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Y.N. Kang



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    P1.08 - Poster Session 1 - Radiotherapy (ID 195)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Radiation Oncology + Radiotherapy
    • Presentations: 1
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      P1.08-015 - Comparision of Once-daily vs Twice-daily Thoracic Radiotherapy Outcomes in Limited Disease Small Cell Lung Cancer Treated Concurrently With Cisplatin and Etoposide : A Single Institution Retrospective Analysis (ID 1794)

      09:30 - 09:30  |  Author(s): Y.N. Kang

      • Abstract

      Background
      To evaluate and compare outcomes of two fractionation scheme of thoracic radiotherapy(once-daily vs twice daily), concurrently with cisplatin and etoposide(EP) in limited disease small cell lung cancer(LD-SCLC).

      Methods
      LD-SCLC patients treated with definitive chemoradiotherapy at Seoul St. Mary’s Hospital were reviewed. Total 51 patients received radiotherapy concurrently with EP, after initially starting 1~2 cycle of EP. Once-daily group (33 patients) irradiated total 50~56 Gy in 28~32 fractions, and twice-daily group (18 patients) irradiated 45 Gy in 30 fractions. Subsquently, additional 1~2 cycles of EP was given. After CRT, 38 patients who get remission in thorax, received prophylactic cranial irradiation(PCI). PCI consisted of total 24~30 Gy over a 2-weeks period.

      Results
      Median follow-up duration is 47.5 months. 2-year overall survival(OS) rate of all patient was 61.2 % (median 27.4 months). 2-year OS rate was higher (83.9%) in once-daily group, compared with twice-daily group (53.1%), but there were no statistically significant difference (p=0.071). After CRT, 47 patients (93%) had partial to complete remission, but 30 patients were eventually progressed or recurred. Main failure pattern was distant failure (46.7%). The trend of higher loco-regional failure (50%) was detected in twice-daily group compared with once-daily group (30%), but there was no statistically difference between two groups (p=0.055). 7 brain metastasis were detected in once-daily group and 2 in twice-daily group, but there was no statistically difference between two groups (p=0.184). In subgroup analysis of 38 PCI patients, brain metastasis rate were not statistically differ from two groups (once-daily; p=0.171, twice-daily; p=0.146). There were also no significant differences of 2-year progression free survival(PFS), loco-regional disease free survival(LRDFS) and distant metastasis free survival(DMFS) between groups(PFS; p=0.541, LRDFS; p=0.238, DMFS; p=0.792), and no statistically differences in acute toxicities(non-hematologic p=0.128, hematologic p=0.277).

      Conclusion
      Our results showed no statistically significant differences between two groups, although showing relatively higher OS rate and lower brain metastasis in twice-daily group favoring twice-daily radiation scheme and the trend of higher loco-regional failure in twice-daily group. It could be clues for considering thoracic radiation dose escalation above 45 Gy in twice-daily scheme to lower loco-regional failure. Small patients number and short follow up duration of twice-daily group could be the factor and limitation of the results causing these low statistical power. Further long term evaluation and analysis of comparing two groups could be important in that points.

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    P3.08 - Poster Session 3 - Radiotherapy (ID 199)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Radiation Oncology + Radiotherapy
    • Presentations: 1
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      P3.08-004 - Significance of low dose distribution in developing radiation pneumonitis after helical tomotherapy based hypofractionated radiotherapy for pulmonary metastases (ID 936)

      09:30 - 09:30  |  Author(s): Y.N. Kang

      • Abstract

      Background
      Hypofractionated radiotherapy (HRT) for pulmonary malignancies has been now commonly used, as a tumorcidal dose can be accurately delivered to the target without any consequential dose to adjacent normal tissues. However, radiation pneumonitis (RP) is still a major problem after HRT. To determine the significant parameters in developing RP, we retrospectively investigated data from patients treated with HRT using helical tomotherapy for lung metastases.

      Methods
      A total of 45 patients were included in the study and the median age was 53 years old. The median prescriptive doses were 50 Gy to internal target volume and 40 Gy to planning target volume in 10 fractions over 2 weeks. RP was diagnosed by chest X-ray or computed tomography after HRT and its severity was determined by CTCAE version 4.0.

      Results
      The incidence of symptomatic RP was 26.6%. Univariate analysis showed that mean lung doses, V5, V10, V15, V20 and V25 were statistically significant in developing symptomatic RP (P<0.05). However, only V5 was statistically significant in developing symptomatic RP in multivariate analysis (p=0.019). In the ROC curve, V5 was the most powerful predictor of symptomatic RP, and its AUC was 0.780 (p=0.004). In addition, the threshold value of V5 to develop symptomatic RP was 65%. The large distribution of a low dose resulted in a higher risk of lung toxicity.

      Conclusion
      To prevent symptomatic RP, we should limit the V5 to less than 65%, in addition to considering conventional dosimetric factors. However, a further clinical study must be done in oreder to confirm this result.