Outcomes After Accelerated Partial Breast Irradiation in Women With Triple Negative Subtype and Other "High Risk" Variables Categorized as Cautionary in The ASTRO Guidelines

Indian Brachytherapy Society consensus recommendations for brachytherapy in breast cancer

Purpose

This consensus statement of Indian Brachytherapy Society (IBS) aims to generate practical and reproducible guidelines allowing for direct implementation in the Indian scenario.

Material and methods

IBS board of directors appointed a panel of physicians with expertise in breast cancer and, in particular, breast brachytherapy, to develop a consensus statement. First, a literature review on breast brachytherapy was conducted, focusing on randomized trials, prospective studies, and multi-institutional series. Then, guidelines were drafted based on authors' consensus according to Indian scenario.

Results

IBS advocate accelerated partial breast irradiation (APBI) with brachytherapy following breast conservation surgery (BCS) for suitable groups of patients. Also, IBS recommends brachytherapy as the preferred technique for patients requiring tumor bed boost. Multi-catheter interstitial brachytherapy (MIB) is suitable in most situations, except for a large tumor to breast ratio, and type 2 oncoplasty or higher performed. For best cosmesis, IBS recommends a minimum 3-week gap between chemotherapy and APBI.

Conclusions

Brachytherapy continues to be an established technique for APBI as well as boost in appropriately selected patients with early breast cancer (EBC). As breast brachytherapy is an underutilized therapy in the Indian context, this article will hopefully encourage the readers to use its clinical potential in the suitable groups of patients.

Concurrent chemotherapy with partial breast irradiation in triple negative breast cancer patients may improve disease control compared with sequential therapy

Purpose

To report outcomes on a subset of patients with triple negative breast cancer (TNBC) treated on prospective trials with post-lumpectomy partial breast irradiation and concurrent chemotherapy (PBICC) and compare them to a retrospectively assessed similar cohort treated with whole breast irradiation after adjuvant chemotherapy (WBIaC).

Methods and materials

Women with T1-2, N0-1 invasive breast cancer with ≥ 2mm lumpectomy margins were offered therapy on one of two PBICC trials. PBI consisted of 40.5 Gy in 15 daily 2.7 Gy fractions delivered concurrently with the first 2 cycles of adjuvant chemotherapy. The comparison cohort received WBI to a median dose of 60.7 Gy, (including boost, range 42.5 - 66 Gy), after completion of non-concurrent, adjuvant chemotherapy. We evaluated disease-free survival (DFS), and local/loco-regional/distant recurrence-free survival (RFS). We compared survival rates using Kaplan-Meier curves and log-rank test of statistical significance.

Results

Nineteen patients with TNBC were treated with PBICC on prospective protocol, and 49 received WBIaC. At a median follow-up of 35.5 months (range 4.8-71.9), we observed no deaths in the PBICC cohort and 2 deaths in the WBIaC cohort (one from disease recurrence). With a median time of 23.4 (range 4.8 to 47) months, there were 7 recurrences (1 nodal, 4 local, 4 distant), all in the WBIaC group. At 5 years, there was a trend towards increased local RFS (100% vs. 85.4%, p=0.17) and loco-regional RFS (100% vs. 83.5, p=0.13) favoring the PBICC cohort. There was no significant difference in distant RFS between the two groups (100% vs. 94.4%, p=0.36). Five-year DFS was 100% with PBICC vs.78.9% (95% CI: 63.2 to 94.6%, p=0.08) with WBIaC.

Conclusion

This study suggests that PBICC may offer similar and possibly better outcomes in patients with TNBC compared to a retrospective cohort treated with WBIaC. This observation is hypothesis-generating for prospective trials.

Partial breast irradiation: An updated consensus statement from the American brachytherapy society

PURPOSE

In recent years, results with mature follow-up have been reported for several Phase III trials randomizing women to receive whole breast irradiation (WBI) versus varying modalities of partial breast irradiation (PBI). It is important to recognize that these methods vary in terms of volume of breast tissue treated, dose per fraction, and duration of therapy. As such, clinical and technical guidelines may vary among the various PBI techniques.

METHODS

Members of the American Brachytherapy Society with expertise in PBI performed an extensive literature review focusing on the highest quality data available for the numerous PBI options offered in the modern era. Data were evaluated for strength of evidence and published outcomes were assessed.

RESULTS

The majority of women enrolled on randomized trials of WBI versus PBI have been age >45 years with tumor size <3 cm, negative margins, and negative lymph nodes. The panel also concluded that PBI can be offered to selected women with estrogen receptor negative and/or Her2 amplified breast cancer, as well as ductal carcinoma in situ, and should generally be avoided in women with extensive lymphovascular space invasion.

CONCLUSIONS

This updated guideline summarizes published clinical trials of PBI methods. The panel also highlights the role of PBI for women facing special circumstances, such as history of cosmetic breast augmentation or prior breast irradiation, and discusses promising novel modalities that are currently under study, such as ultrashort and preoperative PBI. Updated consensus guidelines are also provided to inform patient selection for PBI and to characterize the strength of evidence to support varying PBI modalities.