[Clinical characteristics and survival in the operable breast cancer patients with different molecular subtypes]

According to the immunohistochemical (IHC) test of ER, PR and HER-2, breast cancer can be divided into 4 different molecular subtypes: Luminal A subtype (ER or PR positive and HER-2 negative), Luminal B subtype (ER or PR positive and HER-2 positive), HER-2 subtype (ER and PR negative, HER-2 positive) and Basal-like subtype (ER, PR and HER-2 negative). This study was to analyze the clinical features of different breast cancer subtypes, and try to find the evidence of combined and individualized treatment for patients with breast cancer.

The data of 408 surgically treated breast cancer patients in the Cancer Hospital of Chinese Academy of Medical Sciences from January 1, 2002 to December 31, 2002 were collected and retrospectively analyzed. The clinicopathological features and recurrence, metastasis as well as survival of these four subtypes were compared.

Of the 408 cases, Luminal A subtype accounted for 60.8% (248/408), Luminal B subtype 7.8% (32/408), HER-2 subtype 12.5% (51/408), and Basal-like subtype 18.9% (77/408). Basal-like subtype had less lymph node metastases than other subtypes (P<0.05). HER-2 subtypes consisted of less patients aged 45 years or younger than other subtypes (P<0.05). Luminal B subtype contained less advanced cases than other subtypes (P<0.01). By August 2008, the median time of follow-up was 64 months (range, 3-79 months). Fifty-eight cases presented local recurrence or metastasis, and 51 of them died of the disease. The 5-year overall survival rates (OS) for patients with Luminal A, Luminal B, Basal-like and HER-2 subtype were 89.83%, 86.15%, 79.85% and 86.70% , respectively. The 5-year disease-free survival (DFS) rates of the four subtypes were 83.52%, 68.88%, 71.66% and 75.83%, respectively. The rate of local recurrence or metastasis in Luminal A subtype was significantly lower than that in Luminal B and Basal-like subtypes (P<0.05). The DFS time in Luminal B subtype was shorter than that in Luminal A subtype (P=0.0481). The OS and DFS time in Basal-like subtype were all shorter than that in Luminal A subtype (P=0.0077 and P=0.0306, respectively).

The distribution of each subtype in Chinese breast cancer patients is similar to that in European and American breast cancer patients. Luminal A is the most common subtype in Chinese breast cancer patients, and has a good prognosis. While Basal-like and Luminal B subtype have a poor prognosis.