Adenocarcinomas account for most cases of cancer of unknown primary (CUP). Women with adenocarcinoma in the lymph nodes under the arm (axillary lymph nodes) may be treated as if they have a breast cancer. Most cancers in women that spread to these lymph nodes are breast cancers. Treatment of women with adenocarcinoma found only in the axillary lymph nodes is similar to treating women with stage II or stage III breast cancer.
Surgery is often among the main treatments for women with adenocarcinoma in the axillary lymph nodes. Surgery is done to remove the axillary lymph nodes (axillary lymph node dissection). Surgery may also include removing the breast (mastectomy) on the same side as the lymph nodes that contain cancer.
Radiation therapy to the breast may be done instead of a mastectomy.
Chemotherapy or hormonal therapy or both may be given in addition to surgery or radiation therapy (adjuvant therapy). The type of therapy given will depend on the woman's age and whether the cancer cells are hormone-receptor positive.
Women with HER2-positive tumours may also be offered treatment with trastuzumab (Herceptin), a monoclonal antibody used to treat breast cancer tumours that make large amounts of the HER2 (ERBB2) protein.
Women with CUP may be offered the opportunity to participate in clinical trials. For more information, go to clinical trials.
The Canadian Cancer Society is funding lifesaving clinical trials that give people with cancer access to the newest types of treatment.