Accelerated Partial Breast Irradiation: A New Standard of Care?

Stereotactic body radiotherapy using CyberKnife versus interstitial brachytherapy in accelerated partial breast irradiation on left-sided breast: A comparison of dosimetric characteristics and preliminary clinical results

INTRODUCTION

We compared the dosimetric characteristics of the target and organs at risk (OARs) as well as the preliminary clinical outcomes between two accelerated partial breast irradiation (APBI) techniques.

METHODS

Forty-four patients diagnosed with left-sided early breast cancer who underwent APBI using either interstitial brachytherapy (IB) or stereotactic body radiation therapy (SBRT) with CyberKnife (CK) were retrospectively reviewed. The dosimetric parameters of the target and OARs were compared. Preliminary clinical outcomes, including tumor control and acute toxicity, were analyzed.

RESULTS

Treatment plans with CK demonstrated a better cardiac dose-sparing effect. Radiation doses to the heart at V150cGy for the CK and IB groups were 24.4 % and 60.4 %, respectively (p < 0.001), while the mean heart doses for the CK and IB groups were 107.4 cGy and 204 cGy, respectively (p < 0.001). The heart D1c.c. and the ipsilateral lung received a lower dose in the IB group, without any significant differences. The median follow-up time in the CK and IB groups was 28.6 and 61.3 months, respectively. No patients died from either breast cancer or cardiac events during follow-up. A locoregional recurrence event at the neck occurred in one patient within the IB group.

CONCLUSIONS

APBI planned by CK was shown to have a better dose-sparing effect on the heart, as well as better conformity and homogeneity to the target. CK is a non-invasive treatment which showed minimal acute toxicity and promising tumor control.

Evaluation of normal tissue complications in breast cancer re-irradiation: a meta-analysis study

BACKGROUND

In recent years, evidence has accumulated that a second method of conserving the breast from cancer with re-irradiation as part of treatment may be feasible and safe. Many oncologists are skeptical of breast re-irradiation due to concerns about late complications, so access to quantitative data on the prevalence of breast re-irradiation complications is very important. In this meta-analysis, we determine the prevalence of complications in normal tissue after breast re-irradiation.

MATERIALS AND METHODS

A search was done to recognize qualified studies using EMBASE, MEDLINE, PUBMED, Google Scholar, and Cochrane Collaboration Library electronic databases from 2000 to 2023. In total, ten primary studies were applied in this meta-analysis to estimate the prevalence of complications of disorders, skin fibrosis, and chest pain. Heterogeneity was investigated using the I2 index and the meta-regression to evaluate variables suspected of causing heterogeneity. Statistical analysis and synthesis were performed using Stata 17.

RESULTS

The average dose received by patients who underwent radiation therapy in two stages was 100.32 Gy, and in these patients, the prevalence of skin fibrosis and disorders was 47% (95% CI 71-22%; I2 = 96.76%, P < 0.001) and the prevalence of chest pain was 35% (95% CI 68-8%; I2 = 98.13%, P < 0.001).

CONCLUSIONS

There is little clinical information about the incidence of complications in breast re-irradiation therapy. This meta-analysis presents the prevalence of complications after breast re-irradiation to help radiation oncologists and physicists make better decisions.

Use of Radiation Therapy for the Treatment of Breast Cancer in 2019 Versus 2020

Purpose

The COVID-19 pandemic disrupted medical care. Little is known about how radiation therapy (RT) ordering behavior changed during the pandemic. This study examined (1) whether there was a change in the rate at which orders for lumpectomy were followed by orders for RT and (2) whether there was a change in the percentage of RT orders for hypofractionated (HF) RT rather than conventionally fractionated (CF) RT.

Methods and Materials

Prior authorization order data from 2019 and 2020, pertaining to patients with commercial and Medicare Advantage health plans, were reviewed to determine whether patients had an order for RT in the 90 days after lumpectomy and if it was for CF or HF RT. Univariate analyses were conducted using χ2 tests, and adjusted analyses were conducted using multivariate logistic regression, controlling for patient age, urbanicity, local median income, region, if the lumpectomy facility was academic, and if the lumpectomy facility was a hospital.

