Five year outcomes of hypofractionated simultaneous integrated boost irradiation in breast conserving therapy; patterns of recurrence

Simultaneous integrated boost intensity-modulated radiotherapy post breast-conserving surgery: clinical efficacy, adverse effects, and cosmetic outcomes in breast cancer patients

BACKGROUND

Simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) is an innovative technique delivering a higher dose to the tumor bed while irradiating the entire breast. This study aims to assess the clinical outcomes, adverse effects, and cosmetic results of SIB-IMRT following breast-conserving surgery in breast cancer patients.

METHODS

We conducted a retrospective analysis of 308 patients with stage 0-III breast cancer who underwent breast-conserving surgery and SIB-IMRT from January 2016 to December 2020. The prescribed doses included 1.85 Gy/27 fractions to the whole breast and 2.22 Gy/27 fractions or 2.20 Gy/27 fractions to the tumor bed. Primary endpoints included overall survival (OS), local-regional control (LRC), distant metastasis-free survival (DMFS), acute and late toxicities, and cosmetic outcomes.

RESULTS

The median follow-up time was 36 months. The 3-year OS, LRC, and DMFS rates were 100%, 99.6%, and 99.2%, respectively. Five patients (1.8%) experienced local recurrence or distant metastasis, and one patient succumbed to distant metastasis. The most common acute toxicity was grade 1-2 skin reactions (91.6%). The most common late toxicity was grade 0-1 skin and subcutaneous tissue reactions (96.7%). Five patients (1.8%) developed grade 1-2 upper limb lymphedema, and three patients (1.1%) had grade 1 radiation pneumonitis. Among the 262 patients evaluated for cosmetic outcomes at least 2 years post-radiotherapy, 96.9% achieved excellent or good results, while 3.1% had fair or poor outcomes.

CONCLUSIONS

SIB-IMRT after breast-conserving surgery in breast cancer patients demonstrated excellent clinical efficacy, mild acute and late toxicities, and satisfactory cosmetic outcomes in our study. SIB-IMRT appears to be a feasible and effective option for breast cancer patients suitable for breast-conserving surgery.

A Beam Angle Selection Method to Improve Plan Robustness Against Position Error in Intensity-Modulated Radiotherapy for Left-Sided Breast Cancer

PURPOSE

We report a dosimetric study in whole breast irradiation (WBI) of plan robustness evaluation against position error with two radiation techniques: tangential intensity-modulated radiotherapy (T-IMRT) and multi-angle IMRT (M-IMRT).

METHODS

Ten left-sided patients underwent WBI were selected. The dosimetric characteristics, biological evaluation and plan robustness were evaluated. The plan robustness quantification was performed by calculating the dose differences (Δ) of the original plan and perturbed plans, which were recalculated by introducing a 3-, 5-, and 10-mm shift in 18 directions.

RESULTS

M-IMRT showed better sparing of high-dose volume of organs at risk (OARs), but performed a larger low-dose irradiation volume of normal tissue. The greater shift worsened plan robustness. For a 10-mm perturbation, greater dose differences were observed in T-IMRT plans in nearly all directions, with higher ΔD98%, ΔD95%, and ΔDmean of CTV Boost and CTV. A 10-mm shift in inferior (I) direction induced CTV Boost in T-IMRT plans a 1.1 (ΔD98%), 1.1 (ΔD95%), and 1.7 (ΔDmean) times dose differences greater than dose differences in M-IMRT plans. For CTV Boost, shifts in the right (R) and I directions generated greater dose differences in T-IMRT plans, while shifts in left (L) and superior (S) directions generated larger dose differences in M-IMRT plans. For CTV, T-IMRT plans showed higher sensitivity to a shift in the R direction. M-IMRT plans showed higher sensitivity to shifts in L, S, and I directions. For OARs, negligible dose differences were found in V20 of the lungs and heart. Greater ΔDmax of the left anterior descending artery (LAD) was seen in M-IMRT plans.

CONCLUSION

We proposed a plan robustness evaluation method to determine the beam angle against position uncertainty accompanied by optimal dose distribution and OAR sparing.

Accelerated hypofractionated breast radiotherapy with simultaneous integrated boost: a feasibility study

Purpose

To assess the feasibility of accelerated hypofractionated radiotherapy with simultaneous integrated boost (SIB) in patients with breast cancer.

Materials and Methods

A total of 27 patients after breast-conserving surgery were included in this study. Patients were planned on a four-dimensional computerized tomogram, and contouring was done using RTOG guidelines. The dose was 34 Gy/10#/2 week to the breast and 40 Gy/10#/2 week to the tumor bed as SIB with volumetric modulated arc technique. The primary endpoint was grade 2 acute skin toxicity. Doses to the organs-at-risk were calculated. Toxicities and cosmesis were assessed using RTOG/LENT/SOMA and HARVARD/NSABP/RTOG grading scales, respectively. Disease-free survival (DFS) and overall survival (OS) were calculated with Kaplan-Meier curves.

