Medial tumor localization in breast cancer--an unappreciated risk factor?

PURPOSE

To demonstrate the unfavorable results in survival rates in patients with medial breast cancer compared to patients with laterally located tumors of the mammary gland.

PATIENTS AND METHODS

Between 1984 and 1995, 1,089 patients presenting with a total of 1,100 pT1-2 invasive carcinomas of the breast were treated at the authors' institution. 707 presented with tumors in the lateral quadrants, 294 with tumors in the medial quadrants, and 99 with tumors in the central quadrant. Treatment protocols involved breast-conserving surgery and whole-breast radiotherapy in all women, followed by a tumor bed boost dose according to risk factors for local recurrence. All axillary node-positive patients underwent systemic therapy (six cycles of classic CMF and/or 2-5 years of tamoxifen 20 mg/day). Rates of actuarial survival and local control were calculated by the Kaplan-Meier method and differences in survival curves were compared by use of the log-rank test.

RESULTS

The mean follow-up of survivors was 97 months (range 36-192 months). Comparing patients with medial and lateral tumors, the actuarial survival data were significantly better for patients with lateral tumors. At 10 years, overall survival for patients with medial tumors was 71%, for patients with lateral tumors 81.8% (p < 0.025), disease-specific survival for patients with medial tumors 79.9%, for patients with lateral tumors 89.1% (p < 0.025). There was no significant difference in local tumor control according to tumor location.

CONCLUSION

Medial tumor location is associated with a lower survival rate, but not with inferior local tumor control. Failure to identify nodal metastases confined to the internal mammary chain may lead to undertreatment with systemic/local agents and compromised survival.