Head and Neck Cancer

PV QA 2 - Poster Viewing Q&A 2

MO_25_2590 - Outcomes of Patients With Connective Tissue Diseases Receiving Radical Radiation Therapy for Nasopharyngeal Carcinoma in the IMRT Era - A Matched Cohort Analysis

Monday, October 22
10:45 AM - 12:15 PM
Location: Innovation Hub, Exhibit Hall 3

Outcomes of Patients With Connective Tissue Diseases Receiving Radical Radiation Therapy for Nasopharyngeal Carcinoma in the IMRT Era - A Matched Cohort Analysis
K. W. A. Cheung, P. C. Chan, W. Y. A. Ng, and C. S. F. Wong; Department of Clinical Oncology, Tuen Mun Hospital, Hong Kong, Hong Kong

Purpose/Objective(s): Connective tissue diseases (CTD) have historically been considered to be associated with a greater risk of severe RT-related acute and late toxicities. To date, limited studies focusing on patients with CTD receiving head and neck RT have reported a risk of severe complications. As RT is critical to the management of NPC, we sought to determine the risk of acute and late RT complications in a large cohort of NPC patients.

Materials/Methods: Patients with a diagnosis of CTD having undergone radical RT (intensity-modulated radiotherapy or volumetric modulated arc therapy) for NPC between 2004 and 2016 were retrospectively reviewed. Control patients were matched 2:1 with CTD group based on age, histology, AJCC (7th edition) TNM stages, and the treatments received. RT-related acute and late toxicities (CTCAE v4.03) were the primary outcomes; 3-year survival rates were the secondary outcomes.

Results: Of the 1297 patients treated for NPC during the review period, 19 (mean [range] age, 54.7 [35-69] years; 11 [57.9%] men) had CTD. All had undifferentiated carcinoma, and were irradiated to a total dose of 66-70Gy, given in 33 fractions over 6.5-7 weeks. As for disease stage, 10.5% had stage I, 26.3% stage II, 36.8% stage III, 21.1% stage IVA, and 5.3% stage IVB. The commonest CTD were malignancy-related dermatomyositis (n=8, 42.1%), rheumatoid arthritis (n=5, 26.3%) and systemic sclerosis (n=2, 10.5%). Median follow-up was 38.2 months (IQR 13.5-59.8). Frequencies of grade 3 mucositis and dermatitis were both 5.3% in CTD group, vs 2.6% (P=1.00) and 0% (P=0.33) respectively in control group. Grade 3 dysphagia was evident in 4 CTD patients during RT (21.1%, vs 7.9% in control group, P=0.21), while tube feeding was indicated in 5 (26.3%, vs 7.9% in control group, P=0.10); notably, 3 of them (all had dermatomyositis) already presented with dysphagia upon diagnosis. Upon follow-up, grade 3 dysphagia occurred in 10.5% in CTD group and 2.6% in control group (P=0.26), while grade 3 hearing impairment in 10.5% in both groups. There were no grade 4 acute or late toxicities. Three-year local failure-free survival, regional failure-free survival, distant failure-free survival and disease-free survival in CTD group vs control group were 100.0% vs 86.6% (P=0.22), 86.9% vs 85.7% (P=0.79), 77.7% vs 88.3% (P=0.33) and 77.7% vs 73.2% (P=0.93) respectively. There was statistically significant difference in 3-year overall survival (OS) between CTD and control groups: 68.9% and 93.8% (P=0.02), while 3-year cancer-specific survival (CSS) was similar (80.0% vs 93.8%, P=0.50). In CTD group, 8 patients succumbed, 5 of them died of causes unrelated to NPC or RT complications.

Conclusion: Our data do not suggest an increased risk of severe acute and late toxicities in CTD patients receiving radical RT for NPC, while achieving comparable disease control and CSS. However, OS was significantly poorer in patients with CTD than the matched cohort.

Author Disclosure: K. Cheung: None. P. Chan: None. W. Ng: None.

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