A comparison of long-term clinical outcomes of accelerated partial breast irradiation using interstitial brachytherapy as per GEC-ESTRO, ASTRO, updated ASTRO, and ABS guidelines

Intraoperative Radiotherapy Is Not a Better Alternative to Whole Breast Radiotherapy as a Therapeutic Option for Early-Stage Breast Cancer

Objective

Intraoperative radiotherapy (IORT) in early-stage breast cancer has been studied over the years. However, it has not been demonstrated whether IORT is more suitable as a therapeutic option for early-stage breast cancer than whole breast radiotherapy (WBRT). Therefore, we performed a meta-analysis to compare the efficacy and safety of IORT to those of WBRT as therapeutic options for early-stage breast cancer patients receiving breast-conserving surgery (INPLASY2020120008).

Methods

PubMed, Embase, and Cochrane Library databases were searched from inception to October 2021. Computerized and manual searches were adopted to identify eligible randomized control trials from online databases. Risk ratio (RR) and 95% confidence intervals (CI) were calculated by random-effect models to assess the relative risk. Potential publication bias was quantified by Begg’s and Egger’s tests.

Results

Based on our inclusion criteria, 10 randomized control trials involving 5,698 patients were included in this meta-analysis. This meta-analysis showed that the IORT group was associated with a higher local recurrence risk (RR = 2.111, 95% CI, 1.130–3.943, p = 0.0191), especially in the long-term follow-up subgroup or published after 2020 subgroup or Caucasian subgroup (RR = 2.404, 95% CI, 1.183–4.885, p = 0.0154). Subgroup analysis showed that the IORT group had a higher recurrence risk than the WBRT group in the polycentric randomized controlled trial subgroup (RR = 1.213, 95% CI, 1.030–1.428, p = 0.0204). Pooled analysis showed that there was no statistically significant difference in overall survival, recurrence-free survival, distant metastasis-free survival, and cancer-specific survival between IORT and WBRT groups. Additionally, the risk of skin toxicity was reduced, but the incidences of fat toxicity, edema, and scar calcification were significantly increased in the patients who underwent IORT in comparison to those who underwent WBRT.

Conclusion

This meta-analysis revealed that IORT was not a better alternative to WBRT. More large-scale and well-designed clinical trials with longer follow-up periods are encouraged to further investigate the value of IORT.

Systematic Review Registration

https://inplasy.com/inplasy-2020-12-0008/.

Increased Risk for Ipsilateral Breast Tumor Recurrence in Invasive Lobular Carcinoma after Accelerated Partial Breast Irradiation Brachytherapy

BACKGROUND

The suitability criteria for accelerated partial breast irradiation (APBI) from the American Brachytherapy Society (ABS), American Society for Radiation Oncology (ASTRO), and The Groupe Européende Curiethérapie European SocieTy for Radiotherapy & Oncology (GEC-ESTRO) have significant differences.

MATERIALS AND METHODS

This is a single institution retrospective review of 946 consecutive patients with invasive breast cancer who underwent lumpectomy and APBI intracavitary brachytherapy from 2003 to 2018. Overall survival (OS), breast cancer-specific survival (BCSS), relapse-free survival (RFS), and ipsilateral breast tumor recurrence (IBTR) were estimated with Kaplan-Meier method.

RESULTS

Median follow-up time was 60.2 months. Median age was 68 years (46-94 years). The majority of patients had estrogen receptor (ER)-positive disease (94%). There were 821 (87%) cases of invasive ductal carcinoma and 68 cases (7%) of invasive lobular carcinoma (ILC). The 5-year OS, BCSS, RFS, and IBTR were 93%, 99%, 90%, and 1.5%, respectively. Upon univariate analysis, ILC (hazard ratio [HR], 4.6; p = .008) and lack of nodal evaluation (HR, 6.9; p = .01) were risk factors for IBTR. The 10-year IBTR was 2.5% for IDC and 14% for ILC. While the ABS and ASTRO criteria could not predict IBTR, the GEC-ESTRO intermediate risk group was associated with inferior IBTR (p = .04) when compared to both low risk and high risk groups. None of the suitability criteria was able to predict RFS.

CONCLUSION

These results show that APBI is an effective treatment for patients with invasive breast cancer. Expansion of the current eligibility criteria should be considered, although prospective validation is needed. Caution is required when considering APBI for patients with ILC.

IMPLICATIONS FOR PRACTICE

In a large retrospective review of 946 patients with early breast cancer treated with partial mastectomy and accelerated partial breast irradiation (APBI) intracavitary brachytherapy, this study demonstrates durable local control. Patients deemed unsuitable or high risk by the American Brachytherapy Society, American Society for Radiation Oncology, and European Society for Radiotherapy and Oncology guidelines were not at increased risk for ipsilateral breast tumor recurrence (IBTR), suggesting that expansion of the current criteria should be considered. Importantly, however, these results demonstrate that caution should be taken when considering APBI for patients with invasive lobular carcinoma, as these patients had relatively high risk for IBTR (10-year IBTR, 14%).

Patient-reported quality of life with interstitial partial breast brachytherapy and external beam whole breast radiotherapy: a comparison using propensity-score matching

Purpose

The aim of this study was to compare patient-reported quality of life (QOL) scores after accelerated partial breast irradiation (APBI) using interstitial brachytherapy vs. external beam whole breast radiotherapy (WBRT) for breast cancer.

Material and methods

Women with breast cancer treated with WBRT or APBI after breast conservation surgery were enrolled in this prospective study. Single cross-sectional QOL assessment was performed using EORTC QLQ-C30 and BR-23 questionnaires. Patients treated with APBI were propensity-score matched to similar cohort of patients treated with WBRT. QOL scores were analyzed for the entire unmatched cohort and compared between the two matched cohorts using Student’s two-tailed t-test. P-value of < 0.05 was considered statistically significant, and a 10-point difference between mean scores was considered clinically meaningful.

Results

A total of 64 APBI patients were matched with 99 WBRT patients out of the entire study cohort of 320 cases. QOL scores for functional scales of QLQ-C30 were similar between the two groups for both matched and unmatched cohorts, while symptom scores of QLQ-C30 did not show any clinically significant difference. Functional scales of BR-23 did not show any clinical or statistically significant difference. Among symptom scales of BR-23, scores were similar for APBI and WBRT groups except for a worse score of “upset by hair loss” sub-scale in the brachytherapy group of the matched cohort (51.9 vs. 22.7, p = 0.006).

Conclusions

Patients undergoing APBI reported similar QOL compared to WBRT when matched for various factors.