Comparison of pathological characteristics between self-detected and screen-detected invasive breast cancers in Chinese women: a retrospective study

Abstract

Background: In China, there is insufficient evidence to support that screening programs can detect breast cancer earlier and improve outcomes compared with patient self-reporting. Therefore, we compared the pathological characteristics at diagnosis between self-detected and screen-detected cases of invasive breast cancer at our institution and determined whether these characteristics were different after the program's introduction (vs. prior to).

Methods: Three databases were selected (breast cancer diagnosed in 1995-2000, 2010, and 2015), which provided a total of 3,014 female patients with invasive breast cancer. The cases were divided into self-detected and screen-detected groups. The pathological characteristics were compared between the two groups and multiple imputation and complete randomized imputation were used to deal with missing data.

Results: Compared with patient self-reporting, screening was associated with the following factors: a higher percentage of stage T1 tumors (75.0% vs 17.1%, P = 0.109 in 1995-2000; 66.7% vs 40.4%, P < 0.001 in 2010; 67.8% vs 35.7%, P < 0.001 in 2015); a higher percentage of tumors with stage N0 lymph node status (67.3% vs. 48.4%, P = 0.007 in 2010); and a higher percentage of histologic grade I tumors (22.9% vs 13.9%, P = 0.017 in 2010).

Conclusion: Screen-detected breast cancer was associated with a greater number of favorable pathological characteristics. However, although screening had a beneficial role in early detection in China, we found fewer patients were detected by screening in this study compared with those in Western and Asian developed countries.

Keywords: Breast cancer; Chinese; Pathological characteristics; Screen-detected; Self-detected.

Figure 1. Comparison of the difference between self-detected and screen-detected breast cancer patients in (A) T stage, (B) N stage, and (C) histologic grade in 1995–2000, 2010, and 2015.

Techniques of dealing with missing data included (R) complete-case analysis; (A1–5) multiple imputation by chained equations; (B1–5) completely randomized imputation; (C) arbitrarily replacing missing mode of detection into self-detected mode and deleting other missing values in the group; (D) arbitrarily replacing all missing detection method values into screen-detected mode and deleting other missing values in the group.

Figure 2. Frequency distribution at diagnosis, by detection mode in 1995–2000, 2010, and 2015.

The age distribution of screen- and self-detected patients was constructed using the 2016 Excel software, while the patients with missing values of detection mode were deleted. Periods of self-detected patients included 1995–2000 in full line (Sel.1995–2000), 2010 in dotted dot line (Sel.2010), and 2015 in square dot line (Sel.2015). Periods of screen-detected patients included 1995–2000 in dash-dot line (Scr.1995–2000), 2010 in long dashed line (Scr.2010), and 2015 in short dashed line (Scr.2015).