CyberKnife versus multicatheter interstitial brachytherapy for accelerated partial breast irradiation: a dosimetrical assessment with focus on organs at risk.

Background: The purpose of the study was to dosimetrically compare multicatheter interstitial brachytherapy (MIBT) and stereotactic radiotherapy with CyberKnife (CK) for accelerated partial breast irradiation with special focus on dose to organs at risk (OARs). Materials and methods: Treatment plans of thirty-one patients treated with MIBT were selected and additional CK plans were created on the same CT images. The OARs included ipsilateral non-target and contralateral breast, ipsilateral and contralateral lung, skin, ribs, and heart for left sided cases. The fractionation was identical (4 × 6.25 Gy). Dose-volume parameters were calculated for both techniques and compared. Results: The D90 of the PTV for MIBT and CK were similar (102.4% vs. 103.6%, p = 0.0654), but in COIN the MIBT achieved lower value (0.75 vs. 0.91, p < 0.001). Regarding the V100 parameter of non-target breast CK performed slightly better than MIBT (V100: 1.1% vs. 1.6%), but for V90, V50 and V25 MIBT resulted in less dose. Every examined parameter of ipsilateral lung, skin, ribs and contralateral lung was significantly smaller for MIBT than for CK. Protection of the heart was slightly better with MIBT, but only the difference of D2cm3 was statistically significant (17.3% vs. 20.4%, p = 0.0311). There were no significant differences among the dose-volume parameters of the contralateral breast. Conclusion: The target volume can be properly irradiated by both techniques with high conformity and similar dose to the OARs. MIBT provides more advantageous plans than CK, except for dose conformity and the dosimetry of the heart and contralateral breast. More studies are needed to analyze whether these dosimetrical findings have clinical significance.

Comparative dosimetrical analysis of intensity-modulated arc therapy, CyberKnife therapy and image-guided interstitial HDR and LDR brachytherapy of low risk prostate cancer.

BACKGROUND: The objective of the study was to dosimetrically compare the intensity-modulated-arc-therapy (IMAT), Cyber-Knife therapy (CK), single fraction interstitial high-dose-rate (HDR) and low-dose-rate (LDR) brachytherapy (BT) in low-risk prostate cancer. MATERIALS AND METHODS: Treatment plans of ten patients treated with CK were selected and additional plans using IMAT, HDR and LDR BT were created on the same CT images. The prescribed dose was 2.5/70 Gy in IMAT, 8/40 Gy in CK, 21 Gy in HDR and 145 Gy in LDR BT to the prostate gland. EQD2 dose-volume parameters were calculated for each technique and compared. RESULTS: EQD2 total dose of the prostate was significantly lower with IMAT and CK than with HDR and LDR BT, D90 was 79.5 Gy, 116.4 Gy, 169.2 Gy and 157.9 Gy (p < 0.001). However, teletherapy plans were more conformal than BT, COIN was 0.84, 0.82, 0.76 and 0.76 (p < 0.001), respectively. The D2 to the rectum and bladder were lower with HDR BT than with IMAT, CK and LDR BT, it was 66.7 Gy, 68.1 Gy, 36.0 Gy and 68.0 Gy (p = 0.0427), and 68.4 Gy, 78.9 Gy, 51.4 Gy and 70.3 Gy (p = 0.0091) in IMAT, CK, HDR and LDR BT plans, while D0.1 to the urethra was lower with both IMAT and CK than with BTs: 79.9 Gy, 88.0 Gy, 132.7 Gy and 170.6 Gy (p < 0.001). D2 to the hips was higher with IMAT and CK, than with BTs: 13.4 Gy, 20.7 Gy, 0.4 Gy and 1.5 Gy (p < 0.001), while D2 to the sigmoid, bowel bag, testicles and penile bulb was higher with CK than with the other techniques. CONCLUSIONS: HDR monotherapy yields the most advantageous dosimetrical plans, except for the dose to the urethra, where IMAT seems to be the optimal modality in the radiotherapy of low-risk prostate cancer.

[Second breast conserving surgery and interstitial radiotherapy for the treatment of breast tumor local recurrences. Five-year results]. / Második emlomegtartó mutét és szövetközi sugárkezelés az emlodaganat lokális kiújulásának kezelésére. Ötéves eredmények.

