Small breast cancers : Diagnosis, prognostic factors and clinical outcome in a screening population

University dissertation from Linköping : Linköpings universitet

Abstract: Breast cancer ≤ 10 mm together with ductal in situ cancer of the breast (DCIS) today constitute more than 40% of screening detected breast malignancies. Prognostic factors, diagnosis and clinical outcome for invasive breast cancers ≤ 10 mm and local recurrence in DCIS were evaluated.Histopathological grading was done in 248 ductal breast cancers and grade III was correlated to aneuploidy, increased S-phase fraction and receptor negative tumours. Life table analysis showed a significant increase in breast cancer mortality in grade III tumours (p < 0.001).Hormone receptors and cytometric variables were studied in ≤ 10 mm breast cancers. Around 60% of these small cancers were evaluable. Aneuploidy was found in 52% and SPF ≥ 10 in 20%. Mean SPF was 4.8 in diploid and 7.6 in aneuploid tumours. A potentially high risk group with high SPF figures and receptor negative tumours comprise 7% of the patients.Diagnostic surgery was performed in 314 non-palpable breast lesions. Insufficient excisions were observed in 16 cases (5%), mostly in lesions with microcalcifications and in situ cancers ≥ 30 mm in extent. Underestimation of in situ cancers is the main reason for inadequate surgery.DCIS comprises approx 10% of breast malignancies. In 38 cases operated with breast preserving surgery 13% got local recurrence in median 60 months follow-up.Recurrence free survival in patients with ≤ 10 mm breast cancers were evaluated for 324 cases. Only 8% of these patients had adjuvant treatment. Lymph node involvement was found in 9% of screening detected and 20% in clinically detected cancers (p < 0.03). Median prospective follow-up time was 7 years and distant metastases appeared in 8 patients, local recurrence in 3. Life table analysis showed 97% overall distant recurrence free survival, 99% in node negative and 79% in node positive patients (p < 0.001).We can today, by grading and cytometric variables, find subgroups with high risk of recurrence after breast cancer surgery in small breast cancers. These are probably the only patients that benefit from adjuvant treatment and need follow-up outside mammography screening. Breast conserving surgery can be performed in the majority of DCIS patients.

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