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W. De Wever
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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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P2.03-023 - In-Field Nodal Relapse after Irradiation for Locally Advanced Non-Small-Cell Lung Cancer: Is There a Dose-Effect Relationship? (ID 3201)
09:30 - 09:30 | Author(s): W. De Wever
- Abstract
Background:
We investigated whether prescribed radiation dose is related to in-field nodal relapse. Since in-field nodal relapse is rare according to current literature, the influence of radiation dose on the incidence could be questioned.
Methods:
A retrospective analysis of prospective data was performed. Pathologic lymph nodes were registered based on RECIST 1.1 criteria. An in-field nodal relapse is defined as an increase of at least 20% of the short axis diameter and a minimum absolute increase of 2 mm, taking as reference the short axis diameter measured 3 months (+/-2 months) after radiation therapy. Three subgroups were defined based on EQD2,T (group A: EQD2,T < 50 Gy, group B: EQD2,T 50-55 Gy, group C: EQD2,T > 55 Gy). An actuarial Kaplan-Meier analysis was performed to evaluate the cumulative proportion of in-field nodal relapse per subgroup. A Cox proportional hazards regression analysis was performed to take initial nodal diameter into account.
Results:
A total of 75 patients were reviewed. Sixty-two patients (83%) had stadium IIIA/IIIB disease. Twelve patients (16%) had stadium IV NSCLC who were treated with a radical oligometastatic approach. One patient (1%) had stadium IIB disease. Sixteen patients (21%) were treated with radiotherapy alone (38% group A, 25% group B, 38% group C). Sequential chemoradiotherapy was given in 47 patients (63%) (32% group A, 45% group B and 23% group C). Twelve patients (16%) received concurrent chemoradiotherapy (33% group A, 66% group B). Group A consisted of 25 patients (median age: 65 years (range 45-88), median follow-up: 6 months (range 1-54)). Thirty-three patients were included in group B (median age: 59 years (range 45-80), median follow-up: 8 months (range 1-86)). Group C consisted of seventeen patients (median age: 67 years (range 54-83), median follow-up: 9 months (range 2-45)). In all three groups median number of follow-up CT scans is 2 (range of 1-11 for group A and C, range of 1-13 for group B). Any relapse occurred in fifty-eight patients (77,3%). Nineteen patients (33%) had a locoregional failure only. Twenty-two patients (38%) had distant failure only, either by progression of a known metastasis or occurrence of a new distant lesion. Seventeen patients (29%) had a locoregional and distant failure at once. A total of 142 lymph nodes were taken into account (55 (39%) in group A, 52 (37%) in group B and 35 (25%) in group C). The average baseline short axis diameter per group was 16,3 mm, 15,8 mm and 14,6 mm for group A, B and C respectively. An actuarial Kaplan-Meier analysis performed on all lymph nodes (n=142) showed no significant difference between subgroups (p=0,24). A Cox proportional hazards regression analysis didn’t show a significant effect of baseline nodal diameter on in-field nodal relapse (p=0,82).
Conclusion:
Prescribed radiation dose is not related to the occurrence of in-field nodal relapse. There was no relation between initial lymph node diameter and in-field nodal relapse.