INTRODUCTION AND AIM: To report the clinical outcomes of second breast-conserving therapy with perioperative interstitial radiotherapy for the treatment of ipsilateral breast tumor recurrences. METHOD: Between 1999 and 2015, 33 patients, presenting with an ipsilateral breast tumor recurrence after previous breast conserving therapy, were salvaged by re-excision and perioperative high-dose-rate interstitial brachytherapy. A median of 8 (range: 4-24) catheters were implanted into the tumor bed intraoperatively. A total dose of 22 Gy in 5 fractions of 4.4 Gy was delivered to the tumor bed with a margin of 1-2 cm, on 3 consecutive days. The adjuvant systemic treatments consisted of hormonal therapy for 24 patients (73%) and chemotherapy for 6 patients (18%). The survival results were estimated by the Kaplan-Meier method. Late side effects and cosmetic results were also registered. RESULTS: The median follow-up time following the second breast conserving therapy was 61 months (range: 26-189 months). During the follow-up, 4 patients (12.1%) developed second local recurrence. The five-year actuarial rates of the second local, regional and distant recurrence were 6.3%, 6.1%, and 14.9%, respectively. The five-year probabilities of disease-free, cancer-specific and overall survival were 76.2%, 92.4%, and 89.2%, respectively. Four (12%), 19 (58%), 4 (12%) and 6 (18%) patients had excellent, good, fair and poor cosmetic results, respectively. Grade 2 and 3 fibrosis developed in 9 (27%) and 1 (3%) patients. Asymptomatic fat necrosis was detected in 7 (21%) women. CONCLUSION: Second breast conserving therapy with perioperative high-dose-rate interstitial brachytherapy is a safe and feasible option for the management of ipsilateral breast tumor recurrences. Interstitial brachytherapy may decrease the risk of second local relapse with acceptable cosmetic results and low rate of late side effects. Hence, in selected cases it can provide a feasible alternative to salvage mastectomy. Orv Hetil. 2018; 159(11): 430-438.

[Stereotactic body radiotherapy of liver metastasis: early experience]. / Májáttétes betegek sztereotaxiás ablatív sugárkezelésével (SABRT) elért elsõ eredményeink.

Recently the prevalence of oligometastatic patients is increasing. A common site of distant spread is the liver. The standard of care is curative surgical resection, however, the resecability rate is only 10-20%. Alternatively, radiofrequency ablation (RFA) or transarterial chemoembolization (TACE) may be used. Stereotactic ablative body radiotherapy (SABRT) makes it possible to deliver curative radiation dose without radiation injury to the healthy liver tissue. We delivered SABRT to three patients with inoperable hepatic metastases. The primary tumors were rectal (2) and lung (1). The dose was 3x20 Gy every other day. We observed one grade 1 side effect. All the metastases showed complete remission and no local recurrence or late side effect occurred during the one year of follow-up. One patient is tumor-free, one has stable disease, in one patient two new hepatic metastases appeared and receives chemo-biological therapy. SABRT of liver metastases is safe and highly effective. It can be expected that in the near future it will become one of the standard treatments of hepatic tumors.

Implementation of image-guided intensity-modulated accelerated partial breast irradiation : Three-year results of a phase II clinical study.

PURPOSE: To report 3­year results of accelerated partial breast irradiation (APBI) using image-guided intensity-modulated radiotherapy (IG-IMRT) following breast conserving surgery (BCS) for low-risk early invasive breast cancer. PATIENTS AND METHODS: Between July 2011 and March 2014, 60 patients with low-risk early invasive breast cancer underwent BCS and were enrolled in this phase II prospective study. The total dose was 36.9 Gy (9 fractions of 4.1 Gy, two fractions/day). Patient setup errors were detected in LAT, LONG and VERT directions. Local tumour control, survival results, early and late side effects and cosmetic outcome were assessed. RESULTS: At a median follow-up of 39 months, all patients were alive and neither locoregional nor distant failure occurred. One contralateral breast cancer and two new primary malignancies outside the breast were observed. No grade (G) 3-4 acute toxicity was detected. G1 and G2 erythema occurred in 21 (35%) and 2 (3.3%) patients, respectively; while G1 oedema was observed in 23 (38.8%) cases. G1 and G2 pain was reported by 6 (10%) and 2 (3.3%) patients, respectively. Among the late radiation side effects, G1 pigmentation or telangiectasia, G1 fibrosis and G1 asymptomatic fat necrosis occurred in 10 (16.7%), 7 (11.7%) and 3 (5%) patients, respectively. No ≥ G2 late toxicity was detected. Cosmetic outcome was excellent in 43 (71.7%) and good in 17 (28.3%) patients. CONCLUSION: IG-IMRT is a reproducible and feasible technique for delivery of external beam APBI following BCS for treatment of low-risk, early-stage invasive breast carcinoma. In order to avoid toxicity, image guidance performed before each radiation fraction is necessary to minimize the PTV. Three-year results are promising, early and late radiation side-effects are minimal, and cosmetic results are excellent to good.