Results

The mean age of the patients was 42 years. Left and right breast cancers were seen in 17 (63%) and 10 (37%) patients, respectively. The mean values of ipsilateral lung V₁₆ and contralateral lung V₅ were 16.01% and 3.74%, respectively. The mean heart doses from the left and right breast were 7.25 Gy and 4.37 Gy, respectively. The mean doses to the contralateral breast, oesophagus, and D_max to brachial plexus were 2.64 Gy, 3.69 Gy, and 26.95 Gy, respectively. The mean value of thyroid V₂₅ was 19.69%. Grade 1 and 2 acute skin toxicities were observed in 9 (33%) and 5 (18.5%) patients, respectively. Grade 2 hyperpigmentation, edema, and induration were observed in 1 (3.7%), 2 (7.4%), and 4 (14.8%) patients, respectively. Mild breast pain and arm/shoulder discomfort were reported by 1 (3.4%) patient. The median follow-up was 51 months (range, 12 to 61 months). At four years, breast induration, edema, and fibrosis were observed in 1 (3.7%) patient. Cosmesis was excellent and good in 21 (78%) and 6 (22%) patients, respectively. Local recurrence and distant metastases occurred in 1 (3.7%) and 2 (7.4%) patients, respectively. DFS and OS at four years were 88% and 92%, respectively.

Conclusion

With this radiotherapy schedule, acute and late toxicity rates were acceptable with no adverse cosmesis. Local control, DFS, and OS were good.

Evaluation of Plan Robustness Using Hybrid Intensity-Modulated Radiotherapy (IMRT) and Volumetric Arc Modulation Radiotherapy (VMAT) for Left-Sided Breast Cancer

Purpose: We aim to evaluate the robustness of multi-field IMRT and VMAT plans to target motion for left-sided BC radiotherapy. Methods: The 7-field hybrid IMRT (7F-H-IMRT) and 2-arc VMAT (2A-VMAT) plans were generated for ten left-sided BC patients. Shifts of 3 mm, 5 mm, and 10 mm in six directions were introduced and the perturbed dose distributions were recalculated. The dose differences (∆D) of the original plan and perturbed plan corresponded to the plan robustness for the structure. Results: Higher ∆D_98%, ∆D_95%, and ∆D_mean of CTV were observed in 2A-VMAT plans, which induced higher tumor control probability reductions. A higher ∆Dmean of CTV Boost was found in 7F-H-IMRT plans despite lower ∆D_98% and ∆D_95%. Shifts in the S-I direction exerted the largest effect on CTV and CTV Boost. Regarding OARs, shifts in R, P, and I directions contributed to increasing the received dose. The 2A-VMAT plans performed better dose sparing, but had a higher robustness in a high-dose volume of the left lung and heart. The 2A-VMAT plans decreased the max dose of LAD but exhibited lower robustness. Conclusion: The 2A-VMAT plans showed higher sensitivity to position deviation. Shifts in the S-I direction exerted the largest effect for CTV and CTV Boost.

Two-year toxicity of simultaneous integrated boost in hypofractionated prone breast cancer irradiation: Comparison with sequential boost in a randomized trial

INTRODUCTION

A simultaneous integrated boost (SIB) leads to less acute toxicity. Less is known for late toxicity due to SIB. In this first and only randomized trial, two-years toxicity is analysed.

MATERIALS AND METHODS

Physician-assessed toxicity, using the LENT SOMA scale, and photographs, analysed with the BCCT.core software, was examined for 150 patients, randomized between SIB and sequential boost (SEB).

RESULTS

Differences in physician-assessed two-years toxicity and photographic analysis between SIB and SEB are very small and not significant.

CONCLUSION

There is no indication that a SIB leads to an excess in toxicity or worse cosmetic outcome at 2 years.

Impact of guideline changes on adoption of hypofractionation and breast cancer patient characteristics in the randomized controlled HYPOSIB trial

Purpose

Hypofractionated radiotherapy is the standard of care for adjuvant whole breast radiotherapy (RT). However, adoption has been slow. The indication for regional nodal irradiation has been expanded to include patients with 0–3 involved lymph nodes. We investigated the impact of the publication of the updated German S3 guidelines in 2017 on adoption of hypofractionation and enrollment of patients with lymph node involvement within a randomized controlled phase III trial.

Methods

In the experimental arm of the HYPOSIB trial (NCT02474641), hypofractionated RT with simultaneous integrated boost (SIB) was used. In the standard arm, RT could be given as hypofractionated RT with sequential boost (HF_seq), normofractionated RT with sequential boost (NF_seq), or normofractionated RT with SIB (NF_SIB). The cutoff date for the updated German S3 guidelines was December 17, 2017. Temporal trends were analyzed by generalized linear regression models. Multiple logistic regression models were used to investigate the influence of time (prior to/after guideline) and setting (university hospital/other institutions) on the fractionation patterns.

