Abstract
Objectives
Soft tissue sarcoma (STS) is a rare malignancy with a 5 year overall survival rate of 55%. Neoadjuvant radiotherapy is commonly used in preparation for surgery, but methods to assess early response are lacking despite pathological response at surgery being predictive of overall survival, local recurrence and distant metastasis. Multiparametric MR imaging (mpMRI) is used to assess response in a variety of tumours but lacks a robust, standardised method. The overall aim of this study was to develop a feasible imaging protocol to identify imaging biomarkers for further investigation.
Methods
Fifteen patients with biopsy-confirmed STS suitable for preoperative radiotherapy and radical surgery were imaged throughout treatment. The mpMRI protocol included anatomical, diffusion weighted and dynamic contrast-enhanced imaging, giving estimates of apparent diffusion coefficient (ADC) and the area under the enhancement curve at 60 s (iAUC60). Histological analysis of resected tumours included detection of CD31, Ki67, HIF and calculation of a hypoxia score.
Results
There was a significant reduction in T1 at visit 2 and in ADC at visit 3. Significant associations were found between hypoxia and pre-treatment iAUC60, pre-treatment ADC and mid-treatment iAUC60. There was also statistically significant association between mid-treatment ADC and Ki67.
Conclusions
This work showed that mpMRI throughout treatment is feasible in patients with STS having neoadjuvant radiotherapy. The relationships between imaging parameters, tissue biomarkers and clinical outcomes warrant further investigation.
Advances in Knowledge
mpMRI based biomarkers have good correlation with STS tumour biology and are potentially of use for evaluation of radiotherapy response.
Soft tissue sarcoma (STS) is a rare malignancy with a 5 year overall survival rate of 55%. Neoadjuvant radiotherapy is commonly used in preparation for surgery, but methods to assess early response are lacking despite pathological response at surgery being predictive of overall survival, local recurrence and distant metastasis. Multiparametric MR imaging (mpMRI) is used to assess response in a variety of tumours but lacks a robust, standardised method. The overall aim of this study was to develop a feasible imaging protocol to identify imaging biomarkers for further investigation.
Methods
Fifteen patients with biopsy-confirmed STS suitable for preoperative radiotherapy and radical surgery were imaged throughout treatment. The mpMRI protocol included anatomical, diffusion weighted and dynamic contrast-enhanced imaging, giving estimates of apparent diffusion coefficient (ADC) and the area under the enhancement curve at 60 s (iAUC60). Histological analysis of resected tumours included detection of CD31, Ki67, HIF and calculation of a hypoxia score.
Results
There was a significant reduction in T1 at visit 2 and in ADC at visit 3. Significant associations were found between hypoxia and pre-treatment iAUC60, pre-treatment ADC and mid-treatment iAUC60. There was also statistically significant association between mid-treatment ADC and Ki67.
Conclusions
This work showed that mpMRI throughout treatment is feasible in patients with STS having neoadjuvant radiotherapy. The relationships between imaging parameters, tissue biomarkers and clinical outcomes warrant further investigation.
Advances in Knowledge
mpMRI based biomarkers have good correlation with STS tumour biology and are potentially of use for evaluation of radiotherapy response.
| Original language | English |
|---|---|
| Journal | British Journal of Radiology |
| Publication status | Accepted/In press - 5 Jan 2021 |
