer: impact on quality of life

OBJECTIVES

To evaluate the impact of transurethral resection of the prostate on quality of life after radiotherapy for prostate cancer.

METHODS

A group of 49 consecutive patients with and 487 without prior transurethral resection of the prostate responded to the Expanded Prostate Cancer Index Composite questionnaire before, on the last day, and a median time of 2 months and 16 months after external beam radiotherapy (70-78 Gy). A matched-pair analysis was used to avoid the influence of treatment-associated confounding factors, including dose, treatment volume and hormonal therapy.

RESULTS

Significantly smaller acute urinary score changes relative to baseline levels resulted with versus without prior transurethral resection of the prostate (mean function/bother score decrease of 3/6 vs 18/21 points at the end of radiotherapy; P < 0.01), affecting urinary incontinence (pads to control urinary leakage in 4% vs 24%; P = 0.03) and irritative/obstructive symptoms (big/moderate problem with weak urinary stream in 11% vs 37%; P = 0.02). As opposed to acute changes, transurethral resection of the prostate was a significant predisposing factor for a long-term urinary function score decrease >10 points (20% vs 6% of patients with vs without prior resection; P = 0.04). Urinary incontinence risk was higher for patients with a longer time from resection to radiotherapy.

CONCLUSIONS

Transurethral resection of the prostate significantly affects acute (considerably fewer symptoms) and long-term (relevant toxicity in some cases) urinary quality of life after radiotherapy for prostate cancer.

(11)C-Choline PET/CT as a guide to radiation treatment planning of lymph-node relapses in prostate cancer patients

PURPOSE

To evaluate, in prostate cancer (PCa) patients the potential of (11)C-choline PET/CT as a guide to helical tomotherapy (HTT) of lymph-node (LN) relapses with simultaneous integrated boost (SIB). The efficacy and feasibility of HTT in terms of acute toxicity were assessed.

METHODS

We enrolled 83 PCa patients (mean age 68 years, range 51 - 82 years) with biochemical recurrence after radical primary treatment (mean serum PSA 7.61 ng/ml, range 0.37 - 187.00 ng/ml; PSA0) who showed pathological findings on (11)C-choline PET/CT only at the LN site. (11)C-Choline PET/CT was performed for restaging and then for radiation treatment planning (PET/CT0). Of the 83 patients, 8 experienced further LN relapse, of whom 5 were retreated once and 3 were retreated twice (total 94 radiotherapy treatments). All pelvic and/or abdominal LNs positive on PET/CT0 were treated with high doses using SIB. Doses were in the range 36 - 74 Gy administered in 28 fractions. After the end of HTT (mean 83 days, range 16 - 365 days), serum PSA was measured in all patients (PSA1) and compared with PSA0 to evaluate early biochemical response. In 47 patients PET/CT was repeated (PET/CT1) to assess metabolic responses at the treated areas. Toxicity criteria of the Radiation Therapy Oncology Group (RTOG) were used to assess acute toxicity.

RESULTS

PET/CT0 revealed pathological LNs in the pelvis in 49 patients, pathological LNs in the abdomen in 15 patients pathological LNs in both the pelvis and abdomen in 18 patients, and pathological LNs in the pelvis or abdomen and other sites in 12 patients. All these sites were treated with HTT. With respect to PSA0, PSA1 (mean 6.28 ng/ml, range 0.00 - 220.46 ng/ml) showed a complete biochemical response after 66 of the 94 HTT treatments, a partial response after 12 treatments, stable disease after 1 treatment and progression of disease after 15 treatments. Of the 47 patients receiving PET/CT1, 20 showed a complete metabolic response at the treated area, 22 a partial metabolic response, 3 progression of disease and 2 stable disease. HTT with SIB was well tolerated in all patients. Grade 3 acute toxicity in the genitourinary tract was observed in two patients.

CONCLUSION

(11)C-Choline PET/CT is a valuable tool for planning and monitoring HTT in LN relapse after primary treatment. High-dose hypofractionated (11)C-choline PET/CT-guided HTT with SIB is well tolerated and is associated with a high early biochemical response rate.

Treatment planning after hydrogel injection during radiotherapy of prostate cancer

PURPOSE

Imaging for treatment planning shortly after hydrogel injection is optimal for practical purposes, reducing the number of appointments. The aim was to evaluate the actual difference between early and late imaging.

