Clinical utility of MRI in the neoadjuvant management of early-stage breast cancer.

BACKGROUND: With the increasing use of neoadjuvant treatment (NAT) for patients with early-stage breast cancer (ESBC), adequate clinical staging is essential to inform treatment. While the use of MRI with NAT has been proposed to help with accuracy of pre-treatment clinical staging, its impact in clinical practice remains controversial. METHODS: A prospective institutional database of patients with ESBC treated with NAT between May 2012 and December 2020 was analyzed in order to compare the management of patients who received an MRI prior to NAT to those who did not. The indications for MRI and correlation of MRI findings to conventional breast imaging were evaluated. The impact of MRI on management was compared between the MRI and non-MRI groups. RESULTS: A total of 530 patients met inclusion criteria. Of these, 186 (35.1%) had an MRI and 344 (64.9%) did not. The most frequent indication for MRI was the determination of disease extent (54.5%). Patients who had an MRI prior to neoadjuvant treatment were significantly more likely to be younger (47 years versus 57 years; p < 0.001) and have multifocal disease (32.3% versus 22.1%; p < 0.05). When compared to conventional imaging, MRI reported a greater extent of disease in the breast (37.6%), more nodal involvement (18.8%), and multifocal disease (15.1%). Additional diagnostic interventions were advised in 52.2% of patients who underwent MRI. Rates of mastectomies were greater in the MRI group (80.0% versus 58.9%; p < 0.05) in addition to more axillary dissections (28.0% versus 17.4%; p < 0.01). Rates of locoregional recurrences were low in both groups, with similar disease-free survival outcomes at 5 years. CONCLUSION: MRI identified significantly more disease in contrast to conventional imaging and lead to more aggressive surgical management. Prospective studies evaluating the role of MRI before NAT and its impact on long-term outcomes are needed.

Impact of Recurrence Score on type and duration of chemotherapy in breast cancer.

Background: The use of Oncotype dx (Genomic Health, Redwood City, CA, U.S.A.) testing has been shown to change treatment decisions in approximately 30% of breast cancer (bca) cases, but research on how Recurrence Score testing has affected the type of chemotherapy offered is limited. We sought to determine if the availability of Oncotype dx testing resulted in a change to the type and duration of chemotherapy regimens used in the treatment of early-stage hormone receptor-positive bca. Methods: In a population-based cohort study, patients treated in the 2 years before the availability of Oncotype dx testing were compared with patients treated in the 2 years after testing availability. Charts were audited and divided into 2 groups: pre-Oncotype dx and post-Oncotype dx. The groups were compared for differences in duration of chemotherapy (12 weeks vs. >12 weeks), types of agents used (anthracycline vs. non-anthracycline), and myelosuppressive potential of the chosen regimen. Results: Of 834 patients who fulfilled the enrolment criteria, 360 fell into the pre-Oncotype dx era, and 474, into the post-Oncotype dx era. An increase of 11.2 percentage points, to 69.5% from 58.3%, was observed in the proportion of patients receiving short-course compared with long-course chemotherapy (p = 0.068). The proportion of patients prescribed anthracycline-containing regimens declined in the post-Oncotype dx era (47.7% pre vs. 32.2% post, p = 0.016). The selection of more-myelosuppressive chemotherapy protocols increased in the post-Oncotype dx era (67.4% pre vs. 78.8% post, p = 0.044). Conclusions: In the present study, the availability of Oncotype dx testing was observed to influence the choice of chemotherapy type in the setting of early-stage bca.

Tyrosine kinase inhibitors significantly improved survival outcomes in patients with metastatic gastrointestinal stromal tumour: a multi-institutional cohort study.

Background: The real-world impact of tyrosine kinase inhibitors (tkis) in clinical practice for gastrointestinal stromal tumour (gist) has not been extensively reported. We sought to assess how outcomes have changed over the eras and to evaluate the effect of access to imatinib and sunitinib on survival in patients with unresectable or metastatic gist in British Columbia. Methods: Patients with metastatic or unresectable gist were allocated to one of three eras: pre-2002, 2002-2007, and post-2007 based on treatment availability (pre-imatinib, post-imatinib, and post-sunitinib). Overall survival (os) and progression-free survival (pfs) were compared between eras. Univariate and multivariate analyses were performed to determine the effects of tumour, patient, and treatment characteristics on survival outcomes. Results: Of 657 patients diagnosed with gist throughout British Columbia during 1996-2016, 196 had metastatic disease: 23 in the pre-imatinib era, 67 in the post-imatinib era, and 106 in the post-sunitinib era. A significant increase in os, by 53.6 months (p = 0.0007), and pfs, by 29.1 months (p = 0.044), was observed after the introduction of imatinib. The introduction of sunitinib did not significantly affect os or pfs. Conclusions: Implementation of tkis has drastically improved survival outcomes for patients with metastatic gist by up to 4.55 years in the real-world setting. Our study demonstrates that implementation of tkis in clinical practice has outperformed their benefit predicted in clinical trials.