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J.A. Bogart
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ORAL 20 - Chemoradiotherapy (ID 124)
- Event: WCLC 2015
- Type: Oral Session
- Track: Treatment of Locoregional Disease – NSCLC
- Presentations: 1
- Moderators:G. Blumenschein, J.Y. Chang
- Coordinates: 9/08/2015, 10:45 - 12:15, 201+203
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ORAL20.06 - Outcomes of Intensity Modulated and 3D-Conformal Radiotherapy for Stage III Non-Small Cell Lung Cancer in NRG Oncology/RTOG 0617 (ID 938)
10:45 - 12:15 | Author(s): J.A. Bogart
- Abstract
Background:
Intensity modulated radiation therapy (IMRT) has the potential to improve target coverage and spare toxicity in locally-advanced non-small cell lung cancer (NSCLC). However, the effect of IMRT on outcomes for NSCLC has not previously been assessed in a large prospective cooperative group clinical trial.
Methods:
A secondary analysis was performed in patients with stage III NSCLC in NRG/RTOG 0617, a randomized phase III comparison of standard-dose (60 Gy) versus high-dose (74 Gy) chemoradiotherapy +/- cetuximab. Radiotherapy (RT) technique was stratified by IMRT and 3D-conformal radiotherapy (3D-CRT). Baseline prognostic and RT dosimetric parameters were compared between IMRT and 3D-CRT after adjusting for RT dose levels and cetuximab use. The prognostic value of RT technique with respect to toxicity and efficacy was assessed through multivariate logistic regression (MVA) and Cox proportional hazards model after controlling for RT dose level, cetuximab use and other factors.
Results:
Of the 482 eligible patients treated with RT, 53% and 47% were treated with 3D-CRT and IMRT, respectively. The IMRT group had more stage IIIB (38.6 vs. 30.3%, P = 0.056), larger PTVs (mean 486 vs. 427 mL, P = 0.005), and larger PTV:lung ratio (mean 0.15 vs. 0.13, P = 0.013). In spite of larger PTV volumes, IMRT was associated with lower lung V20 (P = 0.08), and lower heart doses (V5, V20, V40) than 3D-CRT. In turn, IMRT was associated with a lower rate (3.5 versus 7.9%) of Grade 3+ pneumonitis (P = 0.0653). On MVA, the lung V20 significantly predicted grade 3+ pneumonitis, while the lung V5 and mean lung doses did not. Larger heart V40 was associated with worse OS (HR=1.013, P < 0.001), and the heart V40 was significantly lower in patients treated with IMRT. Patients treated with IMRT were also more likely (37 versus 29%) to receive full doses of consolidative chemotherapy (P = 0.05).
Conclusion:
Although IMRT was used to treat larger and less favorable tumors in RTOG 0617, it was associated with reduced risk of Grade 3+ pneumonitis and higher likelihood of receiving full doses of consolidative chemotherapy. The heart V40, shown to be highly prognostic for survival, can be substantially reduced with IMRT compared to 3D-CRT.
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P2.03 - Poster Session/ Treatment of Locoregional Disease – NSCLC (ID 213)
- Event: WCLC 2015
- Type: Poster
- Track: Treatment of Locoregional Disease – NSCLC
- Presentations: 1
- Moderators:
- Coordinates: 9/08/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
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P2.03-018 - Tolerability of Re-Irradiation for Locally Recurrent Lung Cancer (ID 836)
09:30 - 17:00 | Author(s): J.A. Bogart
- Abstract
Background:
Treatment of locally recurrent of lung cancer in the setting of prior radiotherapy is a therapeutic challenge, particularly when treating with curative intent.
Methods:
Retrospective review of lung cancer patients treated with 2+ courses of modern radiotherapy, which included image guidance (IGRT). Repeat irradiation was defined as an overlap of the gross tumor volume (GTV) in all treatment courses.
Results:
Thirty-three patients, 25 non-small cell and 8 small cell, received re-irradiation including one patient treated thrice. Thirteen patients initially had early disease (6 stage I, 7 II), and 20 patients had locally advanced or advanced disease. Median interval between treatments was 15 months (range 5 months – 13 years 3 months). 16 patients received concurrent chemotherapy with both courses. 13 additional patients received chemotherapy concurrently during one of the courses of treatment. Seven patients were treated with stereotactic body radiation therapy for one of the courses. 24 patients were treated to the mediastinum twice and 9 additional patients received mediastinal treatment during one of the courses. Cumulative prescribed doses ranged up to 14,000 cGy and 18 patients received > 10,000 cGy. Maximum absolute dose to the lung was 14,000 cGy and to the mediastinum was 14,500 cGy. Ten patients remain alive with a median follow up of 20 months (range 9 months – 36 months). Treatment was generally well tolerated with esophagitis <= grade 3 common during the first or second course of therapy (16% and 24% respectively). Fatigue was noted in 18% of patients following the 2[nd] course of radiotherapy and only 3% during the initial course but this may be related to concurrent chemotherapy. One patient developed grade 4 dyspnea possibly related to repeat irradiation, though it was the 5[th] overall course of radiotherapy to the chest. Grade 5 toxicity was not observed and severe late effects were also not reported.
Conclusion:
Re-irradiation, even when concurrent chemotherapy is utilized, appears to be well tolerated with modern treatment planning including the use of IGRT. Further follow-up is necessary to better define local control, overall survival, and potential late toxicity. Additional studies are warranted to further investigate the long-term impact of patients treated more than once to the same region.
