Abstract P3-03-02: The metastatic rate of IMLN, when IMLN metastasis is suspected with PET CT.

Abstract

Abstract Background: Metastatic status of internal mammary lymph nodes (IMLNs) has a clinical importance in assessing stage and prognosis of breast cancer. But, when metastasis of IMLN is suspected, the management is controversial. We reviewed 29 breast cancer patients who had IMLN dissection, retrospectively, and investigated the pathologic status of IMLNs. Methods: From August 2005 to December 2011, at Yeungnam University Hospital, 43 patients underwent IMLN biopsy or dissection for suspected IMLN metastasis on lymphoscintigraphy (7 patients), breast ultrasound (1 patient) or PET CT (29 patients), when diagnosed with primary or recurred breast cancer. 6 patients who had stage IV at diagnosis or had too obscure data to identify exact location of IMLN, were excluded. Among them, we reviewed clinicopathologic features of IMLN detected on PET CT and metastatic status of IMLNs was investigated. Results: Total 29 patients were included in this study. 19 patients and 10 patients underwent IMLN dissection when diagnosed with primary or recurred breast cancer, respectively. Unlike conventional IMLN dissections, our IMLN biopsy or dissection was done during Radical mastectomy (in 2 pts.), modified radical mastectomy (in 14 pts.), using incision of breast conserving surgery (in 3 pts.) and separated incision (in 10 pts.), with or without resection of ribs. The mean number of IMLNs was 2.76±2.15 and total metastatic rate of IMLN was 72.4% (21/29). The sensitivity, specificity, positive predictive value, and negative predictive value of PET CT was following: 91.3%, 42.8%, 72.4% and 27.6%. Mean standard uptake value (SUV) of metastatic and non-metastatic IMLN were 3.6±2.9 and 3.9±2.6 and there was no statistical difference (p-value=0.821). During IMLN dissection, besides initial approach intercostals space (ICS), some metastatic IMLN was also found in upper or lower level ICS (42.9%, 6/14). Only IMLN metastasis without axillary nodes metastasis were found in 3 patients and the tumor location of these patients was all inner or central quadrant. Chest X-ray was done postoperatively as routine procedure, and there were no other specific complications such as pneumothorax or hemothorax. Conclusion: IMLN dissection without radical mastectomy can be done safely without complications due to recent advance in diagnostic and surgical skills. If SUV on IMLN is shown on the PET-CT, IMLN dissection is needed, regardless of SUV. If breast cancer is located at inner quadrant, more aggressive dissection of IMLN is needed. Further follow-up and studies are needed to assess locoregional recurrence and to compare improvement in overall survival and disease free survival. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-03-02.