Atypical teratoid/rhabdoid tumor arising in a malignant glioma.

Atypical teratoid/rhabdoid tumor (AT/RT), a highly malignant brain tumor in young children, usually arises de novo and has only rarely been described as a secondary malignancy. Here, we present a case of a child with glioblastoma, who was treated postoperatively by a combination of temozolomide, irradiation, and bevacizumab. AT/RT was diagnosed as a secondary tumor, 2.5 years following primary diagnosis. The child died 13 months after the diagnosis of AT/RT. This case demonstrates that malignant gliomas may give rise to AT/RT. It also emphasizes the diagnostic value of a repeated tumor biopsy in the recurrence setting.

[Image-guided radiotherapy for muscle invasive bladder cancer with intravesical lipiodol injection. A new option for bladder sparing treatment]. / Izominvazív hólyagrák képvezérelt sugárkezelése intravesicalisan befecskendezett lipiodolos jelöléssel. A hólyagmegtartó kezelés új lehetosége.

INTRODUCTION AND AIM: To implement lipiodol as a fiducial marker of the tumor bed for image-guided radiotherapy with simultaneous integrated boost technique as part of radiochemotherapy for muscle invasive bladder tumors. METHOD: Since April 2016, radiochemotherapy was performed in 3 male patients with muscle invasive, transitional cell bladder carcinoma. Prior to radiochemotherapy, tumor bed resection was performed for each patient, at the same time 10 ml of lipiodol solution was injected submucosally into the resection site, thus marking the tumor bed for escalated dose irradiation. During radiochemotherapy 51 Gy (1.7 Gy/die) to the pelvis, 57 Gy (1.9 Gy/die) to the whole bladder, and 63 Gy (2.1 Gy/die) to the lipiodol-labeled tumor bed was delivered with simultaneous integrated boost technique. The accuracy of the irradiation was controlled by daily kilovoltage CT. Early radiogenic urogenital and gastrointestinal side effects were recorded according to Radiation Therapy Oncology Group side-effects grading recommendation. RESULTS: Substantial perioperative side effect or toxicity were not observed during and after the injection of lipiodol. The prescribed dose was successfully delivered in all patients. Radiotherapy duration was 6 weeks. The lipiodol-labeled tumor bed was clearly visible on daily kilovoltage cone beam CT. In one patient grade II cystitis and proctitis was observed, another patient experienced only grade I cystitis. These complaints improved with symptomatic medication. In the third patient no significant side effect occurred. CONCLUSIONS: The injection of lipiodol into the bladder wall is a safe technique, without any perioperative toxicity or complication. The tumor bed demarcated by lipiodol was visible both on treatment planning and kilovoltage CTs. The total treatment time was shortened by 4 days. The treatment was well tolerated, early side effects were moderate, or slight. Orv Hetil. 2017; 158(51): 2041-2047.

[Stereotactic ablative body radiotherapy (SABRT) for locally advanced pancreatic cancer. Case report and review of literature]. / Lokálisan kiterjedt hasnyálmirigy-daganatos beteg sztereotaxiás ablatív sugárkezelése (SABRT): esetismertetés és irodalmi áttekintés.

Pancreatic cancer has one of the worst outcomes among malignant tumors. At the time of diagnosis only 20% of the cases are resectable and 30-50% are locally advanced, when curative intervention cannot be performed. After resection local relapse occurs in 20-60%, and in 30% it is the reason of death. This latter highlights the importance of local control. However, there have been no convincing results with conformal radiation therapy and radiochemotherapy yet. Adjuvant radiochemotherapy has been settled into the routine in the US, but not in Europe and Asia and only sporadic data are available about neoadjuvant radiotherapy. Based on the result of recent studies, conformal radiation therapy does not seem to become part of the standard treatment of locally advanced disease. Radiation resistance, long treatment time and incompatibility with the most advanced chemotherapy regimens may make conformal radiotherapy ineffective. Stereotactic ablative body radiotherapy (SABRT) when a limited target volume is irradiated in few fractions, with high precision and high biological effective dose, is ablative for the tumor and could be a possible solution for this issue. In our report, we describe to our knowledge the first SABRT for locally advanced pancreatic cancer in Hungary and give a short literature review.

