Changes in management techniques and patterns of disease recurrence over time in patients with breast carcinoma treated with breast-conserving therapy at a single institution

Abstract

Background: The authors reviewed changes in the initial clinical presentation, management techniques, and patterns of disease recurrence over time (1981-1996) in patients with breast carcinoma treated with breast-conserving therapy (BCT) at a single institution. The goals of the current study were to determine the frequency and use of optimal local and systemic therapy techniques and to evaluate the impact of these changes on treatment efficacy.

Methods: Six hundred seven patients with American Joint Committee on Cancer Stage I or II invasive breast carcinomas treated with BCT at William Beaumont Hospital (Royal Oak, MI) constituted the study population. All patients received at least an excisional biopsy of the primary tumor, an axillary lymph node staging procedure, and postoperative radiotherapy (RT) (a median tumor bed dose of 61 Gray [Gy] was administered). All sides were reviewed by one pathologist. Numerous clinicopathologic and treatment-related factors were analyzed to monitor changes that occurred over time. Changes in patterns of disease recurrence and treatment efficacy over time also were analyzed.

Results: Over the time period analyzed, changes at initial presentation included an increase in the mean age at diagnosis (age 56.1 years vs. 61.4 years; P < 0.001), a decrease in the number of patients with clinically palpable tumors (78% vs. 36%; P < 0.001), a decrease in the mean tumor size (2.2 cm vs. 1.6 cm; P < 0.001), but no change in the percentage of patients with negative lymph nodes (79% vs. 78%; P = 0.83). No differences over time were observed in mean tumor grade (2.0 vs. 1.9; P = 0.2) or the presence of angiolymphatic invasion (27% vs. 26%; P = 0.25). Changes in surgical management and pathologic assessment included the more frequent use of reexcision (46% vs. 81%; P < 0.001), larger mean total volumes of breast tissue specimens excised (115 cm3 vs. 189 cm3; P = 0.001), a larger percentage of patients with final negative surgical margins (74% vs. 97%; P < 0.001), and a small increase in the mean number of lymph nodes excised (13.8 lymph nodes vs. 14.1 lymph nodes; P = 0.01). The only other significant change in the pathologic management of patients over time included a doubling in the mean number of slides examined (10.6 slides vs. 21.1 slides; P < 0.001). Changes in adjuvant local and systemic therapy included an increase in the percentage of patients treated with > 60 Gy to the tumor bed (66% vs. 95%; P < 0.001), a doubling in the mean number of days from the last surgery to the start of RT (24 days vs. 50 days; P < 0.001), and a decrease in the use of regional lymph node RT (24% vs. 8%; P < 0.001). The use of adjuvant tamoxifen increased from 10% to 61% (P < 0.001). Finally, improvements were observed in the 5-year and 12-year actuarial rates of local disease recurrence (8% vs. 1% and 21% vs. 9%, respectively; P = 0.001) and distant metastases (12% vs. 4% and 22% vs. 9%, respectively; P = 0.006). No changes in the mean number of years to ipsilateral (6.5 years vs. 6.4 years; P = 0.59) or distant disease recurrence (4.6 years vs. 3.8 years; P = 0.73) were observed.

Conclusions: The impact of screening mammography and substantial changes in surgical, pathologic, RT, and systemic therapy recommendations were observed over time in the study population. These changes were associated with improvements in 5-year and 12-year local and distant control rates and suggested that improvements in outcome can be realized through adherence to best practice guidelines and continuous monitoring of treatment outcome data.