Preliminary Results of Multi-Institutional Phase 1 Dose Escalation Trial Using Single-Fraction Stereotactic Partial Breast Irradiation for Early Stage Breast Cancer

PURPOSE

We report on our early experience of our prospective multicenter phase 1 dose- escalation study of single-fraction stereotactic partial breast irradiation (S-PBI) for early stage breast cancer after partial mastectomy using a robotic stereotactic radiation system.

METHODS AND MATERIALS

Thirty women with in situ or invasive breast cancer stage 0, I, or II with tumor size <3 cm treated with lumpectomy were enrolled in this phase 1 single-fraction S-PBI dose-escalation trial. Women received either 22.5, 26.5, or 30 Gy in a single fraction using a robotic stereotactic radiation system. The primary outcome was to reach tumoricidal dose of 30 Gy in a single fraction to the lumpectomy cavity without exceeding the maximum tolerated dose. Secondary outcomes were to determine dose-limiting toxicity and cosmesis. Tertiary goals were ipsilateral breast recurrence rate, distant disease-free interval, recurrence-free survival, and overall survival.

RESULTS

From June 2016 to January 2021, 11, 8, and 10 patients were treated to doses of 22.5, 26.5, or 30 Gy in a single fraction, respectively, with median follow-up being 47.9, 25.1, and 16.2 months. No patients experienced acute (<90 days) grade 3 or higher treatment-related toxicity, and maximum tolerated dose was not reached. There were 2 delayed grade 3 toxicities. Four patients (13.8%) developed fat necrosis across all 3 cohorts, which compares favorably with results from other PBI trials. No dose cohort had a statistically significant cosmetic detriment from baseline to 12 months or 24 months follow-up by patient- or physician-reported global cosmetic scores. There were no reports of disease recurrence.

CONCLUSIONS

This phase 1 trial demonstrates that S-PBI can be used to safely escalate dose to 30 Gy in a single fraction with low toxicity and without detriment in cosmesis relative to baseline.

Predictive factors for persistent and late radiation complications in breast cancer survivors

PURPOSE

With improved diagnostic techniques and treatments of breast cancer, overall survival times are longer, giving more opportunity for normal tissue complications of treatment to manifest. Radiation late effects (RLEs) could have profound long-term impacts on the quality of life of the survivors. The aim of this study was to identify predictive factors influencing timing and types of complications in patients referred to the Adult Radiation Late Effects Clinic (ARLEC).

METHODS

In a period of 16 years, 296 breast cancer patients were referred to the ARLEC. The clinical records were retrospectively studied to collect epidemiologic, medical and treatment data. Associations were sought between candidate predictive factors and time to the first complication after radiation treatment (RT) completion (primary outcome), and pain or swelling (secondary outcomes) using univariable and multivariable linear and logistic regression analyses. All analyses were performed in SAS, version 9.4.

RESULTS

All patients were female with a mean age of 56.3 years. The first treatment-related complication occurred after a median of 3 months. Patients were followed at ARLEC for a median of 18 months. Older age and delay from surgery to RT (S-RT delay) were associated with earlier onset of complications (both p < 0.001). The most common complications were breast pain (62.1%) and swelling (45.9%). Histology and RT boost were associated with pain (p = 0.035 and 0.013). RT boost and S-RT delay on the other hand were associated with swelling (p = 0.013 and 0.005).

CONCLUSIONS

Clinical factors identified could help recognize the patients at high risk for developing RLEs and alert physicians to initiate earlier diagnostic and therapeutic measures.

Incidence and Outcome of Breast Biopsy Procedures During Follow-up After Treatment for Breast Cancer

Importance

No comprehensive data are available regarding the frequency of breast biopsies performed during follow-up of treatment for invasive breast cancer.

Objective

To determine how often patients treated for breast cancer require breast biopsies during follow-up.

Design, Setting, and Participants

This nationwide population-based cohort study included 41 510 patients 64 years or younger in a commercial insurance database and 80 369 patients 66 years or older in the Surveillance, Epidemiology, and End Results (SEER)-Medicare database. Patients were diagnosed with incident invasive breast cancer (stages I-III) from January 1, 2000, through December 31, 2011. Diagnosis and procedural codes were used to identify biopsy rates during follow-up. Data were analyzed from March 3 through October 3, 2017.

Main Outcomes and Measures

Cumulative incidence and adjusted risk of breast biopsy and subsequent breast cancer treatment were calculated using the Kaplan-Meier method and Cox proportional hazards regression. All statistical tests were 2 sided.

