Textural features on 18F-FDG PET/CT and dynamic contrast-enhanced MR imaging for predicting treatment response and survival of patients with hypopharyngeal carcinoma

Abstract

The utility of multimodality molecular imaging for predicting treatment response and survival of patients with hypopharyngeal carcinoma remains unclear. Here, we sought to investigate whether the combination of different molecular imaging parameters may improve outcome prediction in this patient group.Patients with pathologically proven hypopharyngeal carcinoma scheduled to undergo chemoradiotherapy (CRT) were deemed eligible. Besides clinical data, parameters obtained from pretreatment 2-deoxy-2-[fluorine-18]fluoro-D-glucose positron emission tomography/computed tomography (F-FDG PET/CT), dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI), and diffusion-weighted MRI were analyzed in relation to treatment response, recurrence-free survival (RFS), and overall survival (OS).A total of 61 patients with advanced-stage disease were examined. After CRT, 36% of the patients did not achieve a complete response. Total lesion glycolysis (TLG) and texture feature entropy were found to predict treatment response. The transfer constant (K), TLG, and entropy were associated with RFS, whereas K, blood plasma volume (Vp), standardized uptake value (SUV), and entropy were predictors of OS. Different scoring systems based on the sum of PET- or MRI-derived prognosticators enabled patient stratification into distinct prognostic groups (P <.0001). The complete response rate of patients with a score of 2 was significantly lower than those of patients with a score 1 or 0 (14.7% vs 58.9% vs 75.7%, respectively, P = .007, respectively). The combination of PET- and DCE-MRI-derived independent risk factors allowed a better survival stratification than the TNM staging system (P <.0001 vs .691, respectively).Texture features on F-FDG PET/CT and DCE-MRI are clinically useful to predict treatment response and survival in patients with hypopharyngeal carcinoma. Their combined use in prognostic scoring systems may help these patients benefit from tailored treatment and obtain better oncological results.

Figure 1

Box-whisker plot showing the value of TLG and texture feature entropy on PET for predicting treatment response in patients with primary hypopharyngeal carcinoma treated with chemoradiotherapy. CRs showed significantly lower entropy and TLG values compared with non-complete responders (non-CRs). CRs = complete responders, PET =  positron emission tomography, TLG = total lesion glycolysis.

Figure 2

Scatter plot depicting the distribution of pretreatment texture feature entropy values against TLG values, categorized by the scoring system. Representative PET and MRI images for cases with high (red color) or low (blue color) scores are also shown. (a) A patient with stage T4aN2b hypopharyngeal squamous cell carcinoma (arrow) and a score of 2 based on the treatment response scoring system devised in the present study. (b) An ¹⁸F-FDG PET/CT image depicting the primary tumor, which had an entropy value of 7.11 and (c) a TLG value of 405.21 g/mL × mL. (d) After chemoradiotherapy, the patient still had a residual tumor (arrow) at the locoregional site. (e) An ¹⁸F-FDG PET/CT image of a patient with stage T4aN3 hypopharyngeal squamous cell carcinoma (arrow) and a score of 0. (f) The ¹⁸F-FDG PET/CT image had an entropy value of 6.89 and (g) a TLG value of 110.97 g/mL × mL. (h) The patient achieved complete remission after definitive treatment. CT = computed tomography, MRI = magnetic resonance imaging, PET = positron emission tomography, TLG = total lesion glycolysis.

Figure 3

Kaplan–Meier plots of overall survival in patients with primary hypopharyngeal carcinoma stratified acco rding to our prognostic scoring system (a) and the TNM Staging System (b). The combination of pretreatment texture feature entropy and DCE-MRI parameters enabled a better prognostic stratification than the TNM Staging System (P <.0001 vs .691, respectively). DCE-MRI = dynamic contrast-enhanced MRI.

Figure 4

1. (a) A PET image of a 40-year-old male patient with stage IVa hypopharyngeal squamous cell carcinoma and a score of 4. (b) The ¹⁸F-FDG PET/CT image showed a high primary tumor entropy value (7.217). (c) A left hypopharyngeal tumor was also identified on the corresponding axial-enhanced T1-weighted MRI image. (d) A DCE-MRI image with an overlaid volume transfer rate constant (K^trans) map of the primary tumor exhibited a low value of 0.317 min⁻¹. (e) The patient had a persistent tumor at the locoregional site (arrow) and died 9 months thereafter. 4–2. (a) A positron emission tomography (PET) image of a 58-year-old male patient with stage IVb hypopharyngeal squamous cell carcinoma staging and a score of 1. (b) The ¹⁸F-FDG PET/CT image showed a low entropy value (6.785). (c) The corresponding axial-enhanced T1-weighted MRI also revealed a bulky right hypopharyngeal tumor. (d) The corresponding DCE-MRI with an overlaid volume transfer rate constant (K^trans) map had a high value (0.655 min⁻¹). (e) A post-treatment MRI showed complete remission of the primary tumor. After 60 months of follow-up, the patient is still alive without recurrences. CT = computed tomography, DEC = dynamic contrast-enhanced, MRI = magnetic resonance imaging, PET = positron emission tomography.

Figure 4 (Continued)

1. (a) A PET image of a 40-year-old male patient with stage IVa hypopharyngeal squamous cell carcinoma and a score of 4. (b) The ¹⁸F-FDG PET/CT image showed a high primary tumor entropy value (7.217). (c) A left hypopharyngeal tumor was also identified on the corresponding axial-enhanced T1-weighted MRI image. (d) A DCE-MRI image with an overlaid volume transfer rate constant (K^trans) map of the primary tumor exhibited a low value of 0.317 min⁻¹. (e) The patient had a persistent tumor at the locoregional site (arrow) and died 9 months thereafter. 4–2. (a) A positron emission tomography (PET) image of a 58-year-old male patient with stage IVb hypopharyngeal squamous cell carcinoma staging and a score of 1. (b) The ¹⁸F-FDG PET/CT image showed a low entropy value (6.785). (c) The corresponding axial-enhanced T1-weighted MRI also revealed a bulky right hypopharyngeal tumor. (d) The corresponding DCE-MRI with an overlaid volume transfer rate constant (K^trans) map had a high value (0.655 min⁻¹). (e) A post-treatment MRI showed complete remission of the primary tumor. After 60 months of follow-up, the patient is still alive without recurrences. CT = computed tomography, DEC = dynamic contrast-enhanced, MRI = magnetic resonance imaging, PET = positron emission tomography.