Effects of cervical region Ⅱ and oral target area optimization on salivary gland function and oral mucosal response during radiotherapy for oropharyngeal carcinoma / 肿瘤研究与临床

ABSTRACT

Objective:To observe the effects of cervical region Ⅱ and oral target area optimization on therapeutic efficacy, salivary gland function and oral mucosal response during intensity modulated radiation therapy (IMRT) for oropharyngeal cancer.Methods:A total of 50 patients with oropharyngeal squamous cell carcinoma in Xuzhou Cancer Hospital from January 2012 to May 2017 were collected. According to the random number table, they were divided into normal radiotherapy group (the control group), oral and cervical target area optimization group (the observation group), 25 cases in each group. Both groups were treated with IMRT and platinum-chemotherapy. The control group received bilateral cervical region Ⅱ-Ⅳ lymphatic drainage area irradiation (the positive side of the cervical lymph node included Ⅰ B region), and bilateral cervical region Ⅱ was given a tumor dose of 60 Gy (positive lymph nodes were given intensified irradiation); the observation group was optimized for the target area, and the contralateral cervical region Ⅱ B (the side with no positive lymph node) was given a tumor dose of 50 Gy; the observation group's oral structure was delineated as an organ at risk and the average radiation dose (D mean) was limited to <32 Gy. The differences in radiation dose of parotid gland, acute oral mucosal reaction and long-term xerostomia (6 months after the end of radiotherapy), objective remission rate (ORR), local recurrence rate (LRR), 3-year overall survival (OS) were compared between the two groups. Results:In the control group, the contralateral parotid gland D mean was (29±4) Gy, the proportion of irradiation volume exposed to 34 Gy (V 34) was (48±5)%; in the observation group, contralateral parotid gland D mean was (23±3) Gy, V 34 was (41±5)%, and there are statistically significant differences between the two groups ( t values were 6.14, 4.98, all P < 0.05). In the control group, oral D mean was (35±6) Gy, the proportion of volume exposed to 30 Gy (V 30) was (36±5)%; in the observation group oral D mean was (29±4) Gy, V 30 was (28±4)%, and there were statistically significant differences between the two groups ( t values were 4.11, 5.98, all P < 0.05). The incidence of ≥ grade Ⅱ acute oral mucosal adverse reaction and the duration time of oral mucosal ≥ 2 weeks was 64% (16/25) and 76% (19/25), respectively in the control group, 36% (9/25) and 40% (10/25), respectively in the observation group; and the differences were statistically significant ( χ2 values were 3.92, 6.65; P values were 0.048, 0.009). The incidence of ≥ grade Ⅱ long-term xerostomia reaction was 72% (18/25) and 44% (11/25), respectively in the control group and the observation group, and the difference between the two groups was statistically significant ( χ2 = 4.02, P = 0.044). The ORR, LRR, and 3-year OS rates were 80%, 28%, 48% in the control group, and 76%, 24%, 44% in the observation group. There was no statistically significant difference in the OS between the two groups ( χ2 = 0.04, P = 0.849). Conclusions:Optimization of the target area of the oral and cervical region Ⅱ during IMRT for oropharyngeal carcinoma can improve the function of salivary glands, thereby reducing dry mouth and oral mucosal reactions, improving the quality of life of patients; and it does not affect the efficacy of tumor treatment.