Background: Fat necrosis is a subjective early as well as delayed complication, which sometimes mimics local recurrence and ruins the quality of life by pain and poor cosmetic result. While, the frequency and severity of fat necrosis are important issues that breast surgeons should explain to the patient, these data are not revealed well.
Methods: A total of 1476 patients who underwent breast surgery from January 2000 to December 2012 were enrolled in the present study. We assessed fat necrosis by mammographic and physical findings and created grading criteria: Grade (G) 0, no fat necrosis; G1, no symptomatic fat necrosis (mammographic dystrophic calcification); G2, mild symptomatic necrosis (mammographic dystrophic necrosis with tumor); G3, severe symptomatic necrosis (mammographic dystrophic necrosis with pain or skin change); and G4, symptomatic necrosis requiring surgical intervention.
Results: Of the 1476 patients enrolled, 393 (27%) underwent mastectomy, and 1083 (73%) underwent breast-conserving surgery. We achieved a high rate of breast-conserving surgery at a total rate of 73% over the study period and maximum rate of 88% in 2010, using oncoplastic procedures. We mainly adopted a pedicled fat flap (417/1083; 39%) and a free dermal fat flap (40/1083; 3.7%). Among the 626 patients who underwent partial resection with no replacement for the defect, G1-G2 fat necrosis was seen in 29/626 (4.6%). While, the incidence of fat necrosis with pedicled fat flap and free dermal fat graft was 68/417 (16%) and 40/40 (100%), respectively, showing a significant difference (p < 0.01). Furthermore, the incidence of G3-G4 fat necrosis was significantly higher with free dermal fat grafts (25%; 10/40) than with pedicled flap (2.9%; 12/417) (p < 0.01). Among pedicled flaps, the incidence of fat necrosis with inframammary adipofascial flaps was 56% (14/25) which was higher than that with lateral epidermal fat flaps (12%; 33/276) (p < 0.01), and rotation of surrounding breast tissues (8%; 21/116) (p < 0.01). The incidence of G3 fat necrosis was also high at 20% (5/25) in inframammary adipofascial flaps.
Conclusions: Breast-conserving oncoplastic surgery carries a risk of fat necrosis as a delayed complication. The incidence rate and severity of fat necrosis with each procedure should be assessed. We should select fat grafts with a good blood supply to replace defects of breast-conserving therapy.
Keywords: Breast-conserving oncoplastic surgery; Fat necrosis; Free dermal fat flap; Pedicled fat flap.