Results

Among the 121 879 patients in the study population, 5- and 10-year overall incidences of breast biopsy were 14.7% and 23.4%, respectively, in the commercial insurance cohort and 11.8% and 14.9%, respectively, in the SEER-Medicare cohort. The 5-year estimated incidence of breast biopsy was higher among women treated with brachytherapy (24.0% in the commercial insurance and 25.0% in the SEER-Medicare cohorts) than among those treated with whole-breast irradiation (16.7% in the commercial insurance and 15.1% in the SEER-Medicare cohorts) and persisted after multivariate adjustment in the commercial insurance (hazard ratio [HR], 1.53; 95% CI, 1.38-1.70; P < .001) and SEER-Medicare (HR, 1.76; 95% CI, 1.63-1.91; P < .001) cohorts. Adjuvant chemotherapy use (HR, 1.31; 95% CI, 1.25-1.37; P < .001) and patient age (>85 vs 66-69 years; HR, 0.40; 95% CI, 0.36-0.44; P < .001) in the SEER-Medicare cohort and endocrine therapy in the commercial insurance (HR, 0.88; 95% CI, 0.82-0.93; P < .001) and SEER-Medicare (HR, 0.91; 95% CI, 0.85-0.97; P = .002) cohorts were independently associated with biopsy. After unilateral mastectomy, the estimated 5-year contralateral breast biopsy rates were 10.4% and 7.7% in the commercial insurance and SEER-Medicare cohorts, respectively. Of the patients with breast biopsy, 1239 of 4158 patients (29.8%) in the commercial insurance cohort and 2258 of 9747 patients (23.2%) in the SEER-Medicare cohort underwent subsequent cancer treatment.

Conclusions and Relevance

These data on the need for breast biopsies during follow-up and subsequent treatments from a large cohort of women with commercial insurance and Medicare can be used in the context of therapy-planning discussions and survivorship expectations for patients with breast cancer.

A multi-institutional analysis of intraoperative radiotherapy for early breast cancer: Does age matter?

BACKGROUND

Single-session intraoperative radiation therapy (IORT) minimizes treatment demands associated with traditional whole breast radiation therapy (WBRT) but outcomes on local disease control and morbidity among the elderly is limited.

METHODS

A multi-institutional retrospective registry was established from 19 centers utilizing IORT from 2007 to 2013. Patient, tumor, and treatment variables were analyzed for ages <70 and ≥70.

RESULTS

We evaluated 686 patients (<70 = 424; ≥70 = 262) who were margin and lymph node negative. Patients <70 were more likely to have longer operative time, oncoplastic closure, higher rates of IORT used as planned boost, and receive chemotherapy and post-operative WBRT. Wound complication rates were low and not significantly different between age groups. Median follow-up was 1.06 (range 0.51-1.9) years for < 70 and 1.01 (range 0.5-1.68) years for ≥ 70. There were 5 (0.73%) breast recurrences (4 in <70 and 1 ≥ 70, p = 0.65) and no axillary recurrences during follow-up.

CONCLUSIONS

IORT was associated with a low rate of wound complication and local recurrence on short-term follow-up in this cohort.

Long term radiographic findings of breast brachytherapy: Implications of surgical volume

PURPOSE

Little is known about long-term radiographic findings after treatment with accelerated partial breast irradiation (APBI).

METHODS

Univariate and multivariate analysis of factors leading to formation and resolution of seroma were performed in patients treated with lumpectomy and APBI.

RESULTS

Post-treatment images of 129 patients were reviewed by one radiologist. Median surgical excision volume was 108.9 cc (range 20.5-681.9). Primary mode of imaging was mammogram. Median time from end of RT to first and last surveillance image was 6 and 54 months, respectively. Median number of images was 7 (range 3-12). Seroma was identified in 98 (76%) patients, with median maximum diameter of 3.9 cm. Forty (41%) patients experienced resolution of seroma, at a median time of 29 months (range 6-74). On univariate analysis, surgical excision volume was associated with seroma formation, and tumor stage and margin re-excision were significant on univariate and multivariate analysis. No factors were associated with seroma resolution.

CONCLUSION

Seroma formation after APBI resolves around 2.5 years for many patients, but persists for others possibly due to primary tumor and surgical excision volumes. With revised criteria on the definition of positive margins, smaller volumes may lead to decreased risk of seroma formation for future patients.

Tumoral Calcinosis: An Uncommon Cause for a Mass in a Reconstructed Breast

Tumoral calcinosis is a rare clinical and histopathological syndrome whose exact etiology is unknown. We present a case of a 57-year-old woman who presents with a painful lump in her right chest after bilateral breast reconstructions for bilateral asynchronous breast cancers. It is important to be aware of all possible differential diagnoses in a patient presenting with a chest mass after mastectomy and reconstruction for breast cancer as not all lesions of this type represent recurrent cancer.