NEW YORKIn patients with ductal carcinoma in situ (DCIS), the identification of positive sentinel lymph nodes (SLNs) is unlikely to be clinically significant, David Brenin, MD, of Columbia-Presbyterian Medical Center, said at the San Antonio Breast Cancer Symposium.
Several recent studies of SLN biopsy in DCIS patients have shown positive results in 6% to 14% of patients. Dr. Brenin pointed out that these rates are higher than the 1% to 2% prevalence seen with axillary node dissection and have raised the question of whether axillary metas-tases identified by SLN biopsy are clinically significant in DCIS patients.
If positive sentinel lymph nodes were clinically significant for DCIS patients, then one would expect some proportion of DCIS patients to develop distant metastases without first or simultaneously developing an invasive locoregional recurrence or invasive second breast cancer, Dr. Brenin said.
The study involved 432 DCIS patients treated between 1980 and 1998 at Columbia-Presbyterian. None had any type of axillary staging, and no patient had microinvasion.
At a median follow-up of 3 years, only two patients had died of metastatic breast cancer or developed a distant metastasis that was not preceded by or accompanied by an invasive local recurrence or invasive second primary breast cancer. The actuarial disease-specific survival was 98.2%, which was unchanged if the analysis was restricted to patients with 5-year follow-up and was little changed, at 97.3%, in patients followed for 7 years.
The findings were virtually identical to those of a second study by Dr. Brenin and his colleagues, showing 97.6% 10-year disease-specific survival in 326 DCIS patients who underwent surgery and axillary dissection .
Our results and others show that breast cancer survival for DCIS patients treated without axillary staging of any kind is excellent, Dr. Brenin said. Therefore, metastatic disease identified through SLN techniques in DCIS patients is unlikely to be clinically significant.
In response to a question, Dr. Brenin agreed that axillary staging is appropriate and useful for selected DCIS patients, eg, those with large palpable tumors.