Extracapsular axillary node extension in patients receiving adjuvant systemic therapy: an indication for radiotherapy?

PURPOSE

This is a retrospective review into the patterns of failure of 82 patients with Stage II or III breast cancer who had extracapsular extension (ECE) of axillary nodal metastases and who received systemic chemotherapy or hormonal therapy without loco-regional radiation.

METHODS AND MATERIALS

The clinical records of patients with axillary node positive (T1-T3, N1, 2) Stage II or III breast cancer seen at the London Regional Cancer Centre between 1980-1989 were reviewed. Patients were identified who underwent segmental mastectomy with axillary node dissection or modified radical mastectomy and received adjuvant chemotherapy or tamoxifen but did not undergo loco-regional radiation. Eighty-two patients within this group had pathologic evidence of extracapsular axillary node extension (ECE). For 45 of these patients the extension was extensive, and for the remaining 37 it was microscopic. This ECE-positive group was compared to a subgroup of 172 patients who did not have pathologic evidence of extracapsular axillary node extension but had metastatic carcinoma confined within the nodal capsule.

RESULTS

Median age of the 82 ECE-positive patients was 56 years. Twenty-five patients had had a segmental mastectomy, the remainder a modified radical mastectomy. Median actuarial survival was 60 months, with a median disease-free and loco-regional failure-free survival of 38 months. Seventy-eight percent of these patients developed a recurrence, which was loco-regional in 60% (21% local, 21% regional, 2% local and regional, and 16% loco-regional and metastatic). There was a 36% recurrence rate in intact breast, 14% the chest wall following modified radical mastectomy, 7% relapsed in the axilla, 12% in supraclavicular nodes, and 1% in the internal mammary nodes. A comparison of the 82 ECE-positive patients with a group of 172 ECE-negative patients determined that there was a statistically significant difference between the two groups in terms of survival (overall and disease-free) and loco-regional recurrence. Univariate analysis of the entire 254 node-positive patient group revealed extracapsular nodal extension (ECE) to be a prognostically significant factor for actuarial and disease-free survival as well as for loco-regional failure, but ECE did not remain an independently prognostic factor after multivariate analysis. Segmental mastectomy, positive resection margins, and ER negative status increased the risk of loco-regional recurrence within the ECE-positive group.

CONCLUSIONS

Extracapsular axillary node extension is a prognostically significant factor for actuarial survival, disease-free survival, and loco-regional failure but not independent of other adverse prognostic factors. It is a marker for increased loco-regional recurrence associated with doubling of breast, chest wall, and supraclavicular recurrence rates. The risk of axillary relapse in patients who have had an adequate level I and II axillary dissection but demonstrate extracapsular extension is low (7%). We recommend breast/chest wall and supraclavicular radiation for all patients with pathologic evidence of such extranodal extension who have had a level I and II axillary dissection regardless of the number of positive axillary nodes. Axillary irradiation should be considered for patients who have had only an axillary sampling or level I axillary dissection.