Results

Enrollment of patients with involved lymph nodes was low throughout the trial. Adoption of HF_seq increased over time and when using the guideline publication date as cutoff. Results of the multiple logistic regressions showed an interaction between time and setting. Furthermore, the use of HF_seq was significantly more common in university hospitals.

Conclusion

The use of HF_seq in the standard arm increased over the course of the HYPOSIB trial and after publication of the S3 guideline update. This was primarily driven by patients treated in university hospitals. Enrolment of patients with lymph node involvement was low throughout the trial.

Intensity Modulated Radiation Therapy (IMRT) With Simultaneously Integrated Boost Shortens Treatment Time and Is Noninferior to Conventional Radiation Therapy Followed by Sequential Boost in Adjuvant Breast Cancer Treatment: Results of a Large Randomized Phase III Trial (IMRT-MC2 Trial)

PURPOSE

In the modern era, improvements in radiation therapy techniques have paved the way for simultaneous integrated boost irradiation in adjuvant breast radiation therapy after breast conservation surgery. Nevertheless, randomized trials supporting the noninferiority of this treatment to historical standards of care approach are lacking.

METHODS

A prospective, multicenter, randomized phase 3 trial (NCT01322854) was performed to analyze noninferiority of conventional fractionated intensity modulated radiation therapy with simultaneous integrated boost (IMRT-SIB) to 3-D conformal radiation therapy with sequential boost (3-D-CRT-seqB) for breast cancer patients. Primary outcomes were local control (LC) rates at 2 and 5 years (noninferiority margin at hazard ratio [HR] of 3.5) as well as cosmetic results 6 weeks and 2 years after radiation therapy (evaluated via photo documentation calculating the relative breast retraction assessment [pBRA] score [noninferiority margin of 1.25]).

RESULTS

A total of 502 patients were randomly assigned from 2011 to 2015. After a median follow-up of 5.1 years, the 2-year LC for the IMRT-SIB arm was noninferior to the 3-D-CRT-seqB arm (99.6% vs 99.6%, respectively; HR, 0.602; 95% CI, 0.123-2.452; P = .487). In addition, noninferiority was also shown for cosmesis after IMRT-SIB and 3-D-CRT-seqB at both 6 weeks (median pBRA, 9.1% vs 9.1%) and 2 years (median pBRA, 10.4% vs 9.8%) after radiation therapy (95% CI, -0.317 to 0.107 %; P = .332). Cosmetic assessment according to the Harvard scale by both the patient and the treating physician as well as late-toxicity evaluation with the late effects normal tissues- subjective, objective, management, analytic criteria, a score for the evaluation of long-term adverse effects in normal tissue, revealed no significant differences between treatment arms. In addition, there was no difference in overall survival rates (99.6% vs 99.6%; HR, 3.281; 95% CI: -0.748 to 22.585; P = .148) for IMRT-SIB and 3-D-CRT-seqB, respectively.

CONCLUSIONS

To our knowledge, this is the first prospective trial reporting the noninferiority of IMRT-SIB versus 3-D-CRT-seqB with respect to cosmesis and LC at 2 years of follow-up. This treatment regimen considerably shortens adjuvant radiation therapy times without compromising clinical outcomes.

Intensity-Modulated Radiotherapy with Concomitant Boost After Breast Conserving Surgery: A Phase I-II Trial

Purpose

A concomitant boost (CB) in patients treated with postoperative radiotherapy after conservative surgery of invasive breast cancer (BC) has been suggested for treatment time reduction and therapy intensification. The aim of this analysis was to assess long-term tolerability of a CB in patients treated with postoperative intensity Modulated Accelerated RAdiotherapy (MARA).

Patients and Methods

In this phase I–II trial, 321 patients with intermediate-high risk BC (pT1-4 with at least one of the following characteristics: pre or perimenopausal status, pN2-3, positive or close margins) were enrolled. Patients were treated with forward-planned intensity modulated radiotherapy (IMRT) and CB. A total dose of 50 Gy (2 Gy/fraction) and 60 Gy (2.4 Gy/fraction) was prescribed to the whole breast and the tumor bed, respectively. The potential impact of hypertension, diabetes, smoking habit, alcohol consumption, chemotherapy, and hormone therapy on both skin and subcutaneous late toxicity-free survival (LTFS) was evaluated. Survival curves were calculated using the Kaplan–Meier method.

