Applied Radiology

Prepared by Karen Mourtzikos, MD from The Johns Hopkins Hospital, Baltimore, MD and Javier Villanueva-Meyer, MD from River Oaks Imaging, Houston, TX.

CASE SUMMARY

A 30-year-old woman was diagnosed with infiltrating ductal carcinoma in the right breast in 1996. Since she had a family history of breast cancer, she opted for bilateral mastectomy at the time of her initial diagnosis, followed by recon-struction with silicone implants. She subsequently underwent two cycles of chemotherapy and radiation therapy. She was asymptomatic for 4 years, at which time she noticed erythema and swelling of the right supraclavicular region.

A right upper chest skin punch biopsy was performed in December 2000, and the pathology results showed carcinoma with features favoring metastatic adenocarcinoma of the dermis.

DIAGNOSIS

Recurrent breast cancer in a patient with bilateral breast implants

IMAGING FINDINGS

In January 2001, 8 days after the biopsy, follow-up imaging was performed. Radiologic workup with mammography, breast ultrasound, and computed tomography (CT) of the chest, abdomen, and pelvis showed clips and surgical changes in the right axilla, with no evidence of local recurrence or lymph node involvement.

Positron emission tomography (PET) done with 10 mCi fluorodeoxyglucose (FDG) and dedicated-ring bismuth germanate (BGO) system showed abnormal increased uptake in the superior-posterior aspect of the right implant, in the right supraclavicular region, and in the left axilla (Figure 1).

The PET results helped determine the extent of the patient's surgery, which included removal of both implants, as well as left axillary and right supraclavicular dissection.

A follow-up PET done 3 months postoperatively was normal (Figure 2). At 6 months after surgery, she had no clinical evidence of recurrence.

DISCUSSION

The role of PET in this patient was integral to the course of her care. Conventional imaging (including mammography, ultrasound, and CT) had been unable to identify the recurrence adjacent to the right breast implant, or the spread to the supraclavicular and bilateral axillary lymph nodes. Breast MR was not performed in this patient. Studies comparing the use of ultrasound, mammography, and FDG PET in the detection of breast cancer in patients with breast augmentation have demonstrated FDG PET was able to identify suspicious lesions as cancerous. ^1,2

There was, however, limited information in the literature examining the efficacy of standard radiological modalities (mammography, ultrasound, CT and MR) in evaluating breast cancer spread and recurrence in patients who underwent reconstructive mammoplasy following mastectomy for breast cancer. Azavedo and Boné ³ concluded that MR was the leading technique in imaging silicone breast implants and stated that it would be most suitable for assessing post-reconstruction recurrence when compared with mammography, ultrasound, and CT. Breast MR had emerged initially as an answer to uncertainties presented by the limited mammography and ultrasound studies in the setting of breast implants. Piccoli et al ⁴ stated, however, that MR itself was subject to limitations presented by imaging parameters and contrast agent delivery as well as the menstrual status of the patient and the vascularity of the lesion. These factors adversely affect the ability of MRI to distinguish cancerous lesions in the setting of breast implants.

Furthermore, MR is unable to distinguish benign processes, such as peri-implant inflammation or fibrosis, from malignant ones. Although FDG PET cannot be utilized as a screening tool for asymptomatic patients due to its limited resolution for small tumors, it is very effective as a staging tool. ⁵ Furthermore, it is not affected adversely by breast tissue density, breast surgery, breast augmentation, breast implants, or dysplastic tissue, which can cause false-positive findings on MR. ⁵ The application of PET, was highly effective in this case, after the traditional modalities had been unable to identify the recurrence and metastatic spread in the setting of bilateral mastectomy and implant reconstruction.

FDG PET guided the extent of surgery and was utilized for follow-up surveillance. At 3 months postoperative, the patient was tumor free, as demonstrated by PET, and remains without clinical evidence of recurrence 6 months after surgery. The comparison of existing modalities and PET for follow-up and restaging in patients who have had breast reconstruction with implants after mastectomy for breast cancer bears further study to define more clearly the most suitable method for evaluation, as well as the role of FDG PET in the management of this subgroup of women.

As of October 1, 2002, Medicare will start reimbursing for PET scans for breast cancer staging, restaging, and monitoring of response to therapy. This application, such as shown in this case, will become routine clinical practice and will allow for the early detection of recurrent breast cancer in women with implants.