Clinical Scorecard: Predictive Value of Serial Multiparametric MRI and FDG-PET/CT Imaging Changes During Radiation Therapy for Treatment Outcomes in Head and Neck Cancer Patients

At a Glance

Key Highlights

• Conventional prognostic markers (TNM stage, smoking history, HPV status) are insufficient for predictive risk-adaptation in head and neck cancer treatment.
• Serial multiparametric MRI (DWI) and FDG-PET/CT imaging during radiotherapy provide complementary quantitative biomarkers that better predict treatment response than pre-treatment imaging alone.
• Optimal timing for mid-treatment imaging assessment remains undetermined; this study evaluates serial imaging at multiple time points during radiotherapy to identify predictive changes.

Guideline-Based Recommendations

Diagnosis

• Use biopsy-proven diagnosis of mucosal head and neck squamous cell carcinoma.
• Perform baseline multiparametric MRI (including DWI) and FDG-PET/CT prior to radiotherapy.

Management

• Treat with definitive radiotherapy using simultaneous integrated boost intensity-modulated radiation therapy over 35 fractions.
• Consider concurrent systemic therapy as appropriate.
• Use serial functional imaging (DWI MRI at weeks 2, 3, 5, 6; FDG-PET/CT at baseline and week 3) to monitor tumor response during treatment.

Monitoring & Follow-up

• Evaluate treatment response with post-treatment FDG-PET/CT and clinical examination including nasoendoscopy.
• Confirm recurrences histologically or via imaging with multidisciplinary team review.
• Calculate percentage changes in ADCmean from DWI and metabolic tumor volume (MTV), SUVmax, SUVmean, and total lesion glycolysis (TLG) from FDG-PET/CT relative to baseline.

Risks

• Recognize that despite treatment, locoregional tumor recurrence remains a significant risk.
• Be aware of acute and late toxicities associated with radiotherapy and systemic treatments.

Patient & Prescribing Data

Non-metastatic mucosal head and neck squamous cell carcinoma patients undergoing definitive radiotherapy

Serial imaging biomarkers (DWI and FDG-PET/CT) during radiotherapy may guide adaptive treatment intensification or de-intensification based on early tumor response, potentially improving outcomes and reducing toxicity.

Clinical Best Practices

• Incorporate multidisciplinary team evaluation for treatment planning and response assessment.
• Use standardized imaging protocols and consistent scanner settings for serial MRI and PET/CT to ensure reliable quantitative comparisons.
• Delineate tumor volumes on ADC maps referencing low b-value diffusion images and co-registered T2-weighted MRI for accuracy.
• Utilize semi-automated gradient methods (e.g., PETedge) for metabolic tumor volume delineation on PET images.
• Calculate and monitor percentage changes in functional imaging parameters from baseline to identify early treatment response.
• Perform post-treatment imaging and clinical follow-up to confirm treatment outcomes and detect recurrences.

References

• Head and Neck Cancer Prognostic Markers and Imaging Biomarkers
• EANM Clinical Guidelines for FDG-PET/CT Imaging
• PyRadiomics Open-Source Radiomic Feature Extraction
• Consensus Recommendations for DWI Tumor Delineation