PATIENTS AND METHODS

Treatment planning computed tomography (CT) was performed shortly after injection of 10 ml hydrogel (CT1) and 1-2 weeks later (CT2) for 3 patients. The hydrogel was injected via the transperineal approach after dissecting the space between the prostate and rectum with a saline/lidocaine solution of at least 20-ml. Hydrogel volume and distances between the prostate and rectal wall were compared. Intensity-modulated radiotherapy (IMRT) plans up to a dose of 78 Gy were generated (rectum V70 < 20 %, rectum V50 < 50 %; with the rectum including hydrogel volume for planning).

RESULTS

A mean planning treatment volume of 104 cm(3) resulted for a prostate volume of 37 cm(3). Hydrogel volumes of 30 and 10 cm(3) were determined in CT1 and CT2, respectively. Distances between the prostate and rectal wall at the levels of the base, middle, and apex were 1.7 cm, 1.6 cm, 1.5 cm in CT1 and 1.3 cm, 1.2 cm, 0.8 cm in CT2, respectively, corresponding to a mean decrease of 24, 25, and 47 %. A small overlap between the PTV and the rectum was found only in 1 patient in CT2 (0.2 cm(3)). The resulting mean rectum (without hydrogel) V75, V70, V60, V50 increased from 0 %, 0 %, 0.6 %, 10 % in CT1 to 0.1 %, 1.2 %, 6 %, 20 % in CT2, respectively.

CONCLUSION

Treatment planning based on imaging shortly after hydrogel injection overestimates the actual hydrogel volume during the treatment as a result of not-yet-absorbed saline solution and air bubbles.

Intensity-modulated radiotherapy to the pelvis and androgen deprivation in men with locally advanced prostate cancer: a study of adverse effects and their relation to quality of life

BACKGROUND

To study, adverse effects, quality of life (QoL), fatigue, and mental distress when intensity-modulated radiotherapy combined with androgen deprivation was applied to the whole pelvis as management of men with locally advanced prostate cancer.

METHODS

In this prospective follow-up study 91 patients were treated by modern pelvic intensity-modulated radiotherapy and followed for 12 months. The patients completed a questionnaire with well-established instruments for adverse effects on urinary, bowel, and sexual function and bother, QoL, fatigue, and mental distress before treatment, and at 3 and 12 months follow-up.

RESULTS

After pelvic intensity-modulated radiotherapy the mean levels of sexual urinary and bowel function and bother were significantly reduced from baseline. Only urinary bother improved from 3 to 12-month follow-up. The levels of fatigue and QoL increased significantly from baseline to 3-month. Mental distress, fatigue, and QoL were significantly associated with both urinary and bowel function and bother at most time points, while so was not observed for sexual bother and function.

CONCLUSIONS

Men treated with pelvic intensity-modulated radiotherapy and androgen deprivation have significant reductions of all types of function and bother at 3 months, with minimal improvement to 12 months except for urinary bother. Fatigue possibly due to pelvic intensity-modulated radiotherapy increased at follow-ups.

Evaluation of different fiducial markers for image-guided radiotherapy and particle therapy

