Treatment patterns for ductal carcinoma in situ with close or positive mastectomy margins

[Overall survival and survival without local recurrence in case of radiotherapy of the tumor bed of ductal carcinomas in situ of the breast: Review of the literature]

INTRODUCTION

Carcinomas in situ represent more than 15 to 20% of breast cancers. Radiotherapy of whole breast is part of the therapeutic standard and follows surgery. However, the indication of tumor bed irradiation is still controversial and heterogeneous according to international practice even though it is a very frequent clinical situation. The aim of this study is to define the indications of tumor bed irradiation in the context of ductal carcinomas in situ and to discuss accelerated partial irradiation of the breast.

METHOD

The selected papers were published between 2015 and 2020 and included as MeSH terms "ductal carcinoma in situ" and "boost" for the analysis of tumor bed irradiation, and "ductal carcinoma in situ" and "accelerated partial breast irradiation" for the analysis of accelerated partial irradiation.

RESULTS

Boost was more often performed when risk factors for local recurrence were present, such as age less than 40 or 50 years old, clinical mode of detection, tumor size greater than 15 to 20mm, high nuclear grade, presence of necrosis, positive or insufficient surgical margins, associated atypical hyperplastic lesions, and lobular carcinoma in situ. Accelerated partial irradiation is an option for favorable or intermediate prognosis CCIS, further studies involving more patients are required.

CONCLUSION

Radiotherapy of the mammary gland in the context of DCIS has shown its effectiveness in terms of local and locoregional control of the disease, thus reducing in situ and infiltrating recurrences. However, the indication of operating bed irradiation is still debated, and the practice is very heterogeneous depending on the country. Another possible alternative for patients with a favorable prognosis and a small tumor bed volume would be IPA.

Ductal carcinoma in situ in patients younger than 30 years: differences in adjuvant endocrine therapy and outcomes

PURPOSE

To use the National Cancer Database to assess treatment patterns in very young women with ductal carcinoma in situ (DCIS) given their propensity for higher risk features and increased risk of recurrence.

METHODS

We used the NCDB to identify female patients who underwent surgery for a first cancer diagnosis of DCIS within three different age groups: ≤30, 31-50, and >50. Demographic information, tumor characteristics, and initial treatment patterns were characterized and compared. Univariable and multivariable logistic regression of individuals with hormone-receptor-positive disease who underwent breast-conserving surgery (BCS) was conducted to assess for group differences in adjuvant endocrine therapy utilization. Survival analysis was conducted via Kaplan-Meier method and Cox regression.

RESULTS

We identified 236,832 patients meeting inclusion criteria. Individuals in the youngest group were more likely to be a minority, had better Charlson-Deyo scores, lived further from their treatment facility, and were less often insured. This group also had more unfavorable tumor features and were more likely to undergo bilateral mastectomy. In subgroup analysis of patients with hormone-receptor-positive disease who underwent BCS, the youngest group was significantly less likely to have received endocrine therapy. There was also a trend toward worse overall survival in the youngest group.

CONCLUSION

We report differences in demographics, tumor characteristics, and treatment of very young women with DCIS. Given the known reduction in recurrence with use of adjuvant endocrine therapy, there may be room for increasing therapy rates or otherwise altering guidelines for treatment of young women with hormone-receptor-positive DCIS who undergo BCS.

The Assisi Think Tank Meeting Survey of post-mastectomy radiation therapy in ductal carcinoma in situ: Suggestions for routine practice

BACKGROUND

Risk factors for local recurrence after mastectomy in ductal carcinoma in situ (DCIS) emerged as a grey area during the second "Assisi Think Tank Meeting" (ATTM) on Breast Cancer.

AIM

To review practice patterns of post-mastectomy radiation therapy (PMRT) in DCIS, identify risk factors for recurrence and select suitable candidates for PMRT.

METHODS

A questionnaire concerning DCIS management, focusing on PMRT, was distributed online via SurveyMonkey.

RESULTS

142 responses were received from 15 countries. The majority worked in academic institutions, had 5-20 years work-experience and irradiated <5 DCIS patients/year. PMRT was more given if: surgical margins <1 mm, high-grade, multicentricity, young age, tumour size >5 cm, skin- or nipple- sparing mastectomy. Moderate hypofractionation was the most common schedule, except after immediate breast reconstruction (57% conventional fractionation).

CONCLUSIONS

The present survey highlighted risk factors for PMRT administration, which should be further evaluated.