The Clinical Characteristics and Prognosis of Chinese Early Stage Breast Cancer Patients: A Retrospective Study

To the Editor: Despite the lower incidence of breast cancer in China, the absolute number of new cases is high because of large population (there are 1.31 billion inhabitants). Of the new cases of breast cancer in the world, 21.3% are diagnosed in China. In addition, cancer registries in China do record annual increases in incidence of 3–4%, which is higher than in other countries (1). There is no nationwide breast screening program in China because of relatively lower breast cancer incidence and resource constraint. In contrast to Western countries, breast conservation therapy is uncommon and most of the patients receive mastectomy along with more widespread use of adjuvant therapy. Given these differences, we evaluated the clinical characteristics and prognosis of breast cancer in China. A random selection was made of 1,197 records out of 5,987 patients diagnosed with breast cancer. For 1,086 patients, baseline information was available (see Table 1); for 830 patients 5-year follow-up information was available (see Table 2). The median age at diagnosis of patients was 48.0 years (range: 19–80 years), and 431 (39.7%) women were older than 50. In contrast, the median age of diagnosis of breast cancer is higher in European Countries and the United States (median: 58–63) (2,3). These differences cannot be explained by differences in life-expectancy, as there are only small differences in life-expectancy between China (about 75), Korea (about 82), and Western Countries (about 79–83) (4). These differences can also not be explained by the absence of a nation wide screening program, as in Western countries without screening program the median age at diagnosis of breast cancer is about 60 (3). In a multi-ethnic cohort study, the breast cancer risk of Asian postmenopausal women appeared to be comparable to American women after adjusting for the risk factors, such as overweight and alcohol consumption (5). It seems reasonable to hypothesize that environmental factors play a role. The patients in our study had more advanced stages of breast cancer than those in the United States and European studies. The pathologic stage was T1 and T2 in 814 (75.0%) patients; 475 patients (43.7%) were in pathologic stage N0. The possible explanation might be the absence of a nationwide breast cancer screening program in China, whereas such programs are fully or partly implemented in majority of developed countries (6). A minority of women (n = 44, 4.1%) received breast conserving treatment and all of these patients with specified stage information 31 (70.5%) were in stage I and stage II. Besides 95 (48.0%) stage III patients, 23 (22.5%) stage I and 264 (38.4%) stage II patients received neo-adjuvant chemotherapy. A majority of women received post-treatment adjuvant therapy, with 588 (54.1%) receiving radiation therapy, 896 (82.5%) receiving adjuvant chemotherapy, and 374 (34.4%) receiving endocrine therapy; 497 out of 1041 patients (47.7%) received mastectomy combined with radiation therapy and chemotherapy. Of the 475 patients with N0 stage, 230 (48.4%) patients received radiation therapy, and 382 (80.4%) patients received adjuvant chemotherapy. Of the 102 patients with stage I tumors, 81 (79.4%) patients received mastectomy, and 36 (44.4%) patients received mastectomy as well as radiotherapy. In 683 patients with stage II tumors, 580 patients received mastectomy, and 354 (61.0%) patients received mastectomy as well as radiotherapy. Breast conservation therapy was uncommon in China until the late 1990s even in those areas with more westernized culture because of the relatively small breast size of Chinese women and uncertainty about the long-term clinical and cosmetic outcome in this ethic group. Mastectomy was still widely perceived as the only curative treatment for Chinese women (7). Furthermore, the adjuvant therapies were accepted widely. The more aggressive treatment strategies are carried out after taking into account the patients' preferences, financial status, and knowledge. Despite the unfavorable primary tumor status, the patients in our study showed a good disease-free survival and overall survival, being 84% and 88% at 5 years, and 77% and 83% at 10 years, respectively. This was comparable to survival data from the United States and Europe (2,3). The end point evaluated was death from any cause in this study, so the competing risk should be taken into consideration because the patients in western countries are at higher risk of dying from other causes than older age. The incidence of relapse was smaller as compared with some other studies (4% versus 4–9%) (8–10). Five-year cumulative incidences of loco-regional recurrence and contra-lateral recurrence were 2.9% (95% CI: 1.9–3.9) and 0.7% (95% CI: 0.2–1.2), respectively. The combination of mastectomy with systemic adjuvant radiotherapy and chemotherapy in our hospital was a reasonable explanation for the lower incidence of loco-regional recurrence. There might be some other genetic and environmental factors needed to be clarified. In summary, breast cancer patients in our series had more advanced tumor stages and were given more aggressive treatment. Despite this, the clinical outcome was comparable to Western countries and less relapse was found. Our findings indicate that more aggressive treatment is acceptable in those areas without routine breast screening program.