Lymphoscintigraphy and Single-Photon Emission Computed Tomography (SPECT)/CT to Determine Need for Second Sentinel Lymph Node Biopsy for Breast Cancer Recurrence Following Ipsilateral Breast/Axillary Surgery.

BACKGROUND For patients with cN0 breast cancer, sentinel node biopsy (SNB) is performed to confirm metastasis. When cancer recurs after a breast/axillary surgery, performing a second SNB is debatable in terms of its accuracy and significance. However, SNB is often performed because it is less invasive and can provide significant information. This report describes our experience of performing lymphoscintigraphy and single-photon emission computed tomography (SPECT)/CT to determine whether SNB is informative or not in patients who develop ipsilateral breast tumor recurrence (IBTR) following a breast/axillary surgery. CASE REPORT We included 9 patients with breast cancer and a history of ipsilateral breast/axillary surgery who underwent lymphoscintigraphy and SPECT/CT between April 2020 and July 2023. For lymphoscintigraphy, 20-25 MBq of 99mTc-phytate was injected subcutaneously in the areola, and planar images and SPECT/CT were taken at 15 min and 3 h after the injection. In lymphoscintigraphy, radioisotope accumulation was detected in 2 patients at 15 min and 8 patients at 3 h; it was not detected in 1 patient. The accumulation site was only the axilla in 3 patients; other sites including the axilla in 3, and sites outside the axilla in 2. CONCLUSIONS When a patient who previously underwent breast/axillary surgery develops IBTR, the initial surgery may have altered the lymphatic flow. The lymphatic flow varied between the contralateral or ipsilateral internal mammary lymph nodes, contralateral axilla, multidirectional flow, and the axilla alone. Lymphoscintigraphy and SPECT/CT may be useful for early determination of the need for another SNB.

Effects of menstrual cycle on background parenchymal enhancement and detectability of breast cancer on dynamic contrast-enhanced breast MRI: A multicenter study of an Asian population.

PURPOSE: To evaluate the effect of the menstrual cycle on BPE and cancer detectability in an Asian population. MATERIAL AND METHODS: 266 premenopausal patients with regular menstrual cycles from 24 centers were included, and 176 of them were diagnosed by pathology as having breast cancer. Thirty-five patients were examined in the menstrual phase (days 1-4), 105 in the proliferative phase (days 5-14), and 126 in the secretory phase (days 15-30). Measurement of the following signal intensities (SIs) were obtained: breast tissue on the unaffected side on a pre-contrast image (SI1) and an early-phase image (SI2); the SIs of breast tissue on the affected side on a pre-contrast image (SI3) and an early-phase image (SI4); and the SIs of breast cancer on a pre-contrast image (SI5) and an early-phase image (SI6). We calculated the BPE ratio, i.e., (SI2- SI1)/SI1 and the cancer/background enhancement ratio (C/B) ratio, i.e., (SI6- SI5) / (SI4- SI3). The BPE was classified as minimal, mild, moderate, or marked, and the cancer detectability was classified as excellent, good, or poor independently by two radiologists. RESULTS: The average C/B ratio was 20.1, 15.7, and 9.1 at the menstrual, proliferative, and secretory phases (p < 0.001). BPE was determined as moderate or marked in 0% and 5.4% at the menstrual phase, 10.3% and 11.0% at the proliferative phase, and 17.5% and 21.7% at the secretory phase by the two observers, respectively (p = 0.01, p = 0.01). The detectability of breast cancer was classified as poor in 0% and 0%, 1.4% and 13.0%, and 8.0% and 22.1% at the menstrual, proliferative, and secretory phases by the two observers, respectively (p = 0.07, p = 0.02). CONCLUSION: The menstrual phase and the proliferative phase seem to be suitable for breast MRI of Asian women.