Results

Median follow-up was 52 months (range: 3–115). Regional node irradiation, adjuvant chemotherapy and hormonal therapy were prescribed to 29.3%, 65.4% and 81.0% of patients, respectively. Five-year G2 and G3 skin LTFS were 95.6% and 100.0%, respectively. Five-year G2 and G3 subcutaneous LTFS were 80.0% and 98.6%, respectively. Only diabetes showed a significant correlation with worse G3 subcutaneous LTFS (p: 0.024). Five-year loco-regional control, metastasis-free survival, disease-free survival, and overall survival were 98.0%, 91.8%, 89.7% and 96.3%, respectively.

Conclusion

IMRT combined with CB was associated with a low risk of > G2 late toxicities (0.0% and 1.4% for skin and subcutaneous tissue, respectively). The cumulative actuarial incidence of local recurrences was 2.0% despite the exclusion of low-risk patients. Our results suggest that CB is safe and effective in patients with intermediate-high risk BC.

Trial Registration

ClinicalTrials.gov: NCT03471741.

Acute toxicity of normofractionated intensity modulated radiotherapy with simultaneous integrated boost compared to three-dimensional conformal radiotherapy with sequential boost in the adjuvant treatment of breast cancer

BACKGROUND

Intensity-modulated radiotherapy (IMRT) improves dose homogeneity and late toxicity compared to simple tangential techniques in adjuvant whole-breast radiotherapy for patients with breast cancer. Simultaneous-integrated boost (SIB) radiotherapy shortens the overall treatment time and improves dose homogeneity. However, prospective randomized trials regarding IMRT with SIB for adjuvant radiotherapy in breast cancer are lacking.

METHODS

The IMRT-MC2 (MINT) trial is a phase III prospective randomized controlled trial comparing IMRT with SIB (Arm A: whole breast 28 × 1.8 Gy, Boost 28 × 2.3 Gy) to 3D-conformal radiotherapy with a sequential boost (Arm B: whole breast 28 × 1.8 Gy, boost 8 × 2 Gy) in patients with breast cancer after BCS. Indication for boost radiotherapy was defined as age < 70 years or age > 70 years with presence of additional risk factors. This is a retrospective analysis of acute toxicity at one of two trial sites.

RESULTS

Five hundred two patients were randomized, of which 446 patients were eligible for this analysis. There was no statistically significant difference in terms of any grade radiation dermatitis between the two treatment arms at the end of treatment (p = 0.26). However, radiation dermatitis grade 2/3 (29.1% vs. 20.1 and 3.5% vs. 2.3%) occurred significantly more often in Arm A (p = 0.02). Breast/chest wall pain at the first follow-up visit was significantly more common in patients treated on Arm B (p = 0.02).

CONCLUSIONS

Treatment on both arms was well tolerated, however there were some differences regarding radiodermatitis and breast pain. Further analyses are ongoing.

TRIAL REGISTRATION

clinicaltrials.gov , NCT01322854 , registered 24th March 2011.

Adjuvant hypofractionated radiotherapy with simultaneous integrated boost after breast-conserving surgery: results of a prospective trial

PURPOSE

We report results of a multicenter prospective single-arm phase II trial (ARO-2013-04, NCT01948726) of moderately accelerated hypofractionated radiotherapy with a simultaneous integrated boost (SIB) in patients with breast cancer receiving adjuvant radiotherapy after breast-conserving surgery.

METHODS

The eligibility criteria included unifocal breast cancer with an indication for adjuvant radiotherapy to the whole breast and boost radiotherapy to the tumor bed. The whole breast received a dose of 40 Gy and the tumor bed a total dose of 48 Gy in 16 fractions of 2.5 and 3 Gy, respectively. Radiotherapy could be given either as 3D conformal RT (3D-CRT) or as intensity-modulated radiotherapy (IMRT). The study was designed as a prospective single-arm trial to evaluate the acute toxicity of the treatment regimen. The study hypothesis was that the frequency of acute skin reaction grade ≥2 would be 20% or less.

RESULTS

From November 2013 through July 2014, 149 patients were recruited from 12 participating centers. Six patients were excluded, leaving 143 patients for analysis. Eighty-four patients (58.7%) were treated with 3D-CRT and 59 (41.3%) with IMRT. Adherence to the treatment protocol was high. The rate of grade ≥2 skin toxicity was 14.7% (95% confidence interval 9.8-21.4%). The most frequent grade 3 toxicity (11%) was hot flashes.

CONCLUSION

This study demonstrated low toxicity of and high treatment adherence to hypofractionated adjuvant radiotherapy with SIB in a multicenter prospective trial, although the primary hypothesis was not met.

Adjuvant breast inversely planned intensity-modulated radiotherapy with simultaneous integrated boost for early stage breast cancer : Results from a phase II trial

PURPOSE

To report early toxicity and 5‑year clinical outcomes of adjuvant breast inversely planned intensity-modulated radiotherapy with simultaneously integrated boost (IMRT-SIB) after breast-conserving surgery for early stage breast cancer patients.

