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W. Mao
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MINI 33 - Radiotherapy and Complications (ID 164)
- Event: WCLC 2015
- Type: Mini Oral
- Track: Treatment of Locoregional Disease – NSCLC
- Presentations: 1
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MINI33.07 - A Restrospective Study of Shrinking Field Radiation Therapy in Chemoradiothrapy for Stage III Non-Small Cell Lung Cancer (ID 3195)
18:30 - 20:00 | Author(s): W. Mao
- Abstract
- Presentation
Background:
The study aimed at investigating the feasibility of shrinking field after complete or partial response during Chemoradiothrapy without surgery for stage III non-small cell lung cancer (NSCLC).
Methods:
This retrospective study was carried on 97 consecutive patients with stage III non-small cell lung cancer (NSCLC), who were good responders to cheomoradiation without surgery between September 2009 and November 2014. Computed tomography scans were performed after 40-50 Gy to evaluate the curative effect. Fifty three-dimensional-conformal treatment or intensity-modulated radiation therapy were redelineated to shrink the radiation volume once or twice during conventionally fractionated radiotherapy, leading to a boost of 6-20Gy delieverd to the shrunk PTV. The gross tumor volume (GTV) and planned target volume (PTV) were messured. The acute symptomatic irradiation-induced pneumonia(ASIP) as well as first progression patterns and overall survival were investigated through follow-up.
Results:
Among 97 patients who obtained complete or partial response with median total dose of 60.0 Gy (range, 46.0-70.0 Gy), 50 patients received shrinking field radiation therapy with a median 184.24 cm[3 ](range, 28.1- 449.7cm[3]) reduction of PTV between the first and last plan. The primary GTV and PTV in shrinking field group was greater than that in non-shrinking field group, as well as the 59Gy-greater radiation dose rate(GTV, 116.8 cm[3] vs 102.9 cm[3 ]; PTV, 493.0 cm[3 ]vs 458.0 cm[3]; 59Gy-greater dose rate, 70 % vs 61.7 %). The incidence of ASIP was 20.6%(20/97) for all the population, shrinking field group of 18%(9/50) and non-shrinking field group of 23.4%(11/47). Fifteen patients progressed locoregionlly, 12 distantly and 3 in both patterns in shrinking field group, while 22 locoregionlly, 16 distantly and 3 in both patterns in non-shrinking field group. Four regional-progression located out of PTV in both groups. The locoregion-progression rate and out-PTV rate were not significant difference(60% vs 61%, P=0.934; 63.3% vs 56.1%, p=0.54). As compared with non-shrinking field group, shrinking field had a similar overall survival(median OS, 29 mouths vs 30 mouths, P=0.546), an improved median progression free survival (median PFS, 19 mouths vs 14 mouths, P=0.945) and a lower incidence of acute irradiation-induced pneumonia, but they were all not statistically significant.
Conclusion:
Shrinking field and dose escalation for good responders during chemoradiotherapy seem safe with acceptable toxicity and outPTV relapse, especially for the lung cancer with a bulky mass. More prospective trials are needed to validate these results.
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