Nishimura Y, Nagata Y, Okajima K, Mitsumori M, Hiraoka M, Masunaga S, Ono K, Shoji K, Kojima H
Department of Radiology, Faculty of Medicine, Kyoto University, Japan.
Radiother Oncol. 1996 Sep;40(3):225-32. doi: 10.1016/0167-8140(96)01796-3.
Local control probabilities of T1,2 glottic laryngeal cancer were evaluated in relation to dose and fractionation of radiation therapy (RT).
Between 1975 and 1993, 96 T1N0M0 glottic cancers and 32 T2N0M0 glottic cancers were treated with definitive RT. Total RT dose was 60-66 Gy/2 Gy for most of the T1 and T2 tumors, although 10 T2 tumors were treated with hyperfractionation (72-74.4 Gy/1.2 Gy bid). Of the 128 patients, 90 T1 glottic tumors and 30 T2 glottic tumors were followed for > 2 years after treatment. Multivariate analyses using the Cox proportional hazards model and a logistic regression analysis were performed to evaluate the significance of prognostic variables on local control.
The 5-year local control probability for T1 tumors was 85%, whereas that for T2 tumors was 71%. Multivariate analyses demonstrated that only overall treatment time (OTT) was a significant variable for local control. Total RT dose, normalized total doses at a fraction size of 2 Gy, and fraction size were not significant. Local control probability of T1 tumors with an OTT of 42-49 days was significantly higher than that of tumors with an OTT of > 49 days (P < 0.02). Only a 1-week interruption of RT, due to holidays, significantly reduced the 5-year local control probability of T1 glottic tumors from 89 to 74% (P < 0.05).
These results indicate that OTT is a significant prognostic factor for local control of T1 glottic tumors.
评估T1、T2期声门型喉癌的局部控制概率与放射治疗（RT）剂量及分割方式的关系。
1975年至1993年间，对96例T1N0M0声门型癌和32例T2N0M0声门型癌进行了根治性放疗。大多数T1和T2肿瘤的总放疗剂量为60 - 66 Gy/2 Gy，不过有10例T2肿瘤采用了超分割放疗（72 - 74.4 Gy/1.2 Gy，每日两次）。128例患者中，90例T1声门型肿瘤和30例T2声门型肿瘤在治疗后随访超过2年。采用Cox比例风险模型和逻辑回归分析进行多因素分析，以评估预后变量对局部控制的意义。
T1肿瘤的5年局部控制概率为85%，而T2肿瘤为71%。多因素分析表明，仅总治疗时间（OTT）是局部控制的显著变量。总放疗剂量、2 Gy分割剂量下的归一化总剂量以及分割剂量均无显著意义。OTT为42 - 49天的T1肿瘤局部控制概率显著高于OTT > 49天的肿瘤（P < 0.02）。仅因节假日导致放疗中断1周，就显著降低了T1声门型肿瘤的5年局部控制概率，从89%降至74%（P < 0.05）。
这些结果表明，OTT是T1声门型肿瘤局部控制的重要预后因素。
