Integrated Surgical Institute LLC

Breast cancer during pregnancy is uncommon; however, it is one of the most common malignancies affecting pregnant women. Pregnancy-associated breast cancer (PABC) is a complex entity characterized by unique risk factors, presentation, and pathology. Furthermore, although management generally aims to mirror that for nonpregnant patients, there are distinct aspects of oncologic care delivery specific to PABC. The focus is on optimizing maternal outcomes while maximizing maternal and fetal safety. A multidisciplinary approach is key, and the timing of various treatment modalities is critical. Postdelivery care and counseling are also imperative to address issues such as contraception, breastfeeding, and future fertility. In the present review, we discuss the current knowledge base and the diagnostic and treatment landscape for PABC, including recent literature and practice pattern updates.

As outcomes for low-risk breast cancer continue to improve, research and clinical paradigms are increasingly focused on appropriate deintensification with the goal of improving the therapeutic ratio of breast cancer treatment. These deintensification approaches span across disciplines including breast surgery, radiation therapy, and systemic therapy. With regard to breast surgery, studies have continued to push deintensification when it comes to surgical margins with breast conservation, reducing re-excision rates, whereas deintensification of axillary surgery has reduced the rates of axillary lymph node dissection and increasingly the need for any axillary surgery, including sentinel lymph node biopsy for low-risk patients. With regard to radiation therapy, studies have allowed for a drastic reduction in treatment duration, whereas approaches that reduce the target of treatment have led to a change from from treatment daily for 5-7 weeks to many low-risk patients completing treatment in just five treatments. With regard to systemic therapy, use of genomic assays and tumor biology has led to reduced utilization of cytotoxic chemotherapy, with studies also allowing for dose reduction of endocrine therapy for patients with ductal carcinoma in situ. Moving forward, greater focus should be placed on interdisciplinary deintensification approaches such as the consideration of radiation therapy alone as compared with endocrine therapy alone for low-risk breast cancers.

Partial breast irradiation (PBI) delivered with intensity modulated radiation therapy over 5 fractions every other day represents an attractive, convenient method of delivering adjuvant radiation therapy for well-selected patients without compromising oncologic or toxicity outcomes. Condensing this regimen to a week of treatment through consecutive daily delivery may further increase patient convenience, though a comparison of toxicities between daily and every other day regimens is limited.

We retrospectively reviewed 507 patients from an institutional registry undergoing PBI for ductal carcinoma in situ (DCIS) or early-stage breast cancer (T1-2N0/x) from 2015 to 2022. All patients received 30 Gy in 5 fractions with intensity modulated radiation therapy. Acute (toxicity within 90 days of treatment) and chronic toxicity were recorded.

Of the 507 patients, 351 were treated every other day, and 159 were treated daily. Median follow-up was longer in the every-other-day group (2.4 vs 1.9 years, P < .001). With regards to acute toxicity, there was slightly reduced grade 1 to 2 dermatitis with daily treatment (39% every other day vs 35% daily, P = .06), while rates of fatigue (18% every other day vs 20% daily, P = .09) were similar. Rates of chronic toxicities were comparable between the two approaches, with no differences in the rates of chronic hyperpigmentation (14% every other day vs 14% daily, P = .97), telangiectasias (1% every other day vs 1% daily, P = .92), mild fibrosis/induration (13% every other day vs 13% daily, P = .91), and lymphedema (0% every other day vs 1% daily, P = .31).

Overall, 5-fraction PBI delivered daily appears to be well tolerated with similar acute and chronic toxicity to every other day fractionation.