[Dosimetric comparison of different techniques for external beam accelerated partial breast irradiation]. / Modern besugárzási technikák dozimetriai összehasonlítása gyorsított részleges külsõ emlõbesugárzásnál.

The aim of this article is to evaluate and compare four different radiotherapy techniques of accelerated partial breast irradiation (APBI) considering planning quality, dosimetric and practical aspects. The investigated techniques are three dimensional conformal radiotherapy (3D-CRT), "step and shoot" (SS) and "sliding window" (SW) intensity-modulated radiotherapy, intensity-modulated arc therapy (RA). CT scans of 10 patients previously treated with APBI were selected for the study. Surgical clips were placed on the borders of the tumour bed during breast conserving surgery. Target volume (PTV) was defined as enlarged CTV, which was created from the tumour bed through volume expansion using individual margins. Planning objectives were set up according to the international recommendations. Non-coplanar fields were used only for the 3D-CRT plans. For each plan homogeneity, conformity and plan quality indices were calculated from volumetric and dosimetric parameters of target volumes and organs at risk. The total monitor units and feasibility were also investigated. There was no significant difference in the coverage of the target volume by the prescribed dose between the techniques. SW plans were significantly more homogeneous (HI=0.033) than the 3D-CRT (HI=0.057) and the RA (HI=0.073) plans. The homogeneity of the SS technique (HI=0.053) did not differ significantly compared to others. The conformity of the 3D-CRT technique was significantly worse (CN=0.62) than that of SS (CN=0.85), SW (CN=0.85) and RA (CN=0.86) plans. There was a significant difference between RA (29.4%) and 3D-CRT (44.1%) and SW (35.6%) plans in the V50% of the ipsilateral breast. Mean V10% of the ipsilateral lung in 3D-CRT (10.1%) plans was significantly lower than in SS (34.3%), SW (34.3%) and RA (35.3%) plans. 3D-CRT technique provided the best heart protection. The shortest treatment times were achieved with RA technique. Good target volume coverage and tolerable dose to the organs at risk are achievable with all four techniques. Taking into account all the aspects, we recommend the sliding window IMRT technique for accelerated partial breast irradiation.

[Investigating the clinical applicability of EBT2 self-developing films]. / Az EBT2 önhívó filmek sugárterápiás klinikai alkalmazhatóságának vizsgálata.

The purpose of the study was to investigate the physical properties of the EBT2 radiochromic films and define the conditions of its clinical applicability. We irradiated the films with different treatment techniques 3D conformal (3DCRT), intensity-modulated (IMRT) and stereotactic body radiotherapy with arc therapy (SBRT), and then compared the data with the dose distribution exported from the treatment planning system (Eclipse). Two film analysis softwares were investigated for the comparison: PTW Mephysto and FilmQA Pro. The comparisons of dose distributions were performed with gamma analysis, and the gamma criterion was 3%, 3mm, and 2%, 2mm. The gamma analysis results by the two programs were the following, (PTW/FilmQA Pro) with 3%, 3mm gamma criterion: 3DCRT (95,5/100%), IMRT (97/99,9%), SBRT (99,7/100%). In case of 2%, 2mm the results were: 3DCRT (87,1/98,9%), IMRT (92/98,5%), SBRT (96,7/97,9%). Based on the results it can be stated that during proper use, the features of the scanner do not affect the results. Both evaluation softwares are suitable for calibrating and evaluating films, moreover, performing the gamma analysis. The EBT2 film is suitable for the two-dimensional controlling of radiation therapy plans.

[Accelerated partial breast irradiation with image-guided intensity-modulated radiotherapy following breast-conserving surgery - preliminary results of a phase II clinical study]. / Gyorsított, részleges külsõ emlõbesugárzás képvezérelt, intenzitásmodulált radioterápiával emlõmegtartó mûtét után - Fázis II klinikai vizsgálat elõzetes eredményei.

