PURPOSE: Irradiation of the parotid glands causes salivary dysfunction, resulting in reduced salivary flow. Recovery can be seen with time; however, long-term prospective data are lacking. The objective of this study was to analyze the long-term parotid gland function after irradiation for head-and-neck cancer. METHODS AND MATERIALS: A total of 52 patients with head-and-neck cancer and treated with radiotherapy (RT) were prospectively evaluated. Stimulated bilateral parotid salivary flow rates were measured before RT and 6 weeks, 6 months, 12 months, and at least 3.5 years after RT completion. A complication was defined as a stimulated parotid flow rate of <25% of the pre-RT flow rate. The normal tissue complication probability model proposed by Lyman was fit to the data. Multilevel techniques were used to model the patterns of flow rates with time. RESULTS: The mean stimulated flow rate of the parotid glands before RT was 0.31 mL/min (standard deviation [SD], 0.21). This was reduced to 0.14 mL/min (SD, 0.15) at 6 weeks after RT and recovered to 0.20 mL/min (SD, 0.22) at 6 months and 0.19 mL/min (SD, 0.21) at 12 months after RT. The mean stimulated flow rate was 0.25 mL/min (SD, 0.28) 5 years after RT. The mean dose to the parotid gland resulting in a 50% complication probability increased from 34 Gy at 6 weeks to 40 Gy at 6 months, 42 Gy at 12 months, and 46 Gy at 5 years after RT. Multilevel modeling indicated that both dose and time were significantly associated with the flow ratio. CONCLUSION: Salivary output can still recover many years after RT. At 5 years after RT, we found an increase in the salivary flow rate of approximately 32% compared with at 12 months after RT.
PURPOSE: Irradiation of the parotid glands causes salivary dysfunction, resulting in reduced salivary flow. Recovery can be seen with time; however, long-term prospective data are lacking. The objective of this study was to analyze the long-term parotid gland function after irradiation for head-and-neck cancer. METHODS AND MATERIALS: A total of 52 patients with head-and-neck cancer and treated with radiotherapy (RT) were prospectively evaluated. Stimulated bilateral parotid salivary flow rates were measured before RT and 6 weeks, 6 months, 12 months, and at least 3.5 years after RT completion. A complication was defined as a stimulated parotid flow rate of <25% of the pre-RT flow rate. The normal tissue complication probability model proposed by Lyman was fit to the data. Multilevel techniques were used to model the patterns of flow rates with time. RESULTS: The mean stimulated flow rate of the parotid glands before RT was 0.31 mL/min (standard deviation [SD], 0.21). This was reduced to 0.14 mL/min (SD, 0.15) at 6 weeks after RT and recovered to 0.20 mL/min (SD, 0.22) at 6 months and 0.19 mL/min (SD, 0.21) at 12 months after RT. The mean stimulated flow rate was 0.25 mL/min (SD, 0.28) 5 years after RT. The mean dose to the parotid gland resulting in a 50% complication probability increased from 34 Gy at 6 weeks to 40 Gy at 6 months, 42 Gy at 12 months, and 46 Gy at 5 years after RT. Multilevel modeling indicated that both dose and time were significantly associated with the flow ratio. CONCLUSION: Salivary output can still recover many years after RT. At 5 years after RT, we found an increase in the salivary flow rate of approximately 32% compared with at 12 months after RT.
Authors: Valerio Nardone; Paolo Tini; Christophe Nioche; Maria Antonietta Mazzei; Tommaso Carfagno; Giuseppe Battaglia; Pierpaolo Pastina; Roberta Grassi; Lucio Sebaste; Luigi Pirtoli Journal: Radiol Med Date: 2018-01-24 Impact factor: 3.469
Authors: Peter van Luijk; Sarah Pringle; Joseph O Deasy; Vitali V Moiseenko; Hette Faber; Allan Hovan; Mirjam Baanstra; Hans P van der Laan; Roel G J Kierkels; Arjen van der Schaaf; Max J Witjes; Jacobus M Schippers; Sytze Brandenburg; Johannes A Langendijk; Jonn Wu; Robert P Coppes Journal: Sci Transl Med Date: 2015-09-16 Impact factor: 17.956
Authors: Luciana Lastrucci; Silvia Bertocci; Vittorio Bini; Simona Borghesi; Roberta De Majo; Andrea Rampini; Pietro Giovanni Gennari; Paola Pernici Journal: Radiol Med Date: 2017-08-31 Impact factor: 3.469
Authors: Molly M McCulloch; Choonik Lee; Benjamin S Rosen; Justin D Kamp; Chrissy M Lockhart; Jae Y Lee; Daniel F Polan; Peter G Hawkins; Carlos J R Anderson; Jolien Heukelom; Jan-Jakob Sonke; Clifton D Fuller; James M Balter; Randall K Ten Haken; Avraham Eisbruch; Kristy K Brock Journal: Pract Radiat Oncol Date: 2019-03-02