The accuracy of breast MRI radiomic methodologies in predicting pathological complete response to neoadjuvant chemotherapy: A systematic review and network meta-analysis.

BACKGROUND: Achieving pathological complete response (pCR) to neoadjuvant chemotherapy (NAC) improves survival outcomes for breast cancer patients. Currently, conventional histopathological biomarkers predicting such responses are inconsistent. Studies investigating radiomic texture analysis from breast magnetic resonance imaging (MRI) to predict pCR have varied radiomic protocols introducing heterogeneity between results. Thus, the efficacy of radiomic profiles compared to conventional strategies to predict pCR are inconclusive. PURPOSE: Comparing the predictive accuracy of different breast MRI radiomic protocols to identify the optimal strategy in predicting pCR to NAC. MATERIAL AND METHODS: A systematic review and network meta-analysis was performed according to PRISMA guidelines. Four databases were searched up to October 4th, 2021. Nine predictive strategies were compared, including conventional biomarker parameters, MRI radiomic analysis conducted before, during, or after NAC, combination strategies and nomographic methodology. RESULTS: 14 studies included radiomic data from 2,722 breast cancers, of which 994 were used in validation cohorts. All MRI derived radiomic features improved predictive accuracy when compared to biomarkers, except for pre-NAC MRI radiomics (odds ratio [OR]: 0.00; 95 % CI: -0.07-0.08). During-NAC and post-NAC MRI improved predictive accuracy compared to Pre-NAC MRI (OR: 0.14, 95 % CI: 0.02-0.26) and (OR: 0.26, 95 % CI: 0.07-0.45) respectively. Combining multiple MRIs did not improve predictive performance compared to Mid- or Post-NAC MRIs individually. CONCLUSION: Radiomic analysis of breast MRIs improve identification of patients likely to achieve a pCR to NAC. Post-NAC MRI are the most accurate imaging method to extrapolate radiomic data to predict pCR.

Optimal reconstructive strategies in the setting of post-mastectomy radiotherapy - A systematic review and network meta-analysis.

BACKGROUND: A third of breast cancer patients require mastectomy. In some high-risk cases postmastectomy radiotherapy (PMRT) is indicated, threatening reconstructive complications. Several PMRT and reconstruction combinations are used. Autologous flap (AF) reconstruction may be immediate (AF→PMRT), delayed-immediate with tissue expander (TE [TE→PMRT→AF]) or delayed (PMRT→AF). Implant-based breast reconstruction (IBBR) includes immediate TE followed by PMRT and conversion to permanent implant (PI [TE→PMRT→PI]), delayed TE insertion (PMRT→TE→PI), and prosthetic implant conversion prior to PMRT (TE→PI→PMRT). AIM: Perform a network metanalysis (NMA) assessing optimal sequencing of PMRT and reconstructive type. METHODS: A systematic review and NMA was performed according to PRISMA-NMA guidelines. NMA was conducted using R packages netmeta and Shiny. RESULTS: 16 studies from 4182 identified, involving 2322 reconstructions over three decades, met predefined inclusion criteria. Studies demonstrated moderate heterogeneity. Multiple comparisons combining direct and indirect evidence established AF-PMRT as the optimal approach to avoid reconstructive failure, compared with IBBR strategies (versus PMRT→TE→PI; OR [odds ratio] 0.10, CrI [95% credible interval] 0.02 to 0.55; versus TE→PMRT→PI; OR 0.13, CrI 0.02 to 0.75; versus TE→PI→PMRT OR 0.24, CrI 0.05 to 1.05). PMRT→AF best avoided infection, demonstrating significant improvement versus PMRT→TE→PI alone (OR 0.12, CrI 0.02 to 0.88). Subgroup analysis of IBBR found TE→PI→PMRT reduced failure rates (OR 0.35, CrI 0.15-0.81) compared to other IBBR strategies but increased capsular contracture. CONCLUSION: Immediate AF reconstruction is associated with reduced failure in the setting of PMRT. However, optimal reconstructive strategy depends on patient, surgeon and institutional factors. If IBBR is chosen, complication rates decrease if performed prior to PMRT. PROSPERO REGISTRATION: CRD 42020157077.