TRAM and DIEP flap reconstruction methods create additional difficulties. In a retrospective study of patients with recurring breast cancer who had undergone TRAM flap reconstruction after initial diagnosis as part of their treatment course, findings were consistent with similar studies in which TRAM flap breast reconstruction was shown to be a safe surgical method that does not raise the statistical recurrence of breast cancer significantly.2 It remained within the average recurrence rate of 2% to 4%.1 The challenge is that half of all recurring cancers mimicked the imaging findings of benign lesions presenting a differential diagnosis.1 In the other half, imaging findings showed malignancies.1 Little information is available on the recurrence rate of breast cancer in patients using the less invasive method of DIEP flap reconstruction, possibly because of its more recent introduction.7 Findings demonstrate similarities in the appearance of recurring breast cancer. The locations of recurring tumors more often are superficial—below the dermis and in the posterior area along the chest wall. This presentation is common to TRAM and DIEP flap reconstruction techniques (see Figure).1 Despite challenges, alternative diagnostic tools can be used for detecting postsurgical recurring breast cancer.
Magnetic Resonance Imaging
ASCO 2012 guidelines recommend routine clinical examination and follow-up with mammography for surveillance in the adjuvant setting.1 However, for lesions presenting deep in the muscle layer or in proximity to a surgical scar or the axilla, physical examination and mammography are limited in diagnosing recurrence effectively.4 In the presence of a recurring cancer, magnetic resonance (MR) imaging is useful to differentiate benign vs malignant disease presentation because of a higher tissue sensitivity (99%) when compared to mammography (33%).8 Nevertheless, MR imaging is not without drawbacks, including inhomogeneous fat suppression or altogether failure of fat suppression.4 In addition, in a study of 969 women, MR imaging results provided false diagnosis of recurring breast cancer in 91 women when compared with pathology results of their benign lesions; therefore, routine breast MR surveillance might expose patients to additional biopsies for benign lesions.8
Benefits of MR imaging include the ability to differentiate between benign lesions, such as fat necrosis, skin thickening, seroma, and hematoma,4 vs malignant lesions presenting in the reconstructed breast. According to one study, recurring cancer appears most often in the underlying dermal layer of the conserved breast tissue.1 Yoo et al describes the recurrence in the following manner:
[S]uperficial recurrence may be explained by the dermal lymphatic systems of the breast. The centripetal nature of lymphatic drainage in the breast may have transferred tumour cells to the dermal layer of native skin, consequently leading to the proliferation of residual carcinoma in the superficial dermal layer and the subcutaneous fat layer.1
Fludeoxyglucose Positron Emission Tomography
Studies have determined the usefulness of fludeoxyglucose positron emission tomography (FDG-PET) scans as an adjunct tool in detecting recurring breast cancer, but the studies reviewed considered only cases in which the patients already had a suspected positive recurrence. With regard to its efficacy as an imaging and diagnostic tool in routine breast cancer surveillance of asymptomatic patients, no prospective studies have demonstrated an effect on survival, quality of life, or cost-effectiveness in the adjuvant follow-up setting.8
Computed tomography and ultrasonography, although useful as adjuncts to mammography, as well as FDG-PET, have not had a significant effect on outcomes for patients with recurring breast cancer.8
Conclusion
The challenges of detecting and diagnosing postsurgical breast cancer recurrence are met successfully using a variety of imaging tools. In these patients, recurrence occurs in the superficial underlying dermal layer of the conserved breast tissue (87.5%) and the deep chest wall (12.5%).1 Common to these areas are remnant cells that might be susceptible to disease because of the nature of the lymphatic system specific to the breast itself. The superficial nature of tumors that might arise in the subdermal layer of the breast demonstrates the importance of breast self-examination as recommended by ASCO because early detection is the most important factor in survivability. In addition, MR imaging specifically, has the ability to evaluate and detect recurring breast cancer; it also has increased specificity to differentiate between benign and malignant lesions. However, MR is a fallible tool and its use can lead to additional procedures, such as biopsy, to prove malignancy of suspected lesions. Therefore, clinical recommendations should align with ASCO recommendations for follow-up of asymptomatic patients. However, if imaging challenges present after cosmetic surgical reconstruction, alternate imaging options do exist. Research shows a variety of methods for clinical follow-up of symptomatic patients depending on provider and institutional protocols. Future studies specifically analyzing whether standardization of protocols in suspected breast cancer recurrence affects survival rates might shed important information on this aspect of clinical care.