Background: In Finland, organized national mammography screening program has shown a decrease in mortality from breast cancer since its introduction in late 1980s. The incidence and mortality rate is rapidly rising in countries where regular screening program is not available. However, it is still not clear how much the presence of symptoms in screening exams increases the risk of breast cancer. We proposed a study to assess the association of earlier symptoms findings with the occurrence of breast cancer.
Method: A cross-sectional study was performed among women aged between 50 and 69 years who had breast cancer screening during the period 2006-2010. A total of 1.2 million mammography screening was performed and symptoms (lump, retraction, scar, secretion and mole) were reported by women and radiographer at the time of screening visit. Six thousand, four hundred and forty-five women were diagnosed with breast cancer. Breast cancer risk was calculated for each symptom using the odds ratios (OR) at 95% confidence intervals (CI) with or without interaction effect in logistic regression model. Moreover, tumor characteristics were linked with self-reported as well as radiographer reported symptoms.
Results: Women reporting of lump had an increased odds of breast cancer in both self-reported (OR = 7.23, 95% CI = 6.45 to 8.11) as well as in radiographer findings (OR = 6.74, 95% CI = 6.12 to 7.41). Similarly, retraction had 3-fold increased risk of breast cancer in self-reported and 2.14-fold increase in radiographer reported findings. Other symptoms showed little increase in odds of breast cancer. The three-way interaction of symptoms (lump, retraction and scar) and the breast cancer risk was found higher in both self-reported (OR = 12.25, 95% CI = 2.93 to 51.12) as well as in radiographer reported (OR = 11.4, 95% CI = 4.63 to 28.09) symptoms. A lower sensitivity and higher specificity was found in self-reported and in radiographer reported symptoms.
Conclusion: Our findings reinforce the importance of fully evaluating the symptoms as a predictor of breast cancer. This study may be relevant for a large number of countries (without mammography screening program) to develop clinical breast examination as an alternative option in population-based breast cancer control, however, the impact may vary with study settings and availability of screening and diagnostic services