PATIENTS AND METHODS

In all, 467 patients including 406 invasive breast cancer and 61 ductal carcinoma in situ (DCIS) were enrolled in a single institutional phase II trial. All patients underwent IMRT-SIB treatment to irradiate the whole breast and the tumor bed. Doses to whole breast and surgical bed were 45 and 60 Gy, respectively, delivered in 25 fractions over 5 weeks. The grade of maximum acute skin toxicity during treatment was recorded. Lung toxicity was noted within 6 months and patient-reported cosmetic outcomes were recorded at the 12 month follow-up after the end of radiotherapy. Clinical outcomes were assessed during follow-up.

RESULTS

Median follow-up time was 5.46 years. Median age was 46 years old (range 22-70 years old). No patient with DCIS had a local recurrence or distant metastasis. Among 406 patients with invasive breast cancer, the unadjusted 5‑year actuarial rate of locoregional control was 98.7% (95% confidence interval [CI] 97.5-100), and distant metastasis-free survival 98.7% (95% CI 97.4-100), respectively. Acute skin toxicity was recorded at grade 0-1 in 76.5% of patients, and grade 2 in 23.5% of patients. None of these patients had grade 3 or more than grade 3 skin toxicity. Grade 1 pneumonitis was found in 25.3% of patients. Assessment of patient reported cosmetic outcomes at the 12 month follow-up showed good or excellent outcome in 86.5% of cases.

CONCLUSIONS

The use of inversely planned IMRT-SIB as part of breast-conserving therapy results in optimal 5‑year tumor control and minor early toxicities.

Five-year survival outcomes of intensity-modulated radiotherapy with simultaneous integrated boost (IMRT-SIB) using forward IMRT or Tomotherapy for breast cancer

Intensity-modulated radiotherapy with simultaneous integrated boost (IMRT-SIB) reduces overall treatment duration and results in less radiotherapy (RT)-induced dermatitis. However, the use of traditional sequential approach or IMRT-SIB is still under debate since there is not enough evidence of long-term clinical outcomes. The present study investigated 216 patients who underwent breast conserving surgery (BCS) between 2010 and 2013. The median age was 51 years (range, 21-81 years). All patients received IMRT-SIB, 50.4 Gy at 1.8 Gy per fraction to the whole breast and 60.2 Gy at 2.15 Gy per fraction to the tumor bed by integral boost. Among 216 patients, 175 patients received post-operative RT with forward IMRT and 41 patients had Tomotherapy. The median follow-up was 6.4 years. Forty patients (97.6%) in the Tomotherapy arm and 147 patients (84%) in the IMRT arm developed grade 0-1 skin toxicity (P = 0.021). For the entire cohort, the 5-year and 7-year overall survival (OS) rates were 94.4% and 93.1% respectively. The 7-year distant metastasis-free survival rates were 100% vs 89.1% in the Tomotherapy and IMRT arm respectively (P = 0.028). In conclusion, Tomotherapy improved acute skin toxicity compared with forward IMRT-SIB. Chronic skin complication was 1.9%. IMRT-SIB resulted in good long-term survival.

Hybrid planning techniques for hypofractionated whole-breast irradiation using flattening filter-free beams

OBJECTIVE

The aim of this study was to assess the feasibility of flattening filter-free (FFF) photon beams in hybrid intensity-modulated radiation therapy (H-IMRT) and hybrid volumetric modulated arc therapy (H-VMAT) for left-sided whole-breast radiation therapy with a boost volume (RT) using a hypofractionated dose regimen.

PATIENTS AND METHODS

RT plans of 25 patients with left-sided early-stage breast cancer were created with H‑IMRT and H‑VMAT techniques under breath-hold conditions using 6‑MV FFF beams. In hybrid techniques, three-dimensional conformal radiotherapy (3DCRT) plans were kept as base-dose plans for the VMAT and IMRT plans. In addition, H‑IMRT in step-and-shoot mode was also calculated to assess its achievability with FFF beams.

RESULTS

All hybrid plans achieved the expected target coverage. H‑VMAT showed better coverage and homogeneity index results for the boost target (p < 0.002), while H‑IMRT presented better results for the whole-breast target (p < 0.001). Mean doses to normal tissues were comparable between both plans, while H‑IMRT reduced the low-dose levels to heart and ipsilateral lung (p < 0.05). H‑VMAT revealed significantly better results with regard to monitor units (MU) and treatment time (p < 0.001).

CONCLUSION

The 6‑MV FFF beam technique is feasible for large-field 3DCRT-based hybrid planning in whole-breast and boost planning target volume irradiation. For breath-hold patients, the H‑VMAT plan is superior to H‑IMRT for hypofractionated dose regimens, with reduced MU and treatment delivery time.

