Dilemma in multifocal breast cancer – largest versus aggregate diameter

Area of Science:

• Oncology
• Breast Cancer Research
• Surgical Pathology

Background:

• Existing research indicates multifocal breast cancer (MBC) presents a higher risk of lymph node metastases than unifocal breast cancer (UBC).
• This distinction significantly impacts patient prognosis and therapeutic strategies.
• The study aimed to validate these findings within the institution's patient cohort.

Purpose of the Study:

• To investigate the association between multifocal breast cancer and lymph node metastasis.
• To compare the rates of lymph node involvement in multifocal versus unifocal breast cancer cases.
• To determine if multifocal breast cancer indicates a heavier disease burden.

Main Methods:

• A retrospective analysis of 75 patients diagnosed with multifocal breast cancer between 2000 and 2007.
• Inclusion of data on tumor size (largest, aggregate, extent diameter) and patient outcomes (lymph node metastases, recurrence, mortality).
• Comparison with 77 age-matched control subjects with unifocal breast cancer from the same period.

Main Results:

• The multifocal group (average age 58) showed a 52% rate of positive lymph nodes, versus 36% in the unifocal group (average age 57).
• Tumor characteristics differed, with multifocal cancers including a higher proportion of lobular and mixed types compared to the predominantly ductal unifocal cancers.
• Average largest tumor diameter was 22.1 mm for multifocal and 18.4 mm for unifocal breast cancer.

Conclusions:

• Multifocal breast cancer is significantly associated with an increased incidence of lymph node metastases.
• This higher metastatic rate suggests multifocal disease may represent a more aggressive cancer phenotype.
• Findings support considering multifocal breast cancer for more intensive treatment approaches.