The Role of redo-Sentinel Lymph Node Biopsy in Patients With Prior Ipsilateral Breast Cancer Surgery.

BACKGROUND: Sentinel Lymph Node Biopsy (SLNB) is used to stage the axilla, but there is limited data in patients with prior ipsilateral breast cancer. This study compares redo-SLNB (reSLNB) and Axillary node sample (ANS) in this sub-cohort of patients. MATERIALS AND METHODS: This is a retrospective study looking at patients with a new ipsilateral primary or recurrence with history of breast-conserving surgery. Planned and performed surgery, patient demographics and previous treatments were recorded. Node positivity and success rate of reSLNB was analyzed. RESULTS: A total of 86 patients were identified that had mastectomy for ipsilateral recurrent disease with radiologically negative axilla. Out of the 48 that had reSLNB, 35(72.9%) were successful. Nineteen percent of the reSLNB had positive axillae and 20% of the ANS patients. reSLNB success rate was significantly lower amongst patients with previous axillary surgery (P = .014) and previous positive nodes(P = .001). CONCLUSION: reSLNB should be considered to restage the axilla in patients with previous history of ipsilateral cancer especially that there is growing evidence showing good identification rate.

Detectability of small objects in PET/computed tomography phantom images with Bayesian penalised likelihood reconstruction.

OBJECTIVES: This study investigated the subcentimetre lesion detection gains of a Bayesian penalised likelihood reconstruction (BPLR) (Q.Clear, GE Healthcare, Milwaukee, USA) in PET/computed tomography (CT) phantom images and compares observer performance with ordered subset expectation maximisation (OSEM) reconstruction images (VUE Point HD, GE Healthcare). METHODS: Images were presented to three blinded experienced observers to identify lesions and assign confidence ratings. Responses were analysed using jackknife alternative free receiver operator characteristic (JAFROC) software. Phantom lesions (active and nonactive) were constructed using putty. Seventy nonactive and 93 (F) active lesions, with diameters of 3, 5 or 7 mm were suspended in active backgrounds at varying contrast ratios (2:1-32:1) within an National Electrical Manufacturers Association 2012 phantom. PET/CT images were acquired with a GE Discovery 710 and reconstructed using both BPLR (penalisation coefficient 400) and high-definition attenuation corrected (HDAC) OSEM (2 iterations, 24 subsets). RESULTS: Small but significant (P = 0.009) visual detection gains were seen for active lesions with BPLR [weighted JAFROC figure of merit (wJAFROC FOM) = 0.77] over OSEM (FOM = 0.74). When split by subset, these improvements were significant for 5 mm and lesion to background ratio of 8:1. No significant (P = 0.514) differences were seen for the identification of nonactive lesions of any size (BPLR FOM = 0.74 and OSEM FOM = 0.73). CONCLUSIONS: Significant detection gains were demonstrated for small active lesions with BPLR over OSEM. Coupled with the significant increase in contrast-to-noise ratio, these results support the use of BPLR in the imaging of small active (≤7 mm) lesions but show no improvement with BPLR in the identification of true negative lesions.