The purpose of the study was to implement accelerated partial breast irradiation (APBI) by means of image-guided intensity-modulated radiotherapy (IG-IMRT) following breast-conserving surgery (BCS) for low-risk early invasive breast cancer. Between July 2011 and March 2014, 60 patients with low-risk early invasive (St I-II) breast cancer who underwent BCS were enrolled in our phase II prospective study. Postoperative APBI was given by means of step and shoot IG-IMRT using 4 to 5 fields to a total dose of 36.9 Gy (9×4.1 Gy) using a twice-a-day fractionation. Before each fraction, series of CT images were taken from the region of the target volume using a kV CT on-rail mounted in the treatment room. An image fusion software was used for automatic image registration of the planning and verification CT images. Patient set-up errors were detected in three directions (LAT, LONG, VERT), and inaccuracies were adjusted by automatic movements of the treatment table. Breast cancer related events, acute and late toxicities, and cosmetic results were registered and analysed. At a median follow-up of 24 months (range 12-44) neither locoregional nor distant failure was observed. Grade 1 (G1), G2 erythema, G1 oedema, and G1 and G2 pain occurred in 21 (35%), 2 (3.3%), 23 (38.3%), 6 (10%) and 2 (3.3%) patients, respectively. No G3-4 acute side effects were detected. Among late radiation side effects G1 pigmentation, G1 fibrosis, and G1 fat necrosis occurred in 5 (8.3%), 7 (11.7%), and 2 (3.3%) patients, respectively. No ≥G2 late toxicity was detected. Excellent and good cosmetic outcome was detected in 45 (75%) and 15 (25%) patients. IG-IMRT is a reproducible and feasible technique for the delivery of APBI following conservative surgery for the treatment of low-risk, early-stage invasive breast carcinoma. Preliminary results are promising, early radiation side effects are minimal, and cosmetic results are excellent.

Accelerated partial breast irradiation with external beam three-dimensional conformal radiotherapy. Five-year results of a prospective phase II clinical study.

PURPOSE: The aim of this study was to report the 5-year results of accelerated partial breast irradiation (APBI) using external beam three-dimensional conformal radiotherapy (3D-CRT). PATIENTS AND METHODS: Between 2006 and 2011, 44 patients with low-risk, stage I-II breast cancer underwent breast-conserving surgery. Postoperative APBI was given by means of 3D-CRT using three to five non-coplanar fields. The total dose of APBI was 36.9 Gy (nine fractions of 4.1 Gy b.i.d.). The mean follow-up time was 58.2 months for surviving patients. Survival results, side effects, and cosmetic results were assessed. RESULTS: One (2.3%) local recurrence was observed, for a 5-year actuarial rate of 3.7%. Neither regional nor distant failure was observed. Two patients died of internal disease. The 5-year disease-free, cancer-specific, and overall survival rates were 96.3, 100, and 95.1%, respectively. Acute side effects included grade 1 (G1) erythema in 75%, G1 parenchymal induration in 46%, and G1 pain in 46% of patients. No G2 or higher acute side effect occurred. Late side effects included G1, G2, and G3 fibrosis in 44, 7, and 2% of patients, respectively, G1 skin pigmentation in 12%, and G1 pain in 2%. Asymptomatic fat necrosis occurred in 14%. Cosmetic results were rated excellent or good in 86% of cases by the patients themselves and 84% by the physicians. CONCLUSIONS: The 5-year local tumor control, toxicity profile, and cosmetic results of APBI delivered with external beam 3D-CRT are encouraging and comparable to other APBI series.

On dosimetric characteristics of detectors for relative dosimetry in small fields: a multicenter experimental study.

Objective. In this multicentric collaborative study, we aimed to verify whether the selected radiation detectors satisfy the requirements of TRS-483 Code of Practice for relative small field dosimetry in megavoltage photon beams used in radiotherapy, by investigating four dosimetric characteristics. Furthermore, we intended to analyze and complement the recommendations given in TRS-483.Approach. Short-term stability, dose linearity, dose-rate dependence, and leakage were determined for 17 models of detectors considered suitable for small field dosimetry. Altogether, 47 detectors were used in this study across ten institutions. Photon beams with 6 and 10 MV, with and without flattening filters, generated by Elekta Versa HDTMor Varian TrueBeamTMlinear accelerators, were used.Main results. The tolerance level of 0.1% for stability was fulfilled by 70% of the data points. For the determination of dose linearity, two methods were considered. Results from the use of a stricter method show that the guideline of 0.1% for dose linearity is not attainable for most of the detectors used in the study. Following the second approach (squared Pearson's correlation coefficientr2), it was found that 100% of the data fulfill the criteriar2> 0.999 (0.1% guideline for tolerance). Less than 50% of all data points satisfied the published tolerance of 0.1% for dose-rate dependence. Almost all data points (98.2%) satisfied the 0.1% criterion for leakage.Significance. For short-term stability (repeatability), it was found that the 0.1% guideline could not be met. Therefore, a less rigorous criterion of 0.25% is proposed. For dose linearity, our recommendation is to adopt a simple and clear methodology and to define an achievable tolerance based on the experimental data. For dose-rate dependence, a realistic criterion of 1% is proposed instead of the present 0.1%. Agreement was found with published guidelines for background signal (leakage).

