Prediction of Locoregional Control in Head and Neck Squamous Cell Carcinoma with Serial CT Perfusion during Radiotherapy

Abstract

BACKGROUND AND PURPOSE:Tumor hypoxia is a known factor of radioresistance in HNSCC. CTP is a noninvasive method of measuring tumor perfusion in vivo. The purpose of our study was to determine serial changes in tumor perfusion in HNSCC during a course of RT by using CTP and to correlate tumor perfusion measurements to LRC.

Usefulness of Pseudocontinuous Arterial Spin-Labeling for the Assessment of Patients with Head and Neck Squamous Cell Carcinoma by Measuring Tumor Blood Flow in the Pretreatment and Early Treatment Period

“…Gandhi et al 16 (after 1 cycle of induction chemotherapy; 3-4 weeks after the treatment start) for the TBF measurement compared with the present study and the study by Truong et al 14 These descriptions of TBF decreases in patients with good treatment responses also showed the same trend as that seen in our present patients with PR. In regard to these findings, we had several hypotheses.…”

“…Truong et al 14 reported that an initial increase in TBF in the early treatment period (2 weeks after the treatment started) in patients undergoing chemoradiotherapy predicted a good treatment result. The results of their report showed the same trend as that seen in the present study in regard to the patients who achieved SD status.…”

“…12,13 Because of the difficulties of repetitive scanning, there have been few studies of the changes in TBF with repetitive scanning over the treatment period, and the number of patients in these reports is quite small, at 10 to Ͻ20 patients. [14][15][16] Thus, the role and potential of TBF measurement during treatment remain unclear. TBF measurement by pseudocontinuous arterial spinlabeling (pCASL), which was introduced for the noninvasive measurement of tissue blood flow without the need for a contrast agent and with no radiation exposure, 17,18 was recently demonstrated to be feasible and applicable for HNSCCs 19 ; pCASL thus has potential for the evaluation of treatment effects in patients with HNSCC without the risks with repetitive scanning of contrast-induced nephropathy during chemotherapy and increased radiation exposure.…”

Radiation-induced CT number changes in GTV and parotid glands during the course of radiation therapy for nasopharyngeal cancer

“…These changes were increased with the number of fractions delivered, thus, were radiation induced. Similar CTN changes were not observed (,3%) in the spinal cords and NSTs, where radiation doses were substantially lower than those in the GTVs and parotid glands (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) Gy vs 75-65 Gy in maximum doses). The observed CTN change was highly patient specific.…”

“…The mechanism behind this CTN change is largely unknown. It has been reported that the pre-treatment tumour blood flow and capillary permeability in patients who achieved locoregional control were significantly higher than in those with treatment failure 24 and that low perfusion of head and neck cancer was associated with higher rates of local failure of RT. 25 Tumours that demonstrated CTN reduction may represent regions of improved oxygenation and sensitivity to radiationinduced damages.…”