Does radiation dose to the salivary glands and oral cavity predict patient-rated xerostomia and sticky saliva in head and neck cancer patients treated with curative radiotherapy?
OBJECTIVE
To investigate the association between the mean salivary gland and oral cavity dose, with patient-rated moderate and severe xerostomia and sticky saliva.


METHODS
One hundred and fifty-seven patients treated with bilateral irradiation for head and neck cancer were included. The parotid and submandibular glands and the oral cavity were delineated on plannings-CT scans. At baseline and 6 and 12 months self-reported xerostomia and sticky saliva were assessed using the EORTC QLQ-H&N35 questionnaire.


RESULTS
At 6 months a significant association between the mean parotid (MD(par)) and mean submandibular dose (MD(subm)) and xerostomia was observed (OR - MD(par): 1.17; P=0.002 and OR - MD(subm): 1.08; P = 0.02). Between MD(par) and MD(subm), a significant interaction term was present. No significant association was found with the oral cavity dose. Xerostomia was reversible depending on MD(par) and MD(subm). Considering Sticky saliva, a significant association was found at 6 and 12 months with MD(subm) (OR: 1.03; P < 0.001). The P50 for sticky saliva increased with elapsing time.


CONCLUSIONS
Both MD(par) and MD(subm) influence the risk of xerostomia in irradiated patients at 6 months. This probability as a function of the mean parotid dose significantly depended on the mean dose in the submandibular glands. Sticky saliva mainly depends on MD(subm).
Jellema
Anke Petra
AP
Department of Radiation Oncology, VU University Medical Center, Amsterdam, The Netherlands. ap.jellema@vumc.nl
Doornaert
Patricia
P
Slotman
Ben J
BJ
Leemans
C Rene
CR
Langendijk
Johannes A
JA
D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D016001:Confidence Intervals; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006258:Head and Neck Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009055:Mouth / Q000528:radiation effects; D015995:Prevalence; D011336:Probability; D011446:Prospective Studies; D011832:Radiation Injuries / Q000453:epidemiology; D011879:Radiotherapy Dosage; D018714:Radiotherapy, Adjuvant; D011882:Radiotherapy, High-Energy / Q000009:adverse effects* / Q000379:methods; D018570:Risk Assessment; D012463:Saliva; D012469:Salivary Glands / Q000528:radiation effects*; D012472:Salivation / Q000528:radiation effects; D015996:Survival Rate; D016896:Treatment Outcome; D014987:Xerostomia / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology