Victoria Djukic

Application of a spacer gel to optimize three-dimensional conformal and intensity modulated radiotherapy for prostate cancer

BACKGROUND AND PURPOSE The aim was to evaluate the impact of a spacer gel on the dose distribution, applying three-dimensional conformal (3D CRT) and intensity modulated radiotherapy (IMRT) planning techniques. MATERIAL AND METHODS The injection of a spacer gel (10 ml SpaceOAR™) was performed between the prostate and rectum under transrectal ultrasound guidance in 18 patients with prostate cancer. 3D CRT and IMRT treatment plans were compared based on CT before and after injection (78 Gy prescription dose). RESULTS In contrast to the PTV and bladder, significant advantages (p<0.01) resulted in respect of all analysed rectal dose values comparing pre spacer with post spacer plans for both techniques. Rectal NTCP (normal tissue complication probability) reached the lowest percentage after spacer injection irrespective of the technique, with a mean reduction of >50% for both IMRT and 3D CRT. Significantly (p<0.01) higher D(mean), and V(78) for the PTV were reached with IMRT vs. 3D CRT plans, with a smaller rectum V(76) but larger rectum V(50). CONCLUSIONS The injection of a spacer gel between the prostate and anterior rectal wall is associated with considerably lower doses to the rectum and consequentially lower NTCP values irrespective of the radiotherapy technique.

Dose-escalation using intensity-modulated radiotherapy for prostate cancer - evaluation of quality of life with and without 18 F-choline PET-CT detected simultaneous integrated boost

BackgroundIn comparison to the conventional whole-prostate dose escalation, an integrated boost to the macroscopic malignant lesion might potentially improve tumor control rates without increasing toxicity. Quality of life after radiotherapy (RT) with vs. without 18F-choline PET-CT detected simultaneous integrated boost (SIB) was prospectively evaluated in this study.MethodsWhole body image acquisition in supine patient position followed 1 h after injection of 178-355MBq 18F-choline. SIB was defined by a tumor-to-background uptake value ratio > 2 (GTVPET). A dose of 76Gy was prescribed to the prostate (PTVprostate) in 2Gy fractions, with or without SIB up to 80Gy. Patients treated with (n = 46) vs. without (n = 21) SIB were surveyed prospectively before (A), at the last day of RT (B) and a median time of two (C) and 19 month (D) after RT to compare QoL changes applying a validated questionnaire (EPIC - expanded prostate cancer index composite).ResultsWith a median cut-off standard uptake value (SUV) of 3, a median GTVPET of 4.0 cm3 and PTVboost (GTVPET with margins) of 17.3 cm3 was defined. No significant differences were found for patients treated with vs. without SIB regarding urinary and bowel QoL changes at times B, C and D (mean differences ≤3 points for all comparisons). Significantly decreasing acute urinary and bowel score changes (mean changes > 5 points in comparison to baseline level at time A) were found for patients with and without SIB. However, long-term urinary and bowel QoL (time D) did not differ relative to baseline levels - with mean urinary and bowel function score changes < 3 points in both groups (median changes = 0 points). Only sexual function scores decreased significantly (> 5 points) at time D.ConclusionsTreatment planning with 18F-choline PET-CT allows a dose escalation to a macroscopic intraprostatic lesion without significantly increasing toxicity.

Combination of Dose Escalation with Technological Advances (Intensity-Modulated and Image-Guided Radiotherapy) Is Not Associated with Increased Morbidity for Patients with Prostate Cancer

Purpose:The aim was to evaluate treatment-related morbidity after intensity-modulated (IMRT) and image-guided (IGRT) radiotherapy with a total dose of 76 Gy in comparison to conventional conformal radiotherapy (3DCRT) up to 70.2–72 Gy for patients with prostate cancer.Patients and Methods:All patients were prospectively surveyed prior to, on the last day, as well as after a median time of 2 and 16 months after RT using a validated questionnaire (Expanded Prostate Cancer Index Composite). Criteria for the 78 matched pairs after IMRT vs. 3DCRT were patient age, use of antiandrogens, treatment volume (± whole pelvis), prognostic risk group, and urinary/bowel/sexual quality of life (QoL) before treatment.Results:QoL changes after dose-escalated IMRT were found to be similar to QoL changes after 3DCRT in all domains. Only sexual function scores more than 1 year after RT decreased slightly more after 3DCRT in comparison to IMRT (mean 9 vs. 6 points; p = 0.04), with erections firm enough for intercourse in 14% vs. 30% (p = 0.03). Painful bowel movements were reported more frequently after 3DCRT vs. IMRT 2 months after treatment (≥ once a day in 10% vs. 1%; p = 0.03), but a tendency for higher rectal bleeding rates was found after IMRT vs. 3DCRT more than 1 year after RT (≥ rarely in 20% vs. 9%; p = 0.06).Conclusion:Combination of dose escalation with technological advances (IMRT and IGRT) is not associated with increased morbidity for patients with prostate cancer.ZusammenfassungZiel:Ziel war die Analyse therapiebedingter Morbidität nach intensitätsmodulierter (IMRT) und bildgeführter (IGRT) Radiotherapie mit einer Gesamtdosis von 76 Gy im Vergleich zur konventionellen konformalen Radiotherapie (3DCRT) bis 70,2–72 Gy bei Patienten mit einem Prostatakarzinom.Patienten und Methoden:Alle Patienten wurden prospektiv vor Beginn, am letzten Tag, median 2 Monate und 16 Monate nach RT mittels eines validierten Fragebogens befragt (Expanded Prostate Cancer Index Composite). Kriterien für 78 gematchte Paare nach IMRT vs. 3DCRT waren das Patientenalter, der Einsatz eines Antiandrogens, Zielvolumen (± Becken), prognostische Risikogruppe und Lebensqualität (LQ) beim Wasserlassen/Stuhlgang/Sexualität vor der Behandlung.Ergebnisse:LQ-Veränderungen nach dosiseskalierter IMRT waren den LQ-Veränderungen nach 3DCRT in allen Domänen sehr ähnlich. Nur der Punktwert für die sexuelle Funktion fiel über ein Jahr nach der Behandlung nach 3DCRT etwas mehr als nach IMRT (durchschnittlich 9 vs. 6 Punkte; p = 0,04), mit ausreichender Erektion für Geschlechtsverkehr in 14% vs. 30% (p = 0,03). Schmerzhafter Stuhlgang wurde zwei Monate nach Therapie häufiger nach 3DCRT als nach IMRT berichtet (≥ 1-mal täglich in 10% vs. 1%; p = 0,03); jedoch fand sich über ein Jahr nach RT die Tendenz zu einer häufigeren Rate rektaler Blutungen nach IMRT als nach 3DCRT (≥ selten in 20% vs. 9%; p = 0,06).Schlussfolgerung:Die Verknüpfung einer Dosiseskalation mit technologischen Fortschritten (IMRT und IGRT) ist bei Patienten mit einem Prostatakarzinom nicht mit erhöhter Morbidität assoziiert.

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.

Hematologic changes during prostate cancer radiation therapy are dependent on the treatment volume

AIM To assess hematologic changes of modern prostate radiation therapy (RT) comparing different target volumes. PATIENTS & METHODS Blood samples were evaluated before (T1), during (T2-T4) and 6-8 weeks after (T5) RT in a group of 113 patients. Whole-pelvic RT up to 46 Gy was applied in 27 cases. The total dose to the prostatic fossa (n = 46)/prostate (n = 67) was 66/76 Gy. RESULTS Erythrocyte, leukocyte and platelet levels decreased significantly relative to baseline levels at T2-T5. Neoadjuvant hormonal therapy had an impact on hemoglobin levels before and during RT. The cumulative incidence of grade 2 leukopenia was 15 versus 2% (p = 0.02) and grade 2 anemia 8 versus 0% (p = 0.03) with versus without whole-pelvic RT, respectively. Lymphocyte decrease was larger at times T2-T5 (36 vs 3% grade 3 toxicity; p < 0.01). CONCLUSION Prostate RT has a small but significant and longer effect on the blood count. Lower lymphocyte levels need to be considered when larger volumes are treated.

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

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

PO-0669 BOWEL TOXICITY AFTER IMRT FOR PROSTATE CANCER WITH A SPACER GEL – A MATCHED-PAIR COMPARISON

dose. Advantages following radiotherapy with a hydrogel spacer can be expected a few weeks after treatment and presumably in the long term. The application of a hydrogel spacer is an innovative technique to protect the rectal wall during prostate cancer radiotherapy. Clinical effects are not well known. The aim of the study was to compare acute bowel quality of life changes after intensity modulated radiotherapy (IMRT) with a spacer gel in comparison to low and high dose radiotherapy without a spacer gel.

Local prostate cancer radiotherapy after prostate-specific antigen progression during primary hormonal therapy.

BackgroundThe outcome of patients after radiotherapy (RT) for localized prostate cancer in case of prostate-specific antigen (PSA) progression during primary hormonal therapy (HT) is not well known.MethodsA group of 27 patients presenting with PSA progression during primary HT for local prostate cancer RT was identified among patients who were treated in the years 2000–2004 either using external-beam RT (EBRT; 70.2Gy; n=261) or Ir-192 brachytherapy as a boost to EBRT (HDR-BT; 18Gy + 50.4Gy; n=71). The median follow-up period after RT was 68 months.ResultsMedian biochemical recurrence free (BRFS), disease specific (DSS) and overall survival (OS) for patients with PSA progression during primary HT was found to be only 21, 54 and 53 months, respectively, with a 6-year BRFS, DSS and OS of 19%, 41% and 26%. There were no significant differences between different RT concepts (6-year OS of 27% after EBRT and 20% after EBRT with HDR-BT).Considering all 332 patients in multivariate Cox regression analysis, PSA progression during initial HT, Gleason score>6 and patient age were found to be predictive for lower OS (p<0.001). The highest hazard ratio resulted for PSA progression during initial HT (7.2 in comparison to patients without PSA progression during primary HT). PSA progression and a nadir >0.5 ng/ml during initial HT were both significant risk factors for biochemical recurrence.ConclusionsAn unfavourable prognosis after PSA progression during initial HT needs to be considered in the decision process before local prostate radiotherapy. Results from other centres are needed to validate our findings.