Peritumoral ADC values in breast cancer: region of interest selection, associations with hyaluronan intensity, and prognostic significance

Abstract

ObjectivesWe aimed to evaluate the differences in peritumoral apparent diffusion coefficient (ADC) values by four different ROI selection methods and to validate the optimal method. Furthermore, we aimed to evaluate if the peritumor-tumor ADC ratios are correlated with axillary lymph node positivity and hyaluronan accumulation.MethodsAltogether, 22 breast cancer patients underwent 3.0-T breast MRI, histopathological evaluation, and hyaluronan assay. Paired t and Friedman tests were used to compare minimum, mean, and maximum values of tumoral and peritumoral ADC by four methods: (M1) band ROI, (M2) whole tumor surrounding ROI, (M3) clockwise multiple ROI, and (M4) visual assessment of ROI selection. Subsequently, peritumor/tumor ADC ratios were compared with hyaluronan levels and axillary lymph node status by the Mann-Whitney U test.ResultsNo statistically significant differences were found among the four ROI selection methods regarding minimum, mean, or maximum values of tumoral and peritumoral ADC. Visual assessment ROI measurements represented the less time-consuming evaluation method for the peritumoral area, and with sufficient accuracy. Peritumor/tumor ADC ratios obtained by all methods except the clockwise ROI (M3) showed a positive correlation with hyaluronan content (M1, p = 0.004; M2, p = 0.012; M3, p = 0.20; M4, p = 0.025) and lymph node metastasis (M1, p = 0.001; M2, p = 0.007; M3, p = 0.22; M4, p = 0.015), which are established factors for unfavorable prognosis.ConclusionsOur results suggest that the peritumor/tumor ADC ratio could be a readily applicable imaging index associated with axillary lymph node metastasis and extensive hyaluronan accumulation. It could be related to the biological aggressiveness of breast cancer and therefore might serve as an additional prognostic factor.Key Points• Out of four different ROI selection methods for peritumoral ADC evaluation, measurements based on visual assessment provided sufficient accuracy and were the less time-consuming method. • The peritumor/tumor ADC ratio can provide an easily applicable supplementary imaging index for breast cancer assessment. • A higher peritumor/tumor ADC ratio was associated with axillary lymph node metastasis and extensive hyaluronan accumulation and might serve as an additional prognostic factor.

Peritumor to tumor apparent diffusion coefficient ratio is associated with biologically more aggressive breast cancer features and correlates with the prognostication tools

“…The presence of LVI is another well-established prognostic factor in breast cancer [36] and was previously shown to be associated with the presence of peritumoral edema [37]. LVI was significantly associated with a higher peritumor/tumor ADC ratio in this study, which is consistent with previous results [4,14].…”

“…Three round ROIs (4 pixels per ROI) were then placed on the peritumoral breast parenchymal tissue adjacent to the tumor border at locations at which the ADC values appeared (visually) to be most strongly increased [4,14]. The mean ADC values were recorded for each ROI, and the highest value among the three was designated the peritumor ADC.…”

“…Although the details of the biologic mechanisms underlying the presence of peritumoral edema remains unclear, it is suggested that proteolysis and neoangiogenesis associated with invasive growth and tumor progression triggers the release of cytokines and an increase of vascular permeability, which consequently induces transudation of fluid in the peritumoral area [2]. Several studies have shown that peritumoral edema is associated with tumor aggressiveness and worse prognosis [3][4][5]. Also, gene signature in the peritumoral stroma has been shown to be distinct from that of the tumoral stroma [6][7][8].…”

“…To reduce the effects of possible equipment-related confounding factors, the peritumor/tumor ADC ratio may be a more reliable and generally more applicable tool than just the tumoral or peritumoral areas. However, few studies have examined the associations between the peritumor/tumor ADC ratio and the biological and histological features of breast cancers [4,14]. Furthermore, the overall prognostication value of the peritumor/tumor ADC ratio remains unclear.…”

Detection of Breast Region of Interest via Breast MR Scan on an Axial Slice

“…22 breast cancer patients are included to the study. The study shows that there is no statistically significant difference among the four ROI selection methods [8].…”