Response rate and diagnostic accuracy of early PET‐CT during neo‐adjuvant therapies in oesophageal adenocarcinoma: A systematic review and meta‐analysis

Abstract

Purpose Only 25% of oesophageal adenocarcinoma (OAC) patients have a pathological response to neo‐adjuvant therapy (NAT) before oesophagectomy. Early response assessment using PET imaging may help guide management of these patients. We performed a systematic review and meta‐analysis to synthesise the evidence detailing response rate and diagnostic accuracy of early PET‐CT assessment. Methods We systematically searched several databases including MEDLINE and Embase. Studies with mixed cohorts of histology, tumour location and a repeat PET‐CT assessment after more than one cycle of NAT were excluded. Reference standard was pathological response defined by Becker or Mandard classifications. Primary outcome was metabolic response rate after one cycle of NAT defined by a reduction in maximum standardised uptake value (SUVmax) of 35%. Secondary outcome was diagnostic accuracy of treatment response prediction, defined as the sensitivity and specificity of early PET‐CT using this threshold. Quality of evidence was also assessed. Random‐effects meta‐analysis pooled response rates and diagnostic accuracy. This study was registered with PROSPERO (CRD42019147034). Results Overall, 1341 articles were screened, and 6 studies were eligible for analysis. These studies reported data for 518 patients (aged 27‐78 years; 452 [87.3%] were men) between 2005 and 2020. Pooled sensitivity of early metabolic response to predict pathological response was 77.2% (95% CI 53.2%‐100%). Significant heterogeneity existed between studies (I2 = 80.6% (95% CI 38.9%‐93.8%), P = .006). Pooled specificity was 75.0% (95% CI 68.2%‐82.5%), however, no significant heterogeneity between studies existed (I2 = 0.0% (95% CI 0.0%‐67.4%), P = .73). Conclusion High‐quality evidence is lacking, and few studies met the inclusion criteria of this systematic review. The sensitivity of PET using a SUVmax reduction threshold of 35% was suboptimal and varied widely. However, specificity was consistent across studies with a pooled value of 75.0%, suggesting early PET assessment is a better predictor of treatment resistance than of pathological response. Further research is required to define optimal PET‐guided treatment decisions in OAC.

A prospective study on the early evaluation of response to androgen receptor-targeted agents with 11C-Choline, 68Ga-PSMA, and 18F-FACBC PET in metastatic castration-resistant prostate cancer: a single-center experience

“… 10 Besides, the imaging evaluation with conventional imaging (CIM), consisting of computed tomography (CT), magnetic resonance imaging, or bone scintigraphy, is not completely able to identify responsive or resistant patients to ARTA. Otherwise, a promising assessment of response to therapy could be carried out with positron emission tomography (PET), as already demonstrated in other cancers, 11 , 12 , 13 also in view of its ability to determine the extent of disease with respect to sites and number of metabolically active lesions.…”

Prospective pilot study utilizing changes in quantitative values obtained on serial fluorine‐18 fluorodeoxyglucose (18F‐FDG) positron emission tomography–computed tomography (PET/CT) in dogs with appendicular osteosarcoma before and after stereotactic body radiation therapy (SBRT) and carboplatin chemotherapy to assess for prediction of survival and therapeutic effectiveness

“…[3][4][5][6][7] In addition, there have been more recent publications that have used follow-up 18 F-FDG PET/CT to assess response in treatment by calculating the percentage change in SUV max , MTV, and/or TLG with varying levels of sensitivity and specificity depending on tumor type and timing of imaging. 3,[8][9][10] There is evidence that serial imaging with 18 F-FDG PET/CT can also be used following radiation in people to determine the treatment success and prognosticate both survival and progression-free intervals. [11][12][13] The use of 18 F-FDG PET/CT is in its relative infancy in veterinary medicine due to limited access to the technology.…”

“…SUV max , MTV, and TLG have all been shown to be prognostic for various tumor types in people when 18 F‐FDG PET/CT is used for staging of naïve cancers 3–7 . In addition, there have been more recent publications that have used follow‐up 18 F‐FDG PET/CT to assess response in treatment by calculating the percentage change in SUV max , MTV, and/or TLG with varying levels of sensitivity and specificity depending on tumor type and timing of imaging 3,8–10 . There is evidence that serial imaging with 18 F‐FDG PET/CT can also be used following radiation in people to determine the treatment success and prognosticate both survival and progression‐free intervals 11–13 …”