Results

In 2019, 47.7% of included lumpectomy orders (2200/4610) were followed by an RT order within 90 days, in contrast to 45.6% (1944/4263) in 2020 (P = .048). Of the RT orders meeting this study's definition of CF or HF, 75.3% of orders placed in 2019 (1387/1843) and 79.0% of orders placed in 2020 (1261/1597) were for HF (P = .011). Adjusted analysis found patients receiving a lumpectomy order in the first quarter of 2020 had significantly reduced odds (odds ratio, 0.84; 95% CI, 0.71-0.99) of receiving an order for RT after lumpectomy, relative to those with orders placed in the first quarter of 2019. Adjusted analysis likewise found significant evidence of increased use of HF RT during the pandemic.

Conclusions

In the population examined, physicians were less likely to order RT after lumpectomy in 2020 than in 2019, and if they did, were more likely to order HF RT.

Factors Associated With Cosmetic Outcomes After Treatment With a Novel Form of Breast Intraoperative Radiation Therapy

INTRODUCTION

Precision breast intraoperative radiation therapy (PB-IORT) incorporates computed tomography-guided treatment planning and high dose rate brachytherapy to deliver a single dose of highly conformal radiational therapy. The purpose of this study is to determine factors associated with poor cosmetic outcomes after treatment with PB-IORT.

METHODS

The study included all consecutive participants enrolled in an ongoing phase II clinical trial that had completed a minimum of 12 mo of follow-up. A poor cosmetic outcome was defined as scoring "fair" or "poor" on the Harvard Cosmesis evaluation, or "some" or "very much" on any of the three general cosmesis categories. Statistical analysis was performed utilizing R.

RESULTS

The final cohort included 201 participants, of which 181 (90%) had an overall good/excellent cosmetic outcome. Group 1 consisted of 162 (81%) participants who reported only excellent/good cosmetic outcomes. Group 2 consisted of 39 (19%) participants who reported some aspect of a poor cosmetic outcome. On multivariable analysis, participants with ductal carcinoma in situ were significantly more likely to experience a poor cosmetic outcome (odds ratio 2.45, 95% confidence interval 1.03-5.82, P = 0.04), and those who received subsequent whole breast irradiation were also more likely to have a poor cosmetic outcome (odds ratio 10.20, 95% confidence interval CI 1.04-99.95, P = 0.04).

CONCLUSIONS

Patients with need for further radiation after PB-IORT are at increased risk for a poor cosmetic outcome. Larger balloon volume and distance between the skin do not have deleterious effects on cosmetic outcomes.

Mediastinal irradiation and valvular heart disease

Anticancer therapy has the potential to cause unwanted cardiovascular side effects. Utilization of radiation therapy to treat tumors near the heart can result in radiation-induced valvular heart disease among other cardiovascular pathologies. The aim of this review is to describe the epidemiology, pathophysiology, risk prediction, non-invasive imaging modalities and management of radiation-induced valvular heart disease with a focus on pre-operative risk assessment and contemporary treatment options.

Risk factors and specific cancer types of second primary malignancies in patients with breast cancer receiving adjuvant radiotherapy: a case-control cohort study based on the SEER database

