99mTc-sestamibi scintigraphy used to evaluate tumor response to neoadjuvant chemotherapy in locally advanced breast cancer: A quantitative analysis

Abstract

Abstract. to evaluate the tumor response to neoadjuvant chemotherapy, 99m tc-sestamibi breast scintigraphy was proposed as a quantitative method. Fifty-five patients with ductal carcinoma were studied. they underwent breast scintigraphy before and after neoadjuvant chemotherapy, along with clinical assessment and surgical specimen analysis. the regions of interest on the lesion and contralateral breast were identified, and the pixel counts were used to evaluate lesion uptake in relation to background radiation. the ratio of these counts before to after neoadjuvant chemotherapy was assessed. the decrease in uptake rate due to chemotherapy characterized the scintigraphy tumor response. the Kruskal-Wallis test was used to compare the mean scintigraphic tumor response and histological type. Dunn's multiple comparison test was used to detect differences between histological types. the MannWhitney test was used to compare means between quantitative and qualitative variables: scintigraphic tumor response vs. clinical response and uptake before chemotherapy vs. scintigraphic tumor response. the spearman's test was used to correlate the quantitative variables of clinical reduction in tumor size and scintigraphic tumor response. All of the variables compared presented significant differences. The change in 99m tc-sestamibi uptake noted on breast scintigraphy, before to after neoadjuvant chemotherapy, may be used as an effective method for evaluating the response to neoadjuvant chemotherapy, since this quantification reflects the biological behavior of the tumor towards the chemotherapy regimen.Furthermore, additional analysis on the uptake rate before chemotherapy may accurately predict treatment response. IntroductionBreast cancer is the second most common type of cancer worldwide and the most common among women. It accounts for approximately 22% of new cancer cases among women each year (1), and the 5-year survival rate among the worldwide population is 61%. this high mortality rate is related to late diagnosis, with the presence of tumors of large dimensions and lymph node metastases.locally advanced breast cancer comprises tumors greater than 5 cm in diameter, with wall or skin invasion, metastases to fixed lymph nodes (2,3) and inflammatory carcinoma. treatment for this is multidisciplinary, consisting of preoperative chemotherapy, surgery, radiotherapy and postoperative chemotherapy (4-6).Preoperative or neoadjuvant chemotherapy is standard treatment for individuals with locally advanced breast cancer (7-10). It has been found to substantially improve the survival of these patients (6,11,12). It provides better local control over the disease, with increased likelihood that the breast surgery will be conservative (4,5,13). Moreover, this type of chemotherapy treats preexisting microscopic systemic disease and enables the evaluation of tumor resistance in vivo (14). reduction in tumor volume has been used as the standard criterion for response evaluation among solid tumors such as breast carcinoma (15). techniques tha...

Monitoring the Response to Neoadjuvant Chemotherapy in Breast Cancer

“…Koga et al [65], Wilczek et al [70] showed a significant reduction rate of tumor: back-ground after completion of neoadjuvant chemotherapy, confirmed by tumor regression in histological study of the surgical specimen.…”

“…A better response to chemotherapy regimen was observed in more aggressive tumors that represent a higher uptake rate reduction. The tumor necrosis resulting from chemotherapy could explain the substantial reduction in tumor size [65]. The invasive ductal carcinoma presents a higher uptake rate reduction compared to those associated to the in situ component.…”

“…Koga et al [65], Mankoff et al [67], Marshall et al [68] and Cwikla et al [69] reported a reduction of the rate of tumor:background, showing that the concentration of 99m Tc-sestamibi reflects the metabolic activity of the tumor and its reduction resulting from chemotherapy [68]. Koga et al [65], Wilczek et al [70] showed a significant reduction rate of tumor: back-ground after completion of neoadjuvant chemotherapy, confirmed by tumor regression in histological study of the surgical specimen.…”

“…Tc-sestamibi scintigraphy is shown to be an additional tool for evaluating the preoperative chemotherapy response, given that the variation in 99m Tc-sestamibi uptake reflects the biological behavior of the tumor [65]. …”

“…In the study of Koga et al [65], the quantification of 99m Tc-sestamibi uptake is done on the lateral images of the breasts by creating two identical areas of interest: one on the tumor and the other in the mirror position on the contralateral breast. Pixel counting is performed in these areas (Figure 11).…”