Table 3.
Ridge regression analyses demonstrating the complementary value of 18F-FDG PET/CT and DW-MRI parameters with pathologic complete response (TRG 1) and good response (TRG 1–2) as outcome variables.
| pCR (TRG 1) | GR (TRG 1 +2) | ||||
|---|---|---|---|---|---|
| Predictors | Odds ratio | Optimism-corrected c-statistic (95% bootstrapped CI) | Predictors | Odds ratio | Optimism corrected c-statistic (95% bootstrapped CI) |
| Model 1: Histology | |||||
| Squamous cell carcinoma† | 8.23 | 0.66 (0.53 – 0.78)* | Squamous cell carcinoma† | 7.81 | 0.60 (0.52 – 0.67)* |
| Model 2: DW-MRI parameter and histology | |||||
| ΔADCduring (%) | 1.04 | 0.81 (0.70 – 0.93)* | ΔADCduring (%) | 1.08 | 0.83 (0.73 – 0.92)* |
| Squamous cell carcinoma† | 4.56 | Squamous cell carcinoma† | 2.95 | ||
| Model 3:18F-FDG PET/CT parameter and histology | |||||
| ΔSUVmean,post (%) | 0.98 | 0.79 (0.67 – 0.90)§ | ΔSUVmax,during (%) | 0.99 | 0.74 (0.60 – 0.88)¶ |
| Squamous cell carcinoma† | 3.90 | Squamous cell carcinoma† | 3.12 | ||
| Model 4: DW-MRI and 18F-FDG PET/CT parameters and histology | |||||
| ΔADCduring (%) | 1.03 | 0.83 (0.74 – 0.94)§ | ΔADCduring (%) | 1.06 | 0.82 (0.75 – 0.94)¶ |
| ASUVmean,post (%) | 0.98 | ΔSUVmax,during (%) | 0.99 | ||
| Squamous cell carcinoma† | 3.19 | Squamous cell carcinoma† | 3.14 | ||
ADC apparent diffusion coefficient; CI confidence interval; c-statistic concordance statistic; GR good response (TRG 1–2); pCR pathologic complete response; SUV standardized uptake value.
Analyses based on 68 patients of whom 17 had pCR (TRG 1) and 42 had GR (TRG 1–2). The applied exclusion criterion was histology other than adenocarcinoma or squamous cell carcinoma (n=1).
Analyses based on 64 patients of whom 16 had pCR (TRG 1). Exclusion criteria were no post-treatment 18F-FDG PET/CT available (n=3), no uptake on post-treatment 18F-FDG PET/CT (n=1) and histology other than adenocarcinoma or squamous cell carcinoma (n=1).
Analyses based on 67 patients of whom 41 had GR (TRG 1–2). Exclusion criteria were no 18F-FDG PET/CT available during treatment (n=1) and histology other than adenocarcinoma or squamous cell carcinoma (n=1).
Adenocarcinoma was used as reference category.
Note. For the analyses of good response only 18F-FDG PET/CT and DW-MRI parameters acquired during neoadjuvant chemoradiotherapy were included in the analyses considering the relevance of the research question. Regression coefficients and intercepts of all models are included in the supplementary file.