Acute side effects after definitive stereotactic body radiation therapy (SBRT) for patients with clinically localized or locally advanced prostate cancer: a single institution prospective study.

BACKGROUND: The aim of the study was to evaluate acute side effects after extremely hypofractionated intensity-modulated radiotherapy (IMRT) with stereotactic body radiation therapy (SBRT) for definitive treatment of prostate cancer patients. PATIENTS AND METHODS: Between February 2018 and August 2019, 205 low-, intermediate- and high-risk prostate cancer patients were treated with SBRT using "CyberKnife M6" linear accelerator. In low-risk patients 7.5-8 Gy was delivered to the prostate gland by each fraction. For intermediate- and high-risk disease a dose of 7.5-8 Gy was delivered to the prostate and 6-6.5 Gy to the seminal vesicles by each fraction with a simultaneous integrated boost (SIB) technique. A total of 5 fractions (total dose 37.5-40 Gy) were given on every second working day. Acute radiotherapy-related genitourinary (GU) and gastrointestinal (GI) side effects were assessed using Radiation Therapy Oncology Group (RTOG) scoring system. RESULTS: Of the 205 patients (28 low-, 115 intermediate-, 62 high-risk) treated with SBRT, 203 (99%) completed the radiotherapy as planned. The duration of radiation therapy was 1 week and 3 days. The frequencies of acute radiotherapy-related side effects were as follows: GU grade 0 - 17.1%, grade I - 30.7%, grade II - 50.7%, grade III - 1.5%; and GI grade 0 - 62.4%, grade I-31.7%, grade II-5.9%, grade III-0%. None of the patients developed grade ≥ 4 acute toxicity. CONCLUSIONS: SBRT with a total dose of 37.5-40 Gy in 5 fractions appears to be a safe and well tolerated treatment option in patients with prostate cancer, associated with slight or moderate early side effects. Longer follow-up is needed to evaluate long-term toxicity and biochemical control.

Is stereotactic CyberKnife radiotherapy or multicatheter HDR brachytherapy the better option dosimetrically for accelerated partial breast irradiation?

OBJECTIVE: To compare dosimetrically the stereotactic CyberKnife (CK) therapy and multicatheter high-dose-rate (HDR) brachytherapy (BT) for accelerated partial breast irradiation (APBI). METHODS: Treatment plans of 25 patients treated with CK were selected, and additional plans using multicatheter HDR BT were created on the same CT images. The prescribed dose was 6.25/25 Gy in both plans to the target volume (PTV). The dose-volume parameters were calculated for both techniques and compared. RESULTS: The D90 total dose of the PTV was significantly lower with CK than with HDR BT, D90 was 25.7 Gy, and 27.0 Gy (p < 0.001). However, CK plans were more conformal than BT, COIN was 0.87, and 0.81 (p = 0.0030). The V50 of the non-target breast was higher with CK than with BT: 10.5% and 3.3% (p = 0.0010), while there was no difference in the dose of the contralateral breast and contralateral lung. Dose to skin, ipsilateral lung, and ribs were higher with CK than with BT: D1 was 20.6 Gy vs. 11.5 Gy (p = 0.0018) to skin, 11.4 Gy vs. 9.6 Gy (p = 0.0272) to ipsilateral lung and 18.5 Gy vs. 12.3 Gy (p = 0.0013) to ribs, while D0.1 to heart was lower, 3.0 Gy vs. 3.2 Gy (p = 0.0476), respectively. CONCLUSIONS: Multicatheter HDR BT yields more advantageous plans than stereotactic CyberKnife treatment in accelerated partial breast irradiation, except in terms of dose conformality and the dose to the heart. There was no difference in the dose of the contralateral breast and lung.

