A 45-Year-Old Woman Is Evaluated Because of a Palpable 2-Cm

A 45-year-old woman is evaluated because of a palpable 2-cm right axillary lymph node. The lymph node is completely resected, and histologic study shows adenocarcinoma; hormone receptors are negative. Bilateral mammography is negative, as is MRI of the right breast. CT scans of the chest and abdomen are negative for tumor, and no further lymphadenopathy is detected. Results of bone scan and MRI of the head are also unremarkable. The patient had been previously healthy and has never smoked. Which of the following statements about this patients condition is correct?

A) Breast cancer is the most likely diagnosis, and optimal therapy for breast cancer paradigm should be initiated.
B) Lung cancer is the most likely diagnosis, and optimal therapy for lung cancer paradigm should be initiated.
C) All known disease has been resected, and the patient requires careful monitoring for possible future recurrence.
D) Radiation therapy to the right axilla is required with fields encompassing the right breast.