ABSTRACT
BACKGROUND: Intensity modulated proton beam therapy (IMPT) for head and neck cancer offers dosimetric benefits for the organs at risk when compared to photon-based volumetric modulated arch therapy (VMAT). However, limited data exists about the potential benefits of IMPT for tooth-bearing regions. The aim of this study was to compare the IMPT and VMAT radiation dosimetrics of the tooth-bearing regions in head and neck cancer patients. Also, we aimed to identify prognostic factors for a cumulative radiation dose of ≥40 Gy on the tooth-bearing areas, which is considered the threshold dose for prophylactic dental extractions. METHODS: A total of 121 head and neck cancer patients were included in this retrospective analysis of prospectively collected data. We compared the average Dmean values of IMPT versus VMAT of multiple tooth-bearing regions in the same patients. Multivariate logistic regression analysis was performed for receiving a cumulative radiation dose of ≥40 Gy to the tooth-bearing regions (primary endpoint) in both VMAT and IMPT. RESULTS: A lower Dmean was seen after applying IMPT to the tooth-bearing tumour regions (p < 0.001). Regarding VMAT, oral cavity tumours, T3-T4 tumours, molar regions in the mandible, and regions ipsilateral to the tumour were risk factors for receiving a cumulative radiation dose of ≥40 Gy. CONCLUSIONS: IMPT significantly reduces the radiation dose to the tooth-bearing regions.
Subject(s)
Head and Neck Neoplasms , Proton Therapy , Radiotherapy, Intensity-Modulated , Humans , Proton Therapy/adverse effects , Retrospective Studies , Radiotherapy Dosage , Radiotherapy, Intensity-Modulated/adverse effects , Head and Neck Neoplasms/radiotherapy , Radiotherapy Planning, Computer-AssistedABSTRACT
AIM OF THE STUDY: This study investigated the incidence of hyperfibrinolysis upon emergency department (ED) admission in patients with out of hospital cardiac arrest (OHCA), and the association of the degree of hyperfibrinolysis with markers of hypoperfusion. METHODS: From 30 OHCA patients, cardiopulmonary resuscitation (CPR) time, pH, base excess (BE), and serum lactate were measured upon ED admission. A 20% decrease of rotational thromboelastometry maximum clot firmness (MCF) was defined as hyperfibrinolysis. Lysis parameters included maximum lysis (ML), lysis onset time (LOT) and lysis index at 30 and 45 min (LI30/LI45). The study was approved by the Human Subjects Committee. RESULTS: Hyperfibrinolysis was present in 53% of patients. Patients with hyperfibrinolysis had longer median CPR times (36 (15-55) vs. 10 (7-18)min; P=0.001), a prolonged activated partial thromboplastin time (54 ± 16 vs. 38 ± 10s; P=0.006) and elevated D-dimers (6.1 ± 2.1 vs. 2.3 ± 2.0 µg/ml; P=0.02) when compared to patients without hyperfibrinolysis. Hypoperfusion markers, including pH (6.96 ± 0.11 vs. 7.17 ± 0.15; P<0.001), base excess (-20.01 ± 3.53 vs. -11.91 ± 6.44; P<0.001) and lactate (13.1 ± 3.7 vs. 8.0 ± 3.7 mmol/l) were more disturbed in patients with hyperfibrinolysis than in non-hyperfibrinolytic subjects, respectively. The LOT showed a good association with CPR time (r=-0.76; P=0.003) and lactate (r=-0.68; P=0.01), and was longer in survivors (3222 ± 34s) than in non-survivors (1,356 ± 833; P=0.044). CONCLUSION: A substantial part of OHCA patients develop hyperfibrinolysis in association with markers for hypoperfusion. Our data further suggest that the time to the onset of clot lysis may be an important marker for the severity of hyperfibrinolysis and patient outcome.