Dosimetric comparison of simultaneous integrated boost versus concomitant electron boost in radiotherapy treatment of breast cancer

Background

The aim of this study was to compare the dosimetric parameters and effects of simultaneous integrated boost (SIB) and traditional sequential electron boost, after helical tomotherapy, because of the lack of studies in this field in the current literature.

Methods

Computed tomographic data of 14 patients who received SIB in 2012–2015 were collected from Hong Kong Sanatorium & Hospital. New tomotherapy with SIB plans and tomotherapy with sequential boost plans were generated for each patient, and results were compared.

Results

Conformation number, mean dose, dose received by 95% volume (both sides), ipsilateral lung volume receiving 20 Gy (V20) and skin dose (right side) were found to be significantly better for SIB (p<0·05), however coverage index and gross target volume dose showed no significant difference, and heart dose was significantly higher for SIB on the right side.

Conclusion

Tomotherapy with SIB may be able to offer less organ at risk dose (except for the heart), while maintaining the ability to deliver adequate dose coverage.

Quality assessment of delineation and dose planning of early breast cancer patients included in the randomized Skagen Trial 1

BACKGROUND AND PURPOSE

To report on a Quality assessment (QA) of Skagen Trial 1, exploring hypofractionation for breast cancer patients with indication for regional nodal radiotherapy.

MATERIAL AND METHODS

Deviations from protocol regarding target volume delineations and dose parameters (Dmin, Dmax, D98%, D95% and D2%) from randomly selected dose plans were assessed. Target volume delineation according to ESTRO guidelines was obtained through atlas based automated segmentation and centrally approved as gold standard (GS). Dice similarity scores (DSC) with original delineations were measured. Dose parameters measured in the two delineations were reported to assess their dosimetric outcome.

RESULTS

Assessment included 88 plans from 12 centres in 4 countries. DSC showed high agreement in contouring, 99% and 96% of the patients had a complete delineation of target volumes and organs at risk. No deviations in the dosimetric outcome were found in 76% of the patients, 82% and 95% of the patients had successful coverage of breast/chestwall and CTVn_L2-4-interpectoral. Dosimetric outcomes of original delineation and GS were comparable.

CONCLUSIONS

QA showed high protocol compliance and adequate dose coverage in most patients. Inter-observer variability in contouring was low. Dose parameters were in harmony with protocol regardless original or GS segmentation.

Does an integrated boost increase acute toxicity in prone hypofractionated breast irradiation? A randomized controlled trial

BACKGROUND AND PURPOSE

The safety of a simultaneous integrated boost (SIB) in combination with prone hypofractionated whole-breast irradiation (WBI) was investigated.

MATERIALS AND METHODS

167 patients were randomized between WBI with a sequential boost (SeB) or SIB. All patients were treated in prone position to 40.05Gy in 15 fractions to the whole breast. In the control arm, a SeB of 10Gy in 4 fractions (negative surgical margins) or 14.88Gy in 6 fractions (transsection) was prescribed. In the experimental arm a SIB of 46.8 or 49.95Gy (negative and positive surgical margins, respectively) was prescribed.

RESULTS

Patient age was the only significantly different parameter between treatment arms with patients in the SIB arm being slightly older. In both arms, 6/83 patients developed moist desquamation. Grade 2/3 dermatitis was significantly more frequent in the SeB arm (38/83vs 24/83 patients, p=0.037). In the SIB and SeB arm, respectively, 36 patients (43%) and 51 patients (61%) developed pruritus (p=0.015). The incidence of oedema was lower in the SIB arm (59vs 68 patients), but not statistically significant (p=0.071).

CONCLUSIONS

The primary endpoint, moist desquamation, was not significantly different between treatment arms.

Simultaneous integrated boost (SIB) radiation therapy of right sided breast cancer with and without flattening filter - A treatment planning study

BACKGROUND

The aim of the study was to compare the two irradiation modes with (FF) and without flattening filter (FFF) for three different treatment techniques for simultaneous integrated boost radiation therapy of patients with right sided breast cancer.

METHODS

An Elekta Synergy linac with Agility collimating device is used to simulate the treatment of 10 patients. Six plans were generated in Monaco 5.0 for each patient treating the whole breast and a simultaneous integrated boost (SIB) volume: intensity modulated radiation therapy (IMRT), volumetric modulated arc therapy (VMAT) and a tangential arc VMAT (tVMAT), each with and without flattening filter. Plan quality was assessed considering target coverage, sparing of the contralateral breast, the lungs, the heart and the normal tissue. All plans were verified by a 2D-ionisation-chamber-array and delivery times were measured and compared. The Wilcoxon test was used for statistical analysis with a significance level of 0.05.