Modern radiotherapy (RT) techniques are widely used in the irradiation of moving organs. A crucial step in ensuring the correct position of a target structure directly before or during treatment is daily image guidance by computed tomography (CT) or X-ray radiography (image-guided radiotherapy, IGRT). Therefore, combinations of modern irradiation devices and imaging, such as on-board imaging (OBI) with X-rays, or in-room CT such as the tomotherapy system, have been developed. Moreover, combinations of linear accelerators and in-room CT-scanners have been designed. IGRT is of special interest in hypofractionated and radiosurgical treatments where high single doses are applied in the proximity of critical organs at risk. Radiographically visible markers in or in close proximity to the target structure may help to reproduce the position during RT and could therefore be used as external surrogates for motion monitoring. Criteria sought for fiducial markers are (i) visibility in the radiologic modalities involved in radiotherapeutic treatment planning and image guidance, such as CT and kilovoltage (kV) OBI), (ii) low production of imaging artifacts, and (iii) low perturbation of the therapeutic dose to the target volume. Photon interaction with interstitial markers has been shown to be not as important as in particle therapy, where interaction of the particle beam, especially with metal markers, can have a significant impact on treatment. This applies especially with a scanned ion beam. Recently we commenced patient recruitment at our institution within the PROMETHEUS trial, which evaluates a hypofractionation regime, starting with 4 x 10 Gy (RBE), for patients with hepatocellular carcinoma. The aim of this work is, therefore, to evaluate potential implantable fiducial markers for enabling precise patient and thus organ positioning in scanned ion beams. To transfer existing knowledge of marker application from photon to particle therapy, we used a range of commercially available markers of different forms and sizes, consisting of carbon and gold materials, and evaluated them for their potential use in the clinical setup with scanned ion beams at our institution. All markers were implanted in a standardized Alderson phantom and were examined using CT scans and orthogonal kV OBI in our clinical routine protocol. Impact on beam perturbation downstream of the markers in the plateau region of a spread-out Bragg peak (SOBP) was estimated by using radiographic films for clinical proton and carbon ion beams of high and low energies. All tested markers achieved good visibility in CT and kV OBI. Disturbances due to artifacts and dose perturbation were highest in the arbitrarily folded gold and the thickest gold marker, but especially low in the carbon marker. Dose perturbation was highest in the arbitrarily folded gold marker. In summary, the analyzed markers offer promising potential for identifying target structures in our treatment setup at HIT and will soon be used in clinical routine. However, a careful choice of marker, depending on the tumor localization and irradiation strategy, will need to be made.

Current standards and future directions for prostate cancer radiation therapy

Definitive radiation therapy is a well-recognized curative treatment option for localized prostate cancer. A suitable technique, dose, target volume and the option of a combination with androgen deprivation therapy need to be considered. An optimal standard external beam radiotherapy currently includes intensity-modulated and image-guided radiotherapy techniques with total doses of ≥76-78 Gy in conventional fractionation. Protons or carbon ions are alternatives available only in specific centers. Data from several randomized studies increasingly support the rationale for hypofractionated radiotherapy. A simultaneous integrated boost with dose escalation focused on a computed tomography/PET- or MRI/magnetic resonance spectroscopy-detected malignant lesion is one option to increase tumor control, with potentially no additional toxicity. The application of a spacer is a promising concept for optimal protection of the rectal wall.

Reducing rectal injury during external beam radiotherapy for prostate cancer

Rectal bleeding and faecal incontinence are serious injuries that men with prostate cancer who receive radiotherapy can experience. Although technical advances--including the use of intensity-modulated radiotherapy coupled with image-guided radiotherapy--have enabled the delivery of dose distributions that conform to the shape of the tumour target with steep dose gradients that reduce the dose given to surrounding tissues, radiotherapy-associated toxicity can not be avoided completely. Many large-scale prospective studies have analysed the correlations of patient-related and treatment-related parameters with acute and late toxicity to optimize patient selection and treatment planning. The careful application of dose-volume constraints and the tuning of these constraints to the individual patient's characteristics are now considered the most effective ways of reducing rectal morbidity. Additionally, the use of endorectal balloons (to reduce the margins between the clinical target volume and planning target volume) and the insertion of tissue spacers into the region between the prostate and anterior rectal wall have been investigated as means to further reduce late rectal injury. Finally, some drugs and other compounds are also being considered to help protect healthy tissue. Overall, a number of approaches exist that must be fully explored in large prospective trials to address the important issue of rectal toxicity in prostate cancer radiotherapy.

Pelvic Ewing sarcomas. Three-dimensional conformal vs. intensity-modulated radiotherapy

PURPOSE

The goal of the present work was to assess the potential advantage of intensity-modulated radiotherapy (IMRT) over three-dimensional conformal radiotherapy (3D-CRT) planning in pelvic Ewing's sarcoma.

PATIENTS AND METHODS

A total of 8 patients with Ewing sarcoma of the pelvis undergoing radiotherapy were analyzed. Plans for 3D-CRT and IMRT were calculated for each patient. Dose coverage of the planning target volume (PTV), conformity and homogeneity indices, as well as further parameters were evaluated.

