Prognostic factors in ductal carcinoma in situ of the breast: results of a retrospective study of 575 cases. The Association for Research in Oncologic Gynecology.

Objective: Conservative treatment for ductal carcinoma in situ of the breast exposes patients to the risk of infiltrating recurrence which can lead to metastasis. The primary purposes of this retrospective study were to evaluate diagnostic and therapeutic methods over a 10-year period and to validate prognostic factors. This information should greatly improve patient selection for conservative treatment or mastectomy.

Study Design: A multi-institutional data base including 575 patients treated between 1983 and 1993 was established by combining data from 16 French institutions. Survival at 5 and 7 years was studied as a function of various prognostic factors.

Results: Recurrence-free survival at 7 years was 0.96 after modified radical mastectomy and 0.83 after breast-conserving treatment and radiotherapy (P=0.003). Metastasis-free survival at 7 years was 0.99 after modified radical mastectomy and 0.94 after breast-conserving treatment and radiotherapy (not significant). No factor was predictive of local recurrence after mastectomy. Clinical stage was the only factor significantly correlated with metastasis after mastectomy. Recurrence-free survival after breast-conserving treatment with radiotherapy was significantly lower for patients with comedo carcinoma, multifocal lesions, or unclear resection margins, regardless of whether the histological type was comedo or non-comedo carcinoma. Metastasis-free survival was significantly lower for patients with multifocal lesions and for patients with unclear margins after excision of comedo carcinoma.

Conclusions: Breast-conserving treatment with radiotherapy is a valid alternative to mastectomy. Patients must be selected carefully on the basis of morphological criteria. Swift gains in therapeutic outcome can be obtained by stressing quality control at each stage of diagnosis and treatment.