RESULTS

Significantly best target coverage and homogeneity was achieved using VMAT FFF with V95% = (98.7 ± 0.8) % and HI = (8.2 ± 0.9) % for the SIB and V95% = (98.3 ± 0.7) % for the PTV, whereas tVMAT showed significantly lowest doses to the contralateral organs at risk with a Dmean of (0.7 ± 0.1) Gy for the contralateral lung, (1.0 ± 0.2) Gy for the contralateral breast and (1.4 ± 0.2) Gy for the heart. All plans passed the gamma evaluation with a mean passing rate of (99.2 ± 0.8) %. Delivery times were significantly reduced for VMAT and tVMAT but increased for IMRT, when FFF was used. Lowest delivery times were observed for tVMAT FFF with (1:20 ± 0:07) min.

CONCLUSION

Balancing target coverage, OAR sparing and delivery time, VMAT FFF and tVMAT FFF are considered the preferable of the investigated treatment options in simultaneous integrated boost irradiation of right sided breast cancer for the combination of an Elekta Synergy linac with Agility and the treatment planning system Monaco 5.0.

Multibeam inverse intensity-modulated radiotherapy (IMRT) for whole breast irradiation: a single center experience in China

Purpose

To present the clinical experience in our cancer center with multibeam inverse intensity-modulated radiotherapy (IMRT) for early stage breast cancer (BC) patients with whole breast irradiation (WBI).

Methods

We retrospectively analyzed 622 patients with Stage 0 to III BC treated from 2008 to 2011 with wide local excision and WBI, using an inverse IMRT technique. All of the patients were prescribed a total dose of 50 Gy to the whole breast in 2-Gy fractions, followed by a tumor bed boost of 10 Gy in 5 fractions using an electron beam.

Results

Of all of the patients, 132 (21.2%) received whole breast plus regional lymph node (RLN) irradiation. 438 of 622 patients had records of acute skin toxicity based on common terminology criteria (CTC) for adverse events. Two hundred eighty (64%) patients had Grade 0/1 toxicity, 153 (35%) had Grade 2 and only 4 patients experienced grade 3 toxicity. Seventy patients (16%) had moist desquamation. Univariate analysis revealed that breast planning target volume was the only predictive factor for Grade ≥2 acute dermatitis (P = 0.002). After 4 years, 170 patients reported cosmetic results by self-assessment, of whom 151 (89%) patients reported good/excellent cosmetic results, and 17 (11%) patients reported fair assessments. For invasive cancer, the four-year rate of freedom from locoregional recurrence survival was 98.3%. Regarding carcinoma in situ, no patients experienced recurrence.

Conclusion

BC patients who underwent conservative surgery followed by inverse IMRT plan exhibited acceptable acute toxicities and clinical outcomes. Longer follow-up is needed.

Impact of tumour bed boost integration on acute and late toxicity in patients with breast cancer: A systematic review

The purpose of this systematic review was to summarise the evidence from studies investigating the integration of tumour bed boosts into whole breast irradiation for patients with Stage 0-III breast cancer, with a focus on its impact on acute and late toxicities. A comprehensive systematic electronic search through the Ovid MEDLINE, EMBASE and PubMed databases from January 2000 to January 2015 was conducted. Studies were considered eligible if they investigated the efficacy of hypo- or normofractionated whole breast irradiation with the inclusion of a daily concurrent boost. The primary outcomes of interest were the degree of observed acute and late toxicity following radiotherapy treatment. Methodological quality assessment was performed on all included studies using either the Newcastle-Ottawa Scale or a previously published investigator-derived quality instrument. The search identified 35 articles, of which 17 satisfied our eligibility criteria. Thirteen and eleven studies reported on acute and late toxicities respectively. Grade 3 acute skin toxicity ranged from 1 to 7% whilst moderate to severe fibrosis and telangiectasia were both limited to 9%. Reported toxicity profiles were comparable to historical data at similar time-points. Studies investigating the delivery of concurrent boosts with whole breast radiotherapy courses report safe short to medium-term toxicity profiles and cosmesis rates. Whilst the quality of evidence and length of follow-up supporting these findings is low, sufficient evidence has been generated to consider concurrent boost techniques as an alternative to conventional sequential techniques.

Image-guided volumetric arc radiotherapy of pancreatic cancer with simultaneous integrated boost: Optimization strategies and dosimetric results

PURPOSE

To introduce volumetric modulated arc therapy treatments (VMAT) with simultaneous integrated boost (SIB) for pancreatic cancer and describe dosimetric results on a large patient series.

METHODS AND MATERIALS

45 patients with pancreatic malignancies were treated with 18 MV single-arc VMAT. Image guidance was performed with daily online kilo-volt cone-beam computed tomography (CBCT). The conformity index (CI) and homogeneity index (HI) to the target volumes, PTV45Gy and PTV54Gy, and dose-volume indices to OARs from the QUANTEC task group were reported. The risk of clinical nephritis was evaluated using normal tissue complication probability (NTCP). Treatments were verified in-phantom with the Delta4 system.