RESULTS

The average dose coverage values for PTV were comparable in 3D-CRT and IMRT plans. Both techniques had a PTV coverage of V95 > 98 % in all patients. Whereas the IMRT plans achieved a higher conformity index compared to the 3D-CRT plans (conformity index 0.79 ± 0.12 vs. 0.54 ± 0.19, p = 0.012), the dose distribution across the target volumes was less homogeneous with IMRT planning than with 3D-CRT planning. This difference was statistically significant (homogeneity index 0.11 ± 0.03 vs. 0.07 ± 0.0, p = 0.035). For the bowel, Dmean and D1%, as well as V2 to V60 were reduced in IMRT plans. For the bladder and the rectum, there was no significant difference in Dmean. However, the percentages of volumes receiving at least doses of 30, 40, 45, and 50 Gy (V30 to V50) were lower for the rectum in IMRT plans. The volume of normal tissue receiving at least 2 Gy (V2) was significantly higher in IMRT plans compared with 3D-CRT, whereas at high dose levels (V30) it was significantly lower.

CONCLUSION

Compared to 3D-CRT, IMRT showed significantly better results regarding dose conformity (p = 0.012) and bowel sparing at dose levels above 30 Gy (p = 0.012). Thus, dose escalation in the radiotherapy of pelvic Ewing's sarcoma can be more easily achieved using IMRT.

Prospective evaluation of a hydrogel spacer for rectal separation in dose-escalated intensity-modulated radiotherapy for clinically localized prostate cancer

BACKGROUND

As dose-escalation in prostate cancer radiotherapy improves cure rates, a major concern is rectal toxicity. We prospectively assessed an innovative approach of hydrogel injection between prostate and rectum to reduce the radiation dose to the rectum and thus side effects in dose-escalated prostate radiotherapy.

METHODS

Acute toxicity and planning parameters were prospectively evaluated in patients with T1-2 N0 M0 prostate cancer receiving dose-escalated radiotherapy after injection of a hydrogel spacer. Before and after hydrogel injection, we performed MRI scans for anatomical assessment of rectal separation. Radiotherapy was planned and administered to 78 Gy in 39 fractions.

RESULTS

From eleven patients scheduled for spacer injection the procedure could be performed in ten. In one patient hydrodissection of the Denonvillier space was not possible. Radiation treatment planning showed low rectal doses despite dose-escalation to the target. In accordance with this, acute rectal toxicity was mild without grade 2 events and there was complete resolution within four to twelve weeks.

CONCLUSIONS

This prospective study suggests that hydrogel injection is feasible and may prevent rectal toxicity in dose-escalated radiotherapy of prostate cancer. Further evaluation is necessary including the definition of patients who might benefit from this approach.

TRIAL REGISTRATION

German Clinical Trials Register DRKS00003273.

Spacer stability and prostate position variability during radiotherapy for prostate cancer applying a hydrogel to protect the rectal wall

BACKGROUND AND PURPOSE

The aim was to evaluate the spacer dimensions and prostate position variability during the course of radiotherapy for prostate cancer.

MATERIALS AND METHODS

CT scans were performed in a group of 15 patients (G1) after the 10 ml injection of a hydrogel spacer (SpaceOAR™) and 30 patients without a spacer (G2) before the beginning of treatment (CT1) and in the last treatment week, 10-12 weeks following spacer implantation (CT2). Spacer dimensions and displacements were determined and prostate displacements compared.

RESULTS

Mean volume of the hydrogel increased slightly (17%; p<0.01), in 4 of 15 patients >2 cm(3). The average displacement of the hydrogel center of mass was 0.6mm (87%≤ 2.2mm), -0.6mm (100% ≤ 2.2mm) and 1.4mm (87% ≤ 4.3mm) in the x-, y- and z-axes (not significant). The average distance between prostate and anterior rectal wall before/at the end of radiotherapy was 1.6 cm/1.5 cm, 1.2 cm/1.3 cm and 1.0 cm/1.1cm at the level of the base, middle and apex (G1). Prostate position variations were similar comparing G1 and G2, but significant systematic posterior displacements were only found in G2.

CONCLUSIONS

A stable distance between the prostate and anterior rectal wall results during the radiotherapy course after injection of the spacer before treatment planning. Larger posterior prostate displacements could be reduced.

Erectile dysfunction after prostate three-dimensional conformal radiation therapy. Correlation with the dose to the penile bulb

PURPOSE

Erectile dysfunction is associated with all the common treatment options for prostate cancer. The aim of this research was to evaluate the relationship between erectile function and radiation dose to the penile bulb (PB) and other proximal penile structures in men receiving conformal radiotherapy (CRT) without hormonal therapy (HT) for prostate cancer, whose sexual function was known before treatment.

