Invasive Local Recurrence in DCIS Can Turn ‘Indolent’ Disease Into Life-Threatening Condition

REIMS, France—Results of a French study suggest that oncologists should not underestimate the potential threat posed by local recurrence of ductal carcinoma in situ (DCIS). Reporting on the DCIS experience of 11 French cancer centers, Bruno Cutuli, MD, a radiation oncologist at the Center for Radiotherapy and Oncology at Polyclinique Courlancy in Reims, France, emphasized the importance of optimal initial treatment, close follow-up and definitive treatment after an invasive local recurrence.

The study population was 1,521 patients treated for pure DCIS between 1985 and 1996, Dr. Cutuli said. The median age of the group was 53. Initial DCIS treatment was mastectomy (306 patients), conservative surgery alone (403 patients), and conservative surgery plus radiotherapy (812 patients).

The median follow-up for the group was 83 months. The median follow-up after local recurrence was 44 months.

Recurrence Rate by Treatment

A total of 213 patients experienced a local recurrence. Of these, 90 had in situ lesions, and 123 had invasive tumors. The local recurrence rate was 1.6% after mastectomy (5 of 306 patients), 26.1% after conservative surgery alone (105 of 403 patients), and 12.6% after conservative surgery plus radiotherapy (103 of 812 patients).

Among patients treated with mastectomy, the median time to local recurrence was 55 months. All five recurrences were invasive cancers. One patient had a nodal recurrence, and two patients had metastases and subsequently died.

In the conservative surgery-alone group, the median time to recurrence was 37 months, and 82% of the recurrences occurred in less than 5 years. The types of recurrence were: in situ (52 patients), invasive (53 patients), nodal (9 patients), and distant metastasis (5 patients).

For patients treated with conservative surgery plus radiotherapy, the median time to recurrence was 53 months, and 67% of the recurrences occurred in less than 5 years. The types of recurrence were: in situ (38 patients), invasive (65 patients), nodal (14 patients), and metastasis (11 patients).

When the researchers restricted their analysis to patients who experienced an invasive recurrence, the metastasis rate was 40% among those treated with mastectomy (2 of 5 patients), 9.4% among those treated with conservative surgery alone (5 of 53 patients), and 16.9% for those treated with conservative surgery plus radiotherapy (11 of 65 patients). In contrast, the metastasis rate among women who developed an in situ recurrence was 1.1% (1 of 90 patients).

Dr. Cutuli underscored the importance of close follow-up of patients treated for DCIS, especially among high-risk patients-those younger than age 40 and those who have comedocarcinoma or large tumors. In the study, 78% of in situ and microinvasive (less than 2 mm) local recurrences were detectable only by mammography.

Initial Therapy Is Crucial

About 60% of the patients underwent salvage mastectomy after their local recurrence. Other patients were treated with conservative surgery, followed in the majority of patients by radiotherapy. The researchers noted a 20% to 25% rate of secondary local recurrence in patients treated conservatively. The metastasis rate after treatment for an in situ local recurrence was 2.2% compared to 12.6% for patients with an invasive recurrence.

"Mastectomy remains the safest treatment for local recurrence," Dr. Cutuli said. "Only in very selected cases should a second conservative treatment be proposed. Axillary dissection should be performed in cases of invasive local recurrence and for large, high-grade DCIS local recurrence." He added that "systemic therapy and nodal irradiation should be considered for patients with invasive local recurrence and nodal involvement."

"DCIS is not completely an indolent disease," he concluded, "and we must remember that the initial optimal treatment is a crucial step to curing our patients."