Patients with breast cancer can survive and live a long, cancer-free life; however, late complications of treatment, such as second primary malignancies (SPMs), have emerged as a competing cause of death and morbidity. We conducted a long-term population-based cohort study to identify the risk factors for SPMs and specific secondary cancer types after various latency periods of irradiated breast cancer. Cox proportional hazards regression was used to calculate the hazard ratio (HR) and 95% confidence interval (95% CI) for independent risk factors for SPM. We also calculated the HR of each specific cancer type and the latency time to specific SPMs. The risk of SPM was statistically significantly higher in patients with adjuvant RT than in patients without adjuvant RT (adjusted HR [aHR]: 1.105, 95% CI: 1.013-1.206). Compared with the control group, the case group had significantly increased risks of contralateral breast cancer (aHR: 1.268, 95% CI: 1.112-1.445), lung cancer (aHR: 1.218, 95% CI: 1.049-1.565), and urinary system cancer (aHR: 1.702, 95% CI: 1.140-2.543). Adjuvant RT for breast cancer increases the risk of SPM. Contralateral breast cancer, lung cancer, and bladder cancer were significant SPMs after breast RT, although the cumulative risk of SPM was low, at approximately 6, 10, and 13 cancers per 1000 women with irradiated breasts at latency periods of 5, 10, and 15 years, respectively, after breast RT.

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.

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.

A meta-analysis of the efficacy and safety of accelerated partial breast irradiation versus whole-breast irradiation for early-stage breast cancer

OBJECTIVE

This meta-analysis evaluated the efficacy and safety of accelerated partial breast irradiation versus whole-breast irradiation for early-stage breast cancer after breast-conserving surgery.

MATERIALS AND METHODS

A systematic search of PubMed, Embase, and the Cochrane libraries was performed according to the PRISMA statement the last 10 years to April 7, 2020 to identify the randomized controlled trials of APBI versus WBI for treating patients with early-stage breast cancer. Two independent observers evaluated the identified studies. The obtained data were analyzed using the RevMan 5.3 software.

RESULTS

A total of 10 randomized controlled trials involving 15,500 patients with early-stage breast cancer were selected according to the inclusion and exclusion criteria and included in this meta-analysis. In this meta-analysis, we included ten studies that reported local recurrence and found significant differences in local recurrence rates (HR = 1.46; 95% CI 1.20-1.79, P = 0.0002). Further analysis showed that this difference may be related to the choice of treatment methods. No differences in distant metastasis, breast cancer deaths, contralateral breast cancer, disease-free survival, and overall survival rates were observed between WBI and APBI groups. There was no significant difference in late toxicity, cosmetic outcomes and quality of life between the two groups, the compliance and tolerance of the patients were well. Compared to whole breast irradiation, accelerated partial breast irradiation significantly reduced serious (≥ grade 2) early toxicities, especially regarding acute skin toxicity.

CONCLUSIONS

The analysis showed that patients receiving APBI had a higher local recurrence rate, but no differences in distant metastasis, breast cancer deaths, contralateral breast cancer, disease-free survival, and overall survival rates.

Moderate hypofractionation remains the standard of care for whole-breast radiotherapy in breast cancer: Considerations regarding FAST and FAST-Forward

Moderate hypofractionation is the standard of care for adjuvant whole-breast radiotherapy after breast-conserving surgery for breast cancer. Recently, 10-year results from the FAST and 5‑year results from the FAST-Forward trial evaluating adjuvant whole-breast radiotherapy in 5 fractions over 5 weeks or 1 week have been published. This article summarizes recent data for moderate hypofractionation and results from the FAST and FAST-Forward trial on ultra-hypofractionation. While the FAST trial was not powered for comparison of local recurrence rates, FAST-Forward demonstrated non-inferiority for two ultra-hypofractionated regimens in terms of local control. In both trials, the higher-dose experimental arms resulted in elevated rates of late toxicity. For the lower dose experimental arms of 28.5 Gy over 5 weeks and 26 Gy over 1 week, moderate or marked late effects were similar in the majority of documented items compared to the respective standard arms, but significantly worse in some subdomains. The difference between the standard arm and the 26 Gy of the FAST-Forward trial concerning moderate or marked late effects increased with longer follow-up in disadvantage of the experimental arm for most items. For now, moderate hypofractionation with 40–42.5 Gy over 15–16 fractions remains the standard of care for the majority of patients with breast cancer who undergo whole-breast radiotherapy without regional nodal irradiation after breast-conserving surgery.