PATIENTS AND METHODS

The study included 19 patients treated with 3D-CRT for localized prostate cancer at our department, who were self-reported to be potent before treatment, had not received HT, and had complete follow-up data available. Our evaluation was based on the International Index of Erectile Function (IIEF-5). Dose-volume histograms (DVHs) were used to evaluate the dose to the PB. Statistical analysis was performed with an unconditional logistic regression model.

RESULTS

All patients reported change in potency after radiation. Eight patients (42%) remained potent but showed a decrease of 1 or 2 levels of potency, as defined by the IIEF-5 questionnaire (reduced potency group), while 11 patients (58%) reported a change of higher levels and revealed a severe erectile dysfunction after 2 years (impotence group). Multivariate analysis of morphological and dosimetric variables yielded significance for the mean dose (p = 0.05 with an odds ratio of 1.14 and 95% CI 1-1.30). Patients receiving a mean dose of less than 50 Gy to the PB appear to have a much greater likelihood of maintaining potency.

CONCLUSION

Our data suggest a possible existence of a dose-volume correlation between the dose applied to the PB and radiation-induced impotence.

Quality of life after intensity-modulated radiotherapy for prostate cancer with a hydrogel spacer. Matched-pair analysis

BACKGROUND

Hydrogel spacer is an innovative method to protect the rectal wall during prostate cancer radiotherapy. Clinical effects are not well known.

METHODS

Patients have been surveyed before, at the last day, and 2-3 months after radiotherapy using a validated questionnaire (Expanded Prostate Cancer Index Composite). Median dose to the prostate in the spacer subgroup (SP) was 78 Gy in 2 Gy fractions. The results were independently compared with two matched-pair subgroups (treated conventionally without spacer): 3D conformal 70.2 Gy in 1.8 Gy fractions (3DCRT) and intensity-modulated radiotherapy (IMRT) 76 Gy in 2 Gy fractions. There were 28 patients in each of the three groups.

RESULTS

Baseline mean bowel bother scores were 96 points in all subgroups. Similar mean changes (SP 16, 3DCRT 14, IMRT 17 points) were observed at the end of radiotherapy. The smallest difference resulted in the spacer subgroup 2-3 months after radiotherapy (SP 2, 3DCRT 8, IMRT 6 points). Bowel bother scores were only significantly different in comparison to baseline levels in the spacer subgroup. The percentage of patients reporting moderate/big bother with specific symptoms did not increase for any item (urgency, frequency, diarrhoea, incontinence, bloody stools, pain).

CONCLUSION

Moderate bowel quality-of-life changes can be expected during radiotherapy irrespective of spacer application or total dose. Advantages with a spacer can be expected a few weeks after treatment.

Highly cited German research contributions to the fields of radiation oncology, biology, and physics: focus on collaboration and diversity

BACKGROUND AND PURPOSE

Tight budgets and increasing competition for research funding pose challenges for highly specialized medical disciplines such as radiation oncology. Therefore, a systematic review was performed of successfully completed research that had a high impact on clinical practice. These data might be helpful when preparing new projects.

METHODS

Different measures of impact, visibility, and quality of published research are available, each with its own pros and cons. For this study, the article citation rate was chosen (minimum 15 citations per year on average). Highly cited German contributions to the fields of radiation oncology, biology, and physics (published between 1990 and 2010) were identified from the Scopus database.

RESULTS

Between 1990 and 2010, 106 articles published in 44 scientific journals met the citation requirement. The median average of yearly citations was 21 (maximum 167, minimum 15). All articles with ≥ 40 citations per year were published between 2003 and 2009, consistent with the assumption that the citation rate gradually increases for up to 2 years after publication. Most citations per year were recorded for meta-analyses and randomized phase III trials, which typically were performed by collaborative groups.

CONCLUSION

A large variety of clinical radiotherapy, biology, and physics topics achieved high numbers of citations. However, areas such as quality of life and side effects, palliative radiotherapy, and radiotherapy for nonmalignant disorders were underrepresented. Efforts to increase their visibility might be warranted.

Assessment of accuracy and efficiency of atlas-based autosegmentation for prostate radiotherapy in a variety of clinical conditions

BACKGROUND AND PURPOSE

The goal of the current study was to evaluate the commercially available atlas-based autosegmentation software for clinical use in prostate radiotherapy. The accuracy was benchmarked against interobserver variability.

