What happened, in summary

This 67-year-old African American woman, a nonsmoker, had 2 cancers found incidentally on imaging: a 2 cm right breast mass in the axillary tail and a 1 cm mass in the upper lobe of the right lung. Biopsy of the breast mass showed a poorly differentiated adenocarcinoma consistent with primary breast cancer. Imaging raised the possibility that the lung lesion could be metastatic breast cancer, but its appearance was more consistent with a synchronous primary lung cancer. She underwent right lumpectomy with sentinel lymph node biopsy and right upper lobectomy with thoracic lymphadenectomy, both with curative intent. Pathology confirmed 2 separate primary cancers. The breast tumor was a 1.5 cm grade II infiltrating mammary carcinoma with ductal and lobular features. It was estrogen receptor-positive, progesterone receptor-positive, and HER2-negative, and the sentinel lymph node was negative, giving Stage IA breast cancer. The lung tumor was a 1.3 cm mixed-histology adenocarcinoma diagnosed as non-small-cell lung cancer. It invaded the visceral pleura and had 2 positive lymph nodes, giving Stage IIA lung cancer. Molecular testing of the lung tumor showed KRAS wild-type, EGFR wild-type, and no ALK gene rearrangement by FISH. These findings supported treating the lung cancer as a separate early-stage but node-positive primary, not as breast cancer spread. She received 4 cycles of adjuvant pemetrexed/cisplatin for lung cancer, then breast radiation and an aromatase inhibitor planned for 5 years to reduce breast cancer recurrence risk. As of April 2014, more than 2 years of follow-up showed no recurrent disease in either cancer site.