3.3 Prognostic factors
Univariate analysis suggested that sex (P=0.037) and frequency of previous EBRT (P=0.001) were prognostic factors influencing LC (Table 3). Moreover, univariate analysis also suggested that frequency of previous EBRT (P=0.012) was prognostic factors influencing OS (Table 4).
For patients who had received only once EBRT, the mean duration of LC was 47.9 (range 5.1-60.2) months. LC at 1, 3 and 5 years was 93.8%, 58.6% and 58.6%, respectively. The median OS was 31.6 (range, 5.1~60.2, average 34.3) months. OS at 1-, 3- and 5-years was 72.3%, 36.3% and 18.1%, respectively. For those who had received EBRT twice or three times, the mean duration of LC was 20.8 (range 2.1-52.2) months. LC at 1, 3 and 5 years was 42.4%, 25.5% and 0%, respectively. The median OS was 9.2 (range, 2.1~33.4, average 13.9) months. OS at 1- and 3-years was 31.2% and 0%, respectively (Figure 4).
The use of 3D-PT might improve LC (P=0.078) though the statistically difference was less significant. For patients who used 3D-PT, the mean duration of LC was 39.1 (range 2.1-41.9) months. LC at 1 and 3 years was 92.9% and 92.9%, respectively. For those who did not use 3D-PT, the mean duration of LC was 29.2 (range 2.1-60.2) months. LC at 1 and 2 years was 61.5% and 29.5%, respectively.