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Durability of the parotid‐sparing effect of intensity‐modulated radiotherapy ( IMRT ) in early stage nasopharyngeal carcinoma: A 15‐year follow‐up of a randomized prospective study of IMRT versus two‐dimensional radiotherapy
Author(s) -
Poon Darren M. C.,
Kam Michael K. M.,
Johnson David,
Mo Frankie,
Tong Macy,
Chan Anthony T. C.
Publication year - 2021
Publication title -
head and neck
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.012
H-Index - 127
eISSN - 1097-0347
pISSN - 1043-3074
DOI - 10.1002/hed.26634
Subject(s) - medicine , nasopharyngeal carcinoma , radiation therapy , prospective cohort study , stage (stratigraphy) , randomized controlled trial , oncology , surgery , paleontology , biology
Background The durability of improved xerostomia with intensity‐modulated radiotherapy (IMRT) in patients with early stage nasopharyngeal carcinoma (NPC) is uncertain. We conducted a long‐term prospective assessment of participants treated with IMRT or two‐dimensional radiotherapy (2DRT) in a prior randomized study. Methods Parent study participants (IMRT, n = 28; 2DRT, n = 28) who were free of second malignancy or recurrence were eligible. Long‐term radiotherapy‐related toxicities were graded according to the Radiation Therapy Oncology Group (RTOG) criteria. Long‐term patient‐reported outcomes were assessed by the six‐item xerostomia (XQ) and two European Organisation for Research and Treatment of Cancer (EORTC) questionnaires (QLQ‐C30, QLQ‐H&N35). Overall survival (OS), locoregional relapse‐free survival (LRFS), distant relapse‐free survival (DRFS), and the rate of symptomatic late complications (SLCs) were estimated for the entire cohort ( n = 56). Results Totally, 21 (IMRT, n = 10; 2DRT, n = 11) patients gave consent and were assessed for an overall median follow‐up of 15.5 years. There was significantly less RTOG ≥grade 2 xerostomia with IMRT versus 2DRT (20% vs. 90%; p = 0.001), but no significant difference in XQ scores. Patients in the IMRT arm reported lower mean scores for the “dry mouth” domain of EORTC QLQ‐H&N35 ( p = 0.02) and showed trends toward better 15‐year OS (81.5% vs. 53.8%, p = 0.06), LRFS (70.6% vs. 53.8%, p = 0.38), and DRFS (81.5% vs. 53.8%, p = 0.07). SLCs were more frequent in the 2DRT arm. Conclusions The parotid‐sparing effect of IMRT in NPC treatment is durable, with significantly less physician‐ and patient‐scored xerostomia at 15 years. IMRT results in better long‐term survival and fewer SLCs.