Breast cancer in young women: Pathologic features and molecular phenotype

Controversy exists about the prognosis of breast cancer in young women. Our objective was to describe clinicopathological and prognostic features to improve adjuvant treatment indications.

We conducted a retrospective multi centre study including fifteen French hospitals. Disease-free survival's data, clinical and pathological criteria were collected.

5815 patients were included, 15.6% of them where between 35 and 40 years old and 8.7% below 35. In 94% of the cases, a palpable masse was found in patients ≤35 years old. Triple negative and HER2 tumors were predominantly found in patients ≤35 (22.2% and 22.1%, p < 0.01). A young age ≤40 years (p < 0.001; hazard ratio [HR]: 2.05; 95% confidence limit [CL]: 1.60-2.63) or ≤35 years (p < 0.001; [HR]: 3.86; 95% [CL]: 2.69-5.53) impacted on the indication of chemotherapy. Age ≤35 (p < 0.001; [HR]: 2.01; 95% [CL]: 1.36-2.95) was a significantly negative factor on disease-free survival. Chemotherapy (p < 0.006; [HR]: 0.6; 95% [CL]: 0.40-0.86) and positive hormone receptor status (p < 0.001; [HR]: 0.6; 95% [CL]: 0.54-0.79) appeared to be protector factors. Patients under 36, had a significantly higher rate of local recurrence and distant metastasis compared to patients >35-40 (21.5 vs. 15.4% and 21.8 vs. 12.6%, p < 0.01).

Young women present a different distribution of molecular phenotypes with more luminal B and triple negative tumors with a higher grade and more lymph node involvement. A young age, must be taken as a pejorative prognostic factor and must play a part in indication of adjuvant therapy.