Absolute Lymphocyte Count Nadir During Chemoradiation as a Prognostic Indicator of Esophageal Cancer Survival Outcomes

Dosimetric Effect of Thymus and Thoracic Duct on Radiation-Induced Lymphopenia in Patients With Primary Lung Cancer Who Received Thoracic Radiation

“…Interestingly, most dosimetry parameters are significantly associated with DALC from RT, suggesting that radiation damage to the immune system is not limited to blood and lymphatic organs. This finding is consistent with previous studies showing significance in tumor stage, 11 lung volume, 17 gross tumor volume or planning target volume, 12 , 15 , 17 , 20 , 24 radiation dose, 22 radiation fractions, 22 definitive chemoradiotherapy (CRT), 10 , 13 , 15 radiation type (proton beam therapy, intensity modulated RT, or stereotactic body RT), 10 , 11 , 12 , 13 , 32 , 33 MBD, 10 , 11 and concurrent chemotherapy. 13 …”

“…Although the optimal cutoff for defining lymphopenia is unknown, the majority of studies use a cutoff of 0.5 × 10 9 /L based on CTCAE, 4 , 5 , 6 , 9 , 12 , 15 , 18 , 22 , 25 , 42 , 43 , 44 whereas some studies use 0.2 × 10 9 /L. 7 , 10 , 13 , 16 , 39 Besides empirically referred cutoff from CTCAE, statistical methods such as ROC curves are also reported to define suitable thresholds. 8 , 45 In the present study, we used a cutoff of 0.5 × 10 9 /L and found that only MBD and ITDV were correlated with severe lymphopenia ( P = .001 and P = .014, respectively).…”

“… 2 It has been observed that radiation-induced lymphopenia (RIL) occurs in 40% to 70% of patients treated with radiation therapy (RT) as a result of the direct damage of irradiation to circulating lymphocytes as they travel across the radiation field. 3 RIL, defined as a decrease in absolute lymphocyte counts (ALC) after RT, is a known adverse prognostic factor in many solid tumors, including high-grade glioma, 4 , 5 , 6 , 7 head and neck cancer, 8 , 9 esophageal cancer, 10 , 11 , 12 , 13 pancreatic cancer, 14 , 15 cervical cancer, 16 non-small cell lung cancer (NSCLC), 17 , 18 , 19 and small cell lung cancer. 20 In particular, lymphopenia is associated with worse treatment response and decreased survival.…”

Lymphopenia and Radiation Dose to Circulating Lymphocytes With Neoadjuvant Chemoradiation in Esophageal Squamous Cell Carcinoma

“…Although lower lymphocyte count predicts worse survival outcomes in other solid tumors, there have been contradicting reports in the literature for esophageal cancer. One study 2 in the United States showed that in patients with stage I to III esophageal cancer (85% adenocarcinoma), the lymphopenia group (defined as lymphocyte <0.5 × 10 9 /L) had a higher risk of death (HR for death, 1.6; P = .027) compared with the nonlymphopenia group. This is supported by another study 23 comparing proton beam therapy with IMRT in 448 patients with stage I-IVA esophageal cancer, which showed improved survival with higher lymphocyte count (HR for survival, 1.551; P = .01 per 1 unit of lymphocyte).…”

“…Because lymphocytes play a major role in exerting antitumor immunity