Determination of the repair half-time of human nasopharyngeal carcinoma cell lines CNE1, CNE2, HONE1 and C666-1 / 南方医科大学学报

<p><b>OBJECTIVE</b>To determine the repair half-time (T1/2), a speed parameter of sub-lethal damage repair (SLDR), of human nasopharyngeal carcinoma (NPC) cell lines CNE1, HONE1, C666-1 and CNE2.</p><p><b>METHODS</b>A total radiation dose of 8 Gy divided into 4+4 Gy was delivered to the cell lines at the interval of 0 s, 15 s, 30 s, 1 h, 2 h, 4 h or 6 h. The cell survival fractions were determined using the standard cell clonogenic assay. The curves of the changes in the surviving cell fraction after a total dose of 8 Gy, as a function of the interval between the two doses of 4 Gy, were fitted manually, and the T1/2 of each cell line was calculated according to the curves.</p><p><b>RESULTS</b>The T1/2 of CNE1, HONE1, C666-1 and CNE2 were 18 s, 22 s, 29 s and 27 s, respectively.</p><p><b>CONCLUSION</b>The speed of SLDR of NPC cells is quite rapid, indicating that the fraction delivery time longer than 20 s might decrease the effect of radiotherapy.</p>

Three-dimensional conformal radiotherapy combined with transcatheter arterial chemoembolization for massive primary liver cancer / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the outcomes of patients with unresectable massive primary liver cancer (PLC) receiving three-dimensional conformal radiotherapy (3-DCRT) combined with transcatheter arterial chemoembolization (TACE).</p><p><b>METHODS</b>From January 2001 to December 2004, 84 patients with unresectable massive PLC (tumor size> or =10 cm) received 3-DCRT combined with TACE, including 49 cases in UICC/AJCC T(3) stage and 35 cases in T(4) stages. Lymph node metastasis was found in none of the patients, and portal vein tumor thrombosis (PVTT) was detected in 30 cases. Child-Pugh grade A of liver cirrhosis was present in 64 cases and grade B in 20 cases. The mean value of GTV was 705-/+430 cm(3) (170-2099 cm(3)). Following injections of fluorouracil and hydroxycamptothecine into the target artery of the tumor, the mixture of carboplatin, mitomycin (or pirarubicin) and super-liquefactive iodized oil was injected into the target artery. Gelatin sponge was used to embolize the artery. The procedure was repeated every 1.5-2 months according to the condition of the patients, and each patient received 1-3 such procedures. 3-DCRT was performed in all the patients, who received a total dose of 53.6-/+6.6 Gy (4-6 Gy per fraction at the interval of 48 h), and 3 fractions were given every week.</p><p><b>RESULTS</b>Eight patients died in 3 months after 3-DCRT and were not evaluated. The total response rate (CR+PR) in these patients was 68.9% (51/74). The overall survival rates at 1, 2 and 3 years were 55.4%, 24.7% and 15.4%, respectively. T stage, GTV, PVTT and fraction size had no significant impact on the overall survival. Child-Pugh grade was found to have significant impact on the patients' survival (P=0.035, RR=2.440).</p><p><b>CONCLUSION</b>3-DCRT combined with TACE has definite therapeutic effect on advanced massive PLC, and Child-Pugh grade is an independent prognostic factor in such cases.</p>