MATERIAL AND METHODS

A total of 20 planning computed tomographs (CTs) and 10 cone-beam CTs (CBCTs) were selected for prostate, rectum, and bladder delineation. The images varied regarding to individual (age, body mass index) and setup parameters (contrast agent, rectal balloon, implanted markers). Automatically created contours with ABAS(®) and iPlan(®) were compared to an expert's delineation by calculating the Dice similarity coefficient (DSC) and conformity index.

RESULTS

Demo-atlases of both systems showed different results for bladder (DSC(ABAS) 0.86 ± 0.17, DSC(iPlan) 0.51 ± 0.30) and prostate (DSC(ABAS) 0.71 ± 0.14, DSC(iPlan) 0.57 ± 0.19). Rectum delineation (DSC(ABAS) 0.78 ± 0.11, DSC(iPlan) 0.84 ± 0.08) demonstrated differences between the systems but better correlation of the automatically drawn volumes. ABAS(®) was closest to the interobserver benchmark. Autosegmentation with iPlan(®), ABAS(®) and manual segmentation took 0.5, 4 and 15-20 min, respectively. Automatic contouring on CBCT showed high dependence on image quality (DSC bladder 0.54, rectum 0.42, prostate 0.34).

CONCLUSION

For clinical routine, efforts are still necessary to either redesign algorithms implemented in autosegmentation or to optimize image quality for CBCT to guarantee required accuracy and time savings for adaptive radiotherapy.

Comparison of preoperative short-course radiotherapy and long-course radiochemotherapy for locally advanced rectal cancer

BACKGROUND

The purpose of this work was to perform a single institution comparison between preoperative short-course radiotherapy (SC-RT) and long-course radiochemotherapy (LC-RCHT) for locally advanced rectal cancer.

METHODS

A total of 225 patients with clinical stage UICC II-III rectal cancer were treated with SC-RT (29 Gy in 10 twice daily fractions followed by immediate surgery; n = 108) or LC-RCHT (54 Gy in 28 fractions with simultaneous 5-fluorouracil (5-FU) ± oxaliplatin chemotherapy followed by delayed surgery; n = 117). All patients in the LC-RCHT cohort and patients in the SC-RT with pathological UICC stage ≥ II received adjuvant chemotherapy. Before 2004, the standard of care was SC-RT with LC-RCHT reserved for patients where downstaging was considered as required for sphincter preservation or curative resection. In the later period, SC-RT was practiced only for patients unfit for radiochemotherapy.

RESULTS

Patients in the LC-RCHT cohort had a significantly higher proportion of cT4 tumors, clinical node positivity, and lower tumor location. The 5-year local control (LC) and overall survival (OS) were 91% and 66% without differences between the SC-RT and LC-RCHT groups. Acute toxicity was increased during LC-RCHT (grade ≥ II 1% vs. 33%) and there were no differences in postoperative complications. Severe late toxicity grade ≥ III was increased after SC-RT (12% vs. 3%). Of patients aged >  80 years, 7 of 7 patients and 4 of 9 patients received curative surgery after SC-RT and LC-RCHT, respectively.

CONCLUSION

Despite the fact that patients with worse prognostic factors were treated with LC-RCHT, there were no significant differences in LC and OS between the SC-RT and LC-RCHT group. Age > 80 years was identified as a significant risk factor for LC-RCHT and these patients could be treated preferably with SC-RT.

Patient positioning variations to reduce dose to normal tissues during 3D conformal radiotherapy for high-risk prostate cancer

BACKGROUND AND PURPOSE

The goal of this work was to assess optimal treatment positioning of 3D conformal radiotherapy (3DCRT) for high-risk prostate cancer patients.

PATIENTS AND METHODS

Treatment plans of 25 patients in different patient positions were evaluated: with knee and ankle support (KAS) in the supine position and with a belly board (BB) in the prone position both with full (FB) and empty bladder (EB). Planning target volumes (PTVs) for pelvis, prostate and vesicles, prostate, and organs at risk (OARs) were delineated. Dose and overlapping volumes were evaluated.

