Betere prognose en gunstiger tumorstadium bij patiënten met invasief mammacarcinoom na de introductie van het bevolkingsonderzoek op borstkanker in Tilburg

To analyse the effect of the introduction of mass mammographic screening on the stage, treatment and survival of women with invasive mammary carcinoma in Tilburg, the Netherlands .

Design

Descriptive.

Methods

In the city of Tilburg and its surroundings, a population-based mammographic screening programme was introduced in 1992 and fully implemented in 1996. Based in the St. Elisabeth Hospital, the authors studied the effect of the screening programme on disease stage, treatment and survival in women treated for breast cancer in the periods 1985-1991 and 1992-1999.

Results

Between January 1, 1985 and December 31, 1999 inclusive, 1400 patients were diagnosed with invasive mammary carcinoma. In patients 50-70 years of age the proportion of TNM stage I breast cancer increased from 24 in 1985-1991 to 45 in 1992-1999 (p < 0.001). In the same age group, the overall survival rate in the period 1992-1999 was significantly higher than in the period 1985-1991 (p = 0.0009), even after adjustments for tumour stage and age (p = 0.055). The proportion of patients 50-70 years of age undergoing breast-sparing surgery decreased from 34 in 1985-1991 to 29 in 1992-1999 (p = 0.28). Of the 168 invasive cancers diagnosed in the period 1997-1999, 68 (40) were detected by the screening programme, 47 (28) between two successive rounds of screening (interval cancers) and 53 (32) in non-participants or women who had skipped one or more screening rounds. The tumours that were detected by screening had a much better prognosis than the tumours in the other two groups (p = 0.0018 and p < 0.0001, respectively).

Conclusions

A better prognosis and a more favourable tumour stage were found in patients 50-70 years of age after the introduction of the breast cancer screening programme. In spite of the full implementation of the screening programme, the majority of the invasive cancers were still detected between screening rounds or in patients who did not participate in the programme.