Pediatric breast malignancies are a thankfully rare occurrence, but this also means that literature is limited on this topic, says the present US-wide study. Here, the authors compared pediatric and adult breast malignancy. They found differences and similarities: Pediatric breast malignancies are more advanced at presentation, but overall survival is similar in adult and pediatric patients with invasive carcinoma.
The retrospective cohort study included close to 2 million cases from the US-American National Cancer Data Base. The authors compared patients ≤ 21 years to those > 21 years at diagnosis and estimated differences in demographic, tumor, and treatment characteristics.
The incidence of invasive breast malignancies in patients ≤ 21 year was 0.02 %. 99 % of adult patients had invasive carcinoma, compared with 64.8 % of pediatric patients; the remaining patients had sarcoma, malignant phyllodes, or malignancy not otherwise specified. Further results:
- Pediatric patients were twice as likely to have an undifferentiated malignancy (relative risk [RR] 2.19).
- 50 % of adults versus 22.7 % of pediatric patients presented with Stage I disease (p < 0.001).
- Pediatric patients were 40 % more likely to have positive axillary nodes (RR 1.42).
- Among patients with invasive carcinoma, pediatric patients were more than four times as likely to receive a bilateral than a unilateral mastectomy compared with adults (RR 4.56).
- Overall survival was similar.
Pediatric breast malignancies are more advanced at presentation, but overall survival is similar in adult and pediatric patients.