Risk of on-treatment lymphopenia is associated with treatment outcome and efficacy of consolidation immunotherapy in patients with non-small cell lung cancer treated with concurrent chemoradiotherapy

• Published in: Radiotherapy and oncology Vol. 189; p. 109934
• Main Authors: Yang, Gowoon, Yoon, Hong In, Lee, Joongyo, Kim, Jihun, Kim, Hojin, Cho, Jaeho, Lee, Chang Geol, Chang, Jee Suk, Cho, Yeona, Kim, Jin Sung, Kim, Kyung Hwan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-12-2023
• Subjects: Carcinoma; Chemoradiotherapy; Immunotherapy; Lymphopenia; Non-Small-Cell Lung; Progression-free survival; Survival; RT; Carcinoma; IMRT; NR; CBC; MHD; HR; NSCL; Chemoradiotherapy; MBD; Immunotherapy; Non-Small-Cell Lung; EDIC; PFS; OR; OS; CI; ROC; IQR; Survival; Lymphopenia; ALC; IRB; RTOG; Progression-free survival; CCRT
• DOI: 10.1016/j.radonc.2023.109934
• EISSN: 1879-0887
• ISSN: 0167-8140

•EDIC and pre-RT ALC were associated with severe lymphopenia during RT, and the combination of these two parameters better predicted radiation-induced lymphopenia than EDIC or pre-RT ALC alone.•The combination of EDIC and pre-RT ALC was significantly associated with survival outcomes.•The combination of EDIC and pre-RT ALC predicted the development of locoregional failure as well as distant failure.•Risk of on-treatment lymphopenia, estimated by the combination of EDIC and baseline ALC, could also predict the efficacy of consolidation immunotherapy.
The ability of the effective dose to immune cells (EDIC) and the pre-radiotherapy (RT) absolute lymphocyte count (ALC) to predict lymphopenia during RT, treatment outcomes, and efficacy of consolidation immunotherapy in patients with locally advanced non-small cell lung cancer was investigated.
Among 517 patients treated with concurrent chemoradiotherapy, EDIC was calculated using the mean doses to the lungs, heart, and total body. The patients were grouped according to high and low EDIC and pre-RT ALC, and the correlations with radiation-induced lymphopenia and survival outcomes were determined.
Altogether, 195 patients (37.7%) received consolidation immunotherapy. The cutoff values of EDIC and pre-RT ALC for predicting severe lymphopenia were 2.89 Gy and 2.03 × 109 cells/L, respectively. The high-risk group was defined as EDIC ≥ 2.89 Gy and pre-RT ALC < 2.03 × 109 cells/L, while the low-risk group as EDIC < 2.89 Gy and pre-RT ALC ≥ 2.03 × 109 cells/L, and the rest of the patients as the intermediate-risk group. The incidences of severe lymphopenia during RT in the high-, intermediate-, and low-risk groups were 90.1%, 77.1%, and 52.3%, respectively (P < 0.001). The risk groups could independently predict both progression-free (P < 0.001) and overall survival (P < 0.001). The high-risk group showed a higher incidence of locoregional and distant recurrence (P < 0.001). Consolidation immunotherapy showed significant survival benefit in the low- and intermediate-risk groups but not in the high-risk group.
The combination of EDIC and pre-RT ALC predicted severe lymphopenia, recurrence, and survival. It may potentially serve as a biomarker for consolidation immunotherapy.