RESULTS

Overlapping volumes were significantly smaller with a FB than with an EB. No significant differences were found in overlapping volumes with respect to patient fixation systems, but the percentage values of dose to the OARs showed significantly better results employing KAS than a BB. A FB reduced the dose volumes to the OARs. Comparison with respect to circumference of abdomen (CA) showed significantly smaller overlapping at large CA in most of the cases.

CONCLUSION

Supine position is suggested with KAS combined with a FB (especially in cases of larger CA) when using 3DCRT with planning technique modification for high-risk prostate cancer patients to reduce the dose of OARs, based on our results.

Comparison of seed brachytherapy or external beam radiotherapy (70 Gy or 74 Gy) in 919 low-risk prostate cancer patients

PURPOSE

The aim of this analysis was to compare the biochemical no evidence of disease (bNED) rates in low-risk prostate cancer patients treated at two centers of excellence using different approaches: seed brachytherapy (BT) and external beam radiotherapy (EBRT).

MATERIALS AND METHODS

A total of 919 low-risk prostate cancer patients, treated from 1998-2008, were identified in the two databases. In Utrecht, 667 patients received I-125 BT applying a dose of 144 Gy. In Vienna, 252 patients were treated with EBRT, applying a local dose of 70 Gy in 82 patients and 74 Gy in 170 patients. bNED rates (Phoenix definition) were assessed.

RESULTS

The median follow-up was 46 months (range 1-148 months). The 5-year actuarial bNED rates were 94% for BT patients and 88% for EBRT patients (p = 0.002)-84% for patients receiving 70 Gy and 91% for patients receiving 74 Gy, respectively. In the univariate analysis, patients receiving 70 Gy showed significantly worse outcome compared to BT (p = 0.001) and a difference close to significance compared to 74 Gy (p = 0.06). In the multivariate analysis including tumor stage, Gleason score, initial PSA, hormonal therapy, and dose, patients receiving 70 Gy EBRT showed significantly worse bNED rates compared to BT patients.

CONCLUSION

Low-risk prostate cancer patients receiving 74 Gy by EBRT show comparable biochemical control rates to patients receiving seed brachytherapy, whereas patients receiving 70 Gy show significantly worse outcome.

Risk factors related to interfractional variation in whole pelvic irradiation for locally advanced pelvic malignancies

PURPOSE

The goal of the present study was to demonstrate risk factors affecting the interfractional variation in whole pelvic irradiation.

PATIENTS AND METHODS

Daily image acquisitions of 101 patients with locally advanced pelvic malignancy were undertaken using a kilo-voltage orthogonal on-board imager. The baseline deviation (the shift between the initial treatment and each fraction; Value(Base)) and day-to-day variation (the shift between the previous treatment and each fraction; Value(DD)) were measured. The standard deviations (SD) along the x- (right-left), y- (cranial-caudal), and z- (anterior-posterior) axes (SD[x], SD[y], and SD[z], respectively), the 3D vector of the SD (SD[3D]), and the mean of 3D shift (mean[3D]) were calculated in each patient. Various clinical factors, lumbar pelvic balance and rotation, and the shift of 5 consecutive fractions from the initial treatment (Value(5Fx)) were investigated as risk factors.

RESULTS

The prone set-up showed a larger mean(Base)[3D] than in the supine position (p =0 .063). A body mass index (BMI) ≥ 30 kg/m(2) resulted in the largest mean(DD)[3D] (p = 0.078) and SD(DD)[3D] (p = 0.058). All the SD(5Fx) along the x-, y-, and z-axes had moderate linear relationships with SD(Base) and SD(DD) (p < 0.001). The SD(5Fx)[3D] also had a moderate linear relationship with the mean(Base)[3D], mean(DD)[3D], SD(Base)[3D], and SD(DD)[3D] (p < 0.001). In multivariate analysis, the SD(5Fx) had the same significant relationship with SD(Base) and SD(DD) (p < 0.001). A BMI ≥ 30 kg/m(2) was associated with the largest SD(DD)[x] (p = 0.003).

CONCLUSION

Close surveillance through high-quality and frequent image guidance is recommended for patients with extensive variations of the initial five consecutive fractions or obesity.

Adjuvant intensity-modulated proton therapy in malignant pleural mesothelioma. A comparison with intensity-modulated radiotherapy and a spot size variation assessment

PURPOSE

Intensity-modulated radiation therapy (IMRT) is the state-of-the-art treatment for patients with malignant pleural mesothelioma (MPM). The goal of this work was to assess whether intensity-modulated proton therapy (IMPT) could further improve the dosimetric results allowed by IMRT.

