Treatment

Dr. Marshall: What are the treatment options for patients diagnosed with intracystic papillary carcinoma of the breast?

Dr. Finlayson: It depends on the histologic findings. If it is a case of pure IPC, complete local resection or central duct excision without axillary dissection is the treatment of choice.[18] However, this will change depending on whether DCIS exists outside the main tumor mass or an invasive component is present. Most early researchers failed to distinguish between these different patient groups, and the overall impression was that IPC had an unfavorable prognosis and should be treated with radical mastectomy. In a recent review of 40 patients with IPC, some of whom presented with DCIS and some of whom presented with invasion, the incidence of recurrence of IPC did not differ between these three groups, regardless of the type of surgery (local excision or mastectomy with or without lymph node dissection) and whether radiation was administered.[11] This could be interpreted as evidence for the support of conservative surgical therapy.

This patient's IPC was estrogen receptor-positive in 100% of cells, progesterone receptor-positive in 15% of cells, and HER2/neu-negative by immunohistochemistry (HercepTest). Most IPCs are estrogen receptor- and progesterone receptor-positive, and therefore, drugs such as tamoxifen have a theoretical benefit as adjuvant therapy. The role of such adjuvant radiotherapy remains to be further defined. High nuclear grade of the tumor cells and the presence of necrosis do indicate tumors that are more likely to behave aggressively.[11] Adequate sampling of the initial biopsy is critical to identify these characteristics in the IPC lesion, as well as to determine the presence of invasion or separate foci of ductal carcinoma in situ.

There should always be an individual discussion with the patient regarding treatment options in light of the tumor histology and the presence of any additional lesions. In this case, the patient had additional low-grade ductal carcinoma in situ outside the main lesion, and she opted for a total mastectomy.

Dr. Marshall: What did the mastectomy specimen show?

Dr. Singh: The biopsy cavity from her prior procedure was easily seen, and the area surrounding this was firm. Histologically, there were two 2-mm foci of ADH. There was no residual carcinoma in situ. No lymph nodes were sampled.

Follow-up and Prognosis

Dr. Marshall: Do intracystic papillary carcinomas metastasize to lymph nodes, and when should a sentinel node biopsy be done?

Dr. Finlayson: Just as the additional pathology findings help determine the best surgical treatment, they also affect the decision to sample lymph nodes. In a study of 14 patients with IPC, 7 had an axillary dissection and none of those patients had lymph node involvement.[18] Another study also showed no nodal involvement in 11 IPC patients who had axillary dissections.[19] It is rare even for invasive papillary carcinoma of the breast to be associated with lymph node metastases (< 1% of cases). However, tumors with a high histologic grade and large surface area are more likely to metastasize to lymph nodes or recur locally.[5,9]

The low frequency of axillary nodal involvement in IPC does not justify axillary dissection, and sentinel node dissection is an excellent alternative. Remember, however, that patients with pure low-grade IPC and no concurrent ductal carcinoma in situ or invasion can be treated with lumpectomy alone.[11] If after adequate sampling the lesion has distinctly separate areas of ductal carcinoma in situ or evidence of invasion, then it is prudent to perform a sentinel node dissection. If that shows metastatic carcinoma, an axillary node dissection may then be performed.

Dr. Marshall: What is the prognosis for these tumors, how are they followed up, and what factors influence prognosis?

Dr. Finlayson: IPC is generally a low-grade carcinoma with an overall excellent prognosis. In one study of 77 patients, the 5- and 10-year survival rates were both 100% and the 5- and 10-year disease-free survival rates were 96% and 91%, respectively.[2] There have been reports of patients developing systemic metastases 4 or 5 years after their initial surgery, and this is similar to the tendency for "late recurrences" that is seen in patients with another good-prognosis type of breast cancer—mucinous carcinoma.

Patients with papillary carcinoma have an increased 15-year survival rate compared to patients with breast carcinoma of no special type, and there have been no reports of disease-related deaths for patients with pure IPC.[4] Moreover, no increased risk of disease in the contralateral breast has been reported for patients with IPC. If there is DCIS outside the main lesion or associated invasive carcinoma, then there is an increased risk for local recurrence and metastases, but the prognosis is still very good. A study that followed 40 patients with pure IPC, IPC with DCIS, or IPC with invasion revealed disease-free survival rates of 85% and 77% at 5 and 10 years, respectively, and a disease-specific survival rate of 100%.[11]

In the current case, the patient had IPC with low-grade DCIS in the surrounding ducts. While she has little if any risk of dying from this disease, since she is young, she does have some risk for recurrence. Consequently, she will undergo regular follow-up with breast exams and mammography of her contralateral breast.