Abstract
ObjectiveTo investigate the changes of three-dimensional apparent diffusion coefficient (3D-ADC) of bilateral parotid glands during radiotherapy for head and neck squamous cell carcinoma (HNSCC) patients and explore the correlations with the radiation dose, volume reduction of parotid gland and the salivary secretary function.Materials and Methods60 HNSCC were retrospectively collected in Sichuan cancer hospital. The patients were all received diffusion-weighted imaging (DWI) scan at pre-radiation, the 15th radiation, the 25th radiation and completion of radiation. Dynamic 3D-ADC were measured in different lobes of parotid glands (P1: deep lobe of ipsilateral; P2: superficial lobe of ipsilateral; P3: deep lobe of contralateral; P4: superficial lobe of contralateral), and the 3D-ADC of spinal cord were also recorded. Chewing stimulates test, radionuclide scan and RTOG criteria were recorded to evaluate the salivary secretary function. Pearson analysis was used to assess the correlation between 3D-ADC value, radiation dose, volume change, and salivary secretary function.ResultsThe mean 3D-ADC of parotid glands increased. It began to change at the 15th radiation and the mostly increased in P1. However, there was no change for the maximum and minimum 3D-ADC. The 3D-ADC values of spinal cord changes were almost invisible (ratio ≤ 0.03 ± 0.01). The mean 3D-ADC was negatively correlated with the salivary secretary function (r=-0.72) and volume reduction of different lobes of parotid glands (r1=-0.64; r2=-0.61; r3=-0.57; r4=-0.49), but it was positively correlated with the delivered dose (r1 = 0.73; r2 = 0.69; r3 = 0.65; r4 = 0.78).ConclusionDynamic 3D-ADC changes might be a new and early indicator to predict and evaluate the secretary function of parotid glands during radiotherapy.
Highlights
Approximate 500,000 new head and neck cancer (HNC) patients occur worldwide annually
The mean 3D-ADC was negatively correlated with the salivary secretary function (r=-0.72) and volume reduction of different lobes of parotid glands (r1=0.64; r2=-0.61; r3=-0.57; r4=-0.49), but it was positively correlated with the delivered dose (r1 = 0.73; r2 = 0.69; r3 = 0.65; r4 = 0.78)
The chewing stimulating test indicated that the mean salivary production decreased gradually at pre-Radiation therapy (RT), 15th fraction, 25th fraction, and the completion of RT (Figure 1)
Summary
Approximate 500,000 new head and neck cancer (HNC) patients occur worldwide annually. Radiation therapy (RT), as the main non-surgical treatment, is used for over 70% patients with squamous cell carcinoma of the head and neck (HNSCC). Radiationinduced xerostomia remains a common side effect and severely affects patients’ quality of life [1]. IMRT may reduce radiation dose to the parotid glands to some extent, radiationinduced xerostomia cannot be avoided. A recent study reported the severe xerostomia was observed at week 7 and 8 after starting RT, and 79% of patients had grade 2 xerostomia. Another study reported severe xerostomia was observed in patients at one month after radiation therapy and had difficulty in collecting enough amount of saliva for analysis [4]. It is important to predict the secretary function of parotid glands during radiotherapy, and it might reduce xerostomia by adjusting RT plan and/or use some particular drug in an early stage
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