PATIENTS AND METHODS

We re-planned 7 MPM cases using both photons and protons, by carrying out IMRT and IMPT plans. For both techniques, conventional dose comparisons and normal tissue complication probability (NTCP) analysis were performed. In 3 cases, additional IMPT plans were generated with different beam dimensions.

RESULTS

IMPT allowed a slight improvement in target coverage and clear advantages in dose conformity (p < 0.001) and dose homogeneity (p = 0.01). Better organ at risk (OAR) sparing was obtained with IMPT, in particular for the liver (D(mean) reduction of 9.5 Gy, p = 0.001) and ipsilateral kidney (V(20) reduction of 58%, p = 0.001), together with a very large reduction of mean dose for the contralateral lung (0.2 Gy vs 6.1 Gy, p = 0.0001). NTCP values for the liver showed a systematic superiority of IMPT with respect to IMRT for both the esophagus (average NTCP 14% vs. 30.5%) and the ipsilateral kidney (p = 0.001). Concerning plans obtained with different spot dimensions, a slight loss of target coverage was observed along with sigma increase, while maintaining OAR irradiation always under planning constraints.

CONCLUSION

Results suggest that IMPT allows better OAR sparing with respect to IMRT, mainly for the liver, ipsilateral kidney, and contralateral lung. The use of a spot dimension larger than 3 × 3 mm (up to 9 × 9 mm) does not compromise dosimetric results and allows a shorter delivery time.

Critical discussion of evaluation parameters for inter-observer variability in target definition for radiation therapy

BACKGROUND AND PURPOSE

Inter-observer studies represent a valid method for the evaluation of target definition uncertainties and contouring guidelines. However, data from the literature do not yet give clear guidelines for reporting contouring variability. Thus, the purpose of this work was to compare and discuss various methods to determine variability on the basis of clinical cases and a literature review.

PATIENTS AND METHODS

In this study, 7 prostate and 8 lung cases were contoured on CT images by 8 experienced observers. Analysis of variability included descriptive statistics, calculation of overlap measures, and statistical measures of agreement. Cross tables with ratios and correlations were established for overlap parameters.

RESULTS

It was shown that the minimal set of parameters to be reported should include at least one of three volume overlap measures (i.e., generalized conformity index, Jaccard coefficient, or conformation number). High correlation between these parameters and scatter of the results was observed.

CONCLUSION

A combination of descriptive statistics, overlap measure, and statistical measure of agreement or reliability analysis is required to fully report the interrater variability in delineation.

Toxicity and Long-Term Outcomes of Dose-Escalated Intensity Modulated Radiation Therapy to 74Gy for Localised Prostate Cancer in a Single Australian Centre

Purpose

To report the toxicity and long-term outcomes of dose-escalated intensity-modulated radiation therapy (IMRT) for patients with localised prostate cancer.

Methods and Materials

From 2001 to 2005, a total of 125 patients with histologically confirmed T1-3N0M0 prostate cancer were treated with IMRT to 74Gy at the Austin Health Radiation Oncology Centre. The median follow-up was 5.5 years (range 0.5–8.9 years). Biochemical prostate specific antigen (bPSA) failure was defined according to the Phoenix consensus definition (absolute nadir + 2ng/mL). Toxicity was scored according to the RTOG/EORTC criteria. Kaplan-Meier analysis was used to calculate toxicity rates, as well as the risks of bPSA failure, distant metastases, disease-specific and overall survival, at 5 and 8-years post treatment.

Results

All patients completed radiotherapy without any treatment breaks. The 8-year risks of ≥ Grade 2 genitourinary (GU) and gastrointestinal (GI) toxicity were 6.4% and 5.8% respectively, and the 8-year risks of ≥ Grade 3 GU and GI toxicity were both < 0.05%. The 5 and 8-year freedom from bPSA failure were 76% and 58% respectively. Disease-specific survival at 5 and 8 years were 95% and 91%, respectively, and overall survival at 5 and 8 years were 90% and 71%, respectively.

Conclusions

These results confirm existing international data regarding the safety and efficacy of dose-escalated intensity-modulated radiation therapy for localised prostate cancer within an Australian setting.