Comorbidity in patients with head and neck cancer can influence therapeutic decision-making. Prospective longitudinal rigorous collection of comorbidity data is warranted for correlation with outcomes. ACE-27 may be a clinically more meaningful tool for comorbidity assessment.

PurposeTo estimate dose–response relationship using dynamic quantitative 99mTc-pertechnate scintigraphy in head-neck cancer patients treated with parotid-sparing conformal radiotherapy.MethodsDynamic quantitative pertechnate salivary scintigraphy was performed pre-treatment and subsequently periodically after definitive radiotherapy. Reduction in salivary function following radiotherapy was quantified by salivary excretion fraction (SEF) ratios. Dose–response curves were modeled using standardized methodology to calculate tolerance dose 50 (TD50) for parotid glands.ResultsSalivary gland function was significantly affected by radiotherapy with maximal decrease in SEF ratios at 3-months, with moderate functional recovery over time. There was significant inverse correlation between SEF ratios and mean parotid doses at 3-months (r = −0.589, p < 0.001); 12-months (r = −0.554, p < 0.001); 24-months (r = −0.371, p = 0.002); and 36-months (r = −0.350, p = 0.005) respectively. Using a post-treatment SEF ratio <45% as the scintigraphic criteria to define severe salivary toxicity, the estimated TD50 value with its 95% confidence interval (95% CI) for the parotid gland was 35.1Gy (23.6-42.6Gy), 41.3Gy (34.6-48.8Gy), 55.9Gy (47.4-70.0Gy) and 64.3Gy (55.8-70.0Gy) at 3, 12, 24, and 36-months respectively.ConclusionsThere is consistent decline in parotid function even after conformal radiotherapy with moderate recovery over time. Dynamic quantitative pertechnate scintigraphy is a simple, reproducible, and minimally invasive test of major salivary gland function.Electronic supplementary materialThe online version of this article (doi:10.1186/s13014-015-0371-2) contains supplementary material, which is available to authorized users.

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Definitive CTRT, sequence being individualized depending on performance status and disease stage at presentation, is a feasible and effective treatment modality for locally advanced NSCLC patients in the developing world. Response to treatment is an important prognostic factor for treatment outcomes.