Several problems about the stereotactic body radiation therapy for lung cancer / 国际肿瘤学杂志

As the first treatment of choice for medically inoperable patients with early stage non-small cell lung cancer,it is demonstrated that the therapeutic outcome of stereotactic body radiation therapy (SBRT)is similar to that of surgery,but the data is mainly from nonrandomized controls and retrospective studies.More cases of randomized prospective clinical trials are needed to confirm the conclusions.The biologically effective dose ＞ 100 Gy is associated with improved local control and overall survival,and the small tumor volume is correlated with higher local control rate.

Volumetric modulation arc radiotherapy with flattening filter-free beams compared with conventional beams for nasopharyngeal carcinoma: a feasibility study / 癌症

There is increasing interest in the clinical use of flattening filter-free (FFF) beams. In this study, we aimed to investigate the dosimetric characteristics of volumetric modulated arc radiotherapy (VMAT) with FFF beams for nasopharyngeal carcinoma (NPC). Ten NPC patients were randomly selected to undergo a RapidArc plan with either FFF beams (RA-FFF) or conventional beams (RA-C). The doses to the planning target volumes (PTVs), organs at risk (OARs), and normal tissues were compared. The technical delivery parameters for RapidArc plans were also assessed to compare the characteristics of FFF and conventional beams. Both techniques delivered adequate doses to PTVs. For PTVs, RA-C delivered lower maximum and mean doses and improved conformity and homogeneity compared with RA-FFF. Both techniques provided similar maximum doses to the optic nerves and lenses. For the brain stem, spinal cord, larynx, parotid glands, oral cavity, and skin, RA-FFF showed significant dose increases compared to RA-C. The dose to normal tissue was lower in RA-FFF. The monitor units (MUs) were (536 ± 46) MU for RA-FFF and (501 ±25) MU for RA-C. The treatment duration did not significantly differ between plans. Although both treatment plans could meet clinical needs, RA-C is dosimetrically superior to RA-FFF for NPC radiotherapy.

Individualized chemoradiotherapy for locally advanced nasopharyngeal carcinoma / 国际肿瘤学杂志

Nasopharyngeal carcinoma (NPC) is sensitive to radiotherapy and chemotherapy.Combined chemoradiotherapy improved the survival of the patients with locally advanced NPC.However,a part of these patients did not gain the survival benefit from the combined chemoradiotherapy because of the additional serious adverse reaction.In order to achieve the best therapeutic gain after balancing the benefit and cost,all kinds of influencing factors of individualized chemoradiotherapy including the clinical and biological molecular factors which has a broad developing prospect must also be considered.

Late local-regional recurrence of nasopharyngeal carcinoma after conventional radiotherapy / 中华放射肿瘤学杂志

Objective To investigate the local-regional recurrence of nasopharyngeal carcinoma (NPC) 5 years after conventional radiotherapy and its prognosis.Methods From August 1989 to Decem ber 1999,1384 patients with newly histo-pathologicatly diagnosed NPC were treated with conventional radia tion.350 out of 1277 followed-up patients were diagnosed as local-regional failure.The intervals between completion of radiation and tumor relapse ranged from 6 months to 171 months.There were 62 patients with local-regional recurrence 5 years after the radiotherapy,including 41 in nasopharynx,19 in neck and 2 in na sopharynx and neck simultaneously.Thirty-seven patients with late local-regional recurrence received a sec ond course conventional radiotherapy.Results The median survival time was 44 months(95% CI = 30.4 -57.6) of patients with re-irradiation comparing with 14 months (95% CI = 7.1-20.8) of those without. The 5 year survival rate after re-irradiation was 42%.Conclusions Local-regional recurrence of nasopha ryngeal carcinoma can oeoure 5 years after radiotherapy.Second course converntional radiotherapy possesses good results.

Establishment of a cisplatin-induced human nasopharyngeal carcinoma drug-resistant cell line and its biological characteristics / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To establish a CDDP-resistant cell line from human nasopharyngeal carcinoma and evaluate its biological characteristics.@*METHOD@#By continuously exposing and gradually increasing dose of cisplatin (CDDP), a resistant nasopharyngeal carcinoma cell line (HNE1/CDDP) was established. Drug sensitivity of this cell line was detected by MTT assay; the alterations of its biological characteristics were determined using light microscopy, cell counting and flow cytometry (FCM); its ability of adhesion, migration and invasion were also evaluated.@*RESULT@#HNE1/CDDP cell line was developed after 10 months with stable resistance to cisplatin with the resistance index was 5.83. HNE1/CDDP cell exhibited cross-resistance to many other chemotherapeutic agents (carboplatin, oxaliplatin and etoposide, etc). The morphology of HNE1/CDDP changed; doubling time prolonged; and the cell number of S-phase and G2/M-phase decreased while of G0/G1 phase increased compared with parental cells. The ability of adhesion, migration and invasion had no difference between the parental and the resistant cells.@*CONCLUSION@#HNE1/CDDP cell line shows the typical and stable resistant phenotype and can be used as a research model.

Dose at the optic nerve can be reduced with CT-simulation in treatment planning for nasopharyngeal carcinoma / 中华放射肿瘤学杂志

Objective To compare and evaluate dose at optic structures (eyeballs, optic nerves and chiasma) between conventional and CT simulated treatment planning for nasopharyngeal carcinoma. Methods Thirty three patients with T1 to T4 nasopharyngeal carcinoma underwent simulated spiral CT with picker PQ 5000 and AcQ plan 4.1.1 software system. At first irradiation portals were delinated by the simulation films taken on the conventional X ray simulator using the digital reconstruction (DRR) of the treatment planning system (TPS) supplemented by the patient's CT (or MRI) and clinical findings. Then, the gross tumor volume (GTV),clinical target volume (CTV) and planned target volume (PTV) were delineated on every section of the CT scans. At the same time, the silhouette of the nearby important organs was drawn out ,paying special attention to the backward passage of the retrobulbar optic nerves up to the optic chiasma. The final portals were designed by the 3 dimensional relation between the tumor and its surrounding organs. Then dose distribution was separately calculated by two independent TPSs,with 100% at the target center. Finally,the maximum dose (D max ),average dose (D ave ) and median dose (D med ) of the tumor target area, eye ball,optic nerve and also the length of optic nerve included within the portal of these two technics were compared.Results The dose distribution in nasopharyngeal GTV and CTV were satisfactory both in CT simulated and conventional planning. However, the D max ,D ave and D med all showed significant differences. Those by CT simulated planning were obviously lower than those by conventional planning. CT simulated planning was able to spare more optic nerve by leaving it out of the irradiation portal,thereby,avoiding unwanted radiation.Conclusion CT simulated treatment planning is able to reduce the superfluous radiation to the optic nerve in external irradiation of nasophargngeal carcinoma.