RESULTS

Average CI was 1.06 with 95% confidence intervals (95% CI) of 0.97-1.22 for PTV45Gy and 1.17 (0.66-1.61) for PTV54Gy. HI of PTV54Gy was 1.06 (1.04-1.10). OAR constraints were achieved in all patients, except for kidneys V12Gy of 48 (35.4-72.3)%. NTCP of the kidneys was 0.98 (0.6-1.7)%. Kidneys V12Gy and V20Gy were inversely related to PTV54Gy CI and maximum dose. All in-phantom tests had gamma pass rates exceeding 95% with global 3% dose difference and 3 mm distance to agreement. Patient shifts measured with CBCT had 95% CI of -0.8, +0.8 in the RL, -0.7, +0.8 in the SI, and -0.8, +0.7 cm in the AP directions.

CONCLUSIONS

Dosimetric results of VMAT were excellent on PTVs and organs at risk. The kidneys represent the dose-limiting organ at risk for this technique. NTCP indicates that this technique is safe from radiation-induced side effects to the kidneys.

Comparison of breast simultaneous integrated boost (SIB) radiotherapy techniques

Purpose

To dosimetrically evaluate different breast SIB techniques with respect to target coverage and organs at risk (OARs) doses.

Methods

Four IMRT techniques were compared in 12 patients. Three techniques employ tangential whole breast irradiation with either two coplanar fields (T-2F), or four non-coplanar fields (T-NC), or one Volumetric Modulated Arc Therapy (T-VMAT) for the boost volume. The fourth technique is a fully-modulated VMAT technique (f-VMAT). Dosimetric parameters were compared for the boost and breast target volumes as well as OARs. Delivery efficiency was analysed based on number of monitor units (MUs) and estimated delivery time.

Results

T-VMAT and f-VMAT ranked highest with respect to integral assessment of boost and breast treatment quality measures. T-VMAT significantly outperformed f-VMAT with respect to ipsi-lateral lung and left-sided patients’ heart volumes ≥ 5 Gy (35 % ± 5 % vs. 52 % ± 6 % and 11 % ± 5 % vs. 22 % ± 6 %, respectively). f-VMAT significantly outperformed T-VMAT with respect to ipsi-lateral lung volume ≥ 20 Gy (13 % ± 2 % vs. 15 % ± 3 %) and heart volume ≥ 30 Gy in left breast cancer (0 % ± 0 % vs. 1 % ± 1 %). T-VMAT and f-VMAT needed 442 ± 58 and 1016 ± 152 MUs, respectively.

Conclusions

The hybrid T-VMAT is considered the technique of choice due to its balance of quality, efficiency and dose to OARs.

Tumor Bed Boost Integration during Whole Breast Radiotherapy: A Review of the Current Evidence

Radiation therapy delivered with hypofractionation, which involves the delivery of a higher dose per fraction in fewer fractions (generally with a lower total nominal dose) over a shorter overall treatment time, is an established therapeutic option at least for a selected group of early breast cancer patients after breast-conserving surgery. Optimal delivery of the tumor bed boost dose in terms of timing, fractionation, and total dose whenever a hypofractionated schedule is employed has yet to be established. We herein present a review of the current evidence on the role of boost integration in whole breast radiotherapy.

The impact of age on changes in quality of life among breast cancer survivors treated with breast-conserving surgery and radiotherapy

Background:

The purpose of the study was to determine the impact of young age on health-related quality of life (HRQoL) by comparing HRQoL of younger and older breast cancer patients, corrected for confounding, and of young patients and a general Dutch population.

Methods:

The population consisted of breast cancer survivors (stage 0-III) after breast-conserving surgery and radiotherapy. Health-related quality of life was prospectively assessed using the EORTC QLQ-C30 and QLQ-BR23 questionnaires. The association between age (⩽50; 51–70; ⩾70 years) and HRQoL over time was analysed with mixed modelling. The clinical relevance of differences between/within age groups was estimated with Cohen's D and consensus-based guidelines. The HRQoL data from the young patient cohort were compared with Dutch reference data at 3 years after radiotherapy.

Results:

A total of 1420 patients completed 3200 questionnaires. Median follow-up was 34 (range 6–70) months. Median age was 59 (range 28–85) years. Compared with older subjects, young women reported worse HRQoL in the first year after radiotherapy, but clinical relevance was limited. Three years after radiotherapy, HRQoL values in the younger group were equal to those in the reference population. Pain and fatigue after radiotherapy improved, with medium clinical relevance.

Conclusions:

Three years after radiotherapy for breast cancer, young age was not a risk factor for decreased HRQoL.