Multicatheter interstitial brachytherapy versus stereotactic radiotherapy with CyberKnife for accelerated partial breast irradiation: a comparative treatment planning study with respect to dosimetry of organs at risk.

BACKGROUND: The aim of the study was to dosimetrically compare multicatheter interstitial brachytherapy (MIBT) and stereotactic radiotherapy with CyberKnife (CK) for accelerated partial breast irradiation (APBI) especially concerning the dose of organs at risk (OAR-s). PATIENTS AND METHODS: Treatment plans of thirty-two MIBT and CK patients were compared. The OAR-s included ipsilateral non-target and contralateral breast, ipsilateral and contralateral lung, skin, ribs, and heart for left-sided cases. The fractionation was identical (4 x 6.25 Gy) in both treatment groups. The relative volumes (e.g. V100, V90) receiving a given relative dose (100%, 90%), and the relative doses (e.g. D0.1cm3, D1cm3) delivered to the most exposed small volumes (0.1 cm3, 1 cm3) were calculated from dose-volume histograms. All dose values were related to the prescribed dose (25 Gy). RESULTS: Regarding non-target breast CK performed slightly better than MIBT (V100: 0.7% vs. 1.6%, V50: 10.5% vs. 12.9%). The mean dose of the ipsilateral lung was the same for both techniques (4.9%), but doses irradiated to volume of 1 cm3 were lower with MIBT (36.1% vs. 45.4%). Protection of skin and rib was better with MIBT. There were no significant differences between the dose-volume parameters of the heart, but with MIBT, slightly larger volumes were irradiated by 5% dose (V5: 29.9% vs. 21.2%). Contralateral breast and lung received a somewhat higher dose with MIBT (D1cm3: 2.6% vs. 1.8% and 3.6% vs. 2.5%). CONCLUSIONS: The target volume can be properly irradiated by both techniques with similar dose distributions and high dose conformity. Regarding the dose to the non-target breast, heart, and contralateral organs the CK was superior, but the nearby organs (skin, ribs, ipsilateral lung) received less dose with MIBT. The observed dosimetric differences were small but significant in a few parameters at the examined patient number. More studies are needed to explore whether these dosimetric findings have clinical significance.

Relationship between biodosimetric parameters and treatment volumes in three types of prostate radiotherapy.

Brachytherapy (BT) and external beam radiotherapy (EBRT) apply different dose rates, overall treatment times, energies and fractionation. However, the overall impact of these variables on the biological dose of blood is neglected. As the size of the irradiated volume influences the biological effect as well, we studied chromosome aberrations (CAs) as biodosimetric parameters, and explored the relationship of isodose surface volumes (ISVs: V1%, V1Gy, V10%, V10Gy, V100%, V150%) and CAs of both irradiation modalities. We performed extended dicentrics assay of lymphocytes from 102 prostate radiotherapy patients three-monthly for a year. Aberration frequency was the highest after EBRT treatment. It increased after the therapy and did not decrease significantly during the first follow-up year. We showed that various types of CAs 9 months after LDR BT, 3 months after HDR BT and in a long time-range (even up to 1 year) after EBRT positively correlated with ISVs. Regression analysis confirmed these relationships in the case of HDR BT and EBRT. The observed differences in the time points and aberration types are discussed. The ISVs irradiated by EBRT showed stronger correlation and regression relationships with CAs than the ISVs of brachytherapy.

Accelerated partial breast irradiation with 3-dimensional conformal and image-guided intensity-modulated radiotherapy following breast conserving surgery - 7-Year results of a phase II trial.

PURPOSE: To present the 7-year results of accelerated partial breast irradiation (APBI) using three-dimensional conformal (3D-CRT) and image-guided intensity-modulated radiotherapy (IG-IMRT) following breast-conserving surgery (BCS). PATIENTS AND METHODS: Between 2006 and 2014, 104 patients were treated with APBI given by means of 3D-CRT using 3-5 non-coplanar, isocentric wedged fields, or IG-IMRT using kV-CBCT. The total dose of APBI was 36.9 Gy (9 × 4.1 Gy) using twice-a-day fractionation. Survival results, side effects and cosmetic results were assessed. RESULTS: At a median follow-up of 90 months three (2.9%) local recurrences, one (0.9%) regional recurrence and two (1.9%) distant metastases were observed. The 7-year local (LRFS), recurrence free survival was 98.9%. The 7-year disease-free (DFS), metastases free (MFS) and overall survival (OS) was 94.8%, 97.9% and 94.8%, respectively. Late side effects included G1 skin toxicity in 15 (14.4%), G1, G2, and G3 fibrosis in 26 (25%), 3 (2.9%) and 1 (0.9%) patients respectively. Asymptomatic (G1) fat necrosis occurred in 10 (9.6%) patients. No ≥ G2 or higher late side effects occurred with IMRT. The rate of excellent/good and fair/poor cosmetic results was 93.2% and 6.8%, respectively. CONCLUSION: 7-year results of APBI with 3D-CRT and IG-IMRT are encouraging. Toxicity profile and local tumor control are comparable to other series using multicatheter interstitial brachytherapy. Therefore, these external beam APBI techniques are valid alternatives to whole breast irradiation and brachytherapy based APBI.

Acute and Late Toxicity after Moderate Hypofractionation with Simultaneous Integrated Boost (SIB) Radiation Therapy for Prostate Cancer. A Single Institution, Prospective Study.

ASBTRACT: To evaluate the acute and late toxicity using moderately hypofractionated, intensity-modulated radiotherapy (IMRT) with a simultaneous integrated boost (SIB) to prostate for patients with intermediate and high risk prostate cancer. From 2015 to 2017, 162 patients were treated with IMRT with SIB to the prostate. IMRT plans were designed to deliver 50.4Gy in 28 fractions (1.8 Gy/fraction) to the pelvic lymph nodes (whole pelvis radiotherapy, WPRT) while simultaneously delivering 57.4 Gy in 28 fractions (2.05 Gy/fraction) to the seminal vesicles and 70 Gy in 28 fractions (2.5 Gy/fraction) to the prostate for high risk patients. For intermediate risk patients the same technique was applied, without WPRT. Acute and cumulative late genitourinary (GU) and gastrointestinal (GI) toxicities were scored according to the Radiation Therapy Oncology Group (RTOG) scoring system. Of the 162 patients enrolled, 156 (96%) completed the treatment as planned. The median follow-up time was 30 months. Seventy-eight patients (48.2%) were treated with WPRT. The rate of acute grade ≥ 2 GI and GU toxicities in all patients were 22% and 58%, respectively. The rate of cumulative late grade ≥ 2 GI and GU toxicities were 11% and 17%, respectively. Acute grade 3 GI and GU toxicities occurred in 1% and 1%. Late grade 3 GI and GU side effects occurred in 5% and 4%, respectively. None of the patients developed grade ≥ 4 toxicity. IMRT with SIB technique using moderate hypofractionation to the prostate is feasible treatment option for intermediate and high risk patients, associated with low rate of severe GU and GI toxicities.

Implementation of Stereotactic Accelerated Partial Breast Irradiation Using Cyber-Knife - Technical Considerations and Early Experiences of a Phase II Clinical Study.

To report the implementation, dosimetric results of and early experiences with stereotactic accelerated partial breast irradiation (SAPBI) following breast conserving surgery (BCS) for postmenopausal low-risk St I-II invasive breast cancer (IBC) patients. Between November 2018 and August 2019, 27 patients were registered in our phase II prospective study. SAPBI was performed with Cyber-Knife (CK) M6 machine, in 4 daily fractions of 6.25 Gy to a total dose of 25 Gy. Respiratory movements were followed with implanted gold markers and Synchrony system. Corrections for patient displacement and respiratory movement during treatment were performed with the robotic arm. Early side effects, cosmetic results, and dosimetric parameters were assessed. The average volume of the surgical cavity, clinical target volume (CTV), and planning target volume (PTV_EVAL) were 8.1 cm3 (range: 1.75-27.3 cm3), 55.3 cm3 (range: 26.2-103.5 cm3), and 75.7 cm3 (range: 40-135.4 cm3), respectively. The mean value of the PTV_eval/whole breast volume ratio was 0.09 (range: 0.04-0.19). No grade 2 or worst acute side-effect was detected. Grade 1 (G1) erythema occurred in 6 (22.2%) patients, while G1 oedema was reported by 3 (11.1%) cases. G1 pain was observed in 1 (3.4%) patient. Cosmetic result were excellent in 17 (62.9%) and good in 10 (37.1%) patients. SAPBI with CK is a suitable and practicable technique for the delivery of APBI after BCS for low-risk, St. I-II. IBC. Our early findings are encouraging, CK-SAPBI performed with four daily fractions is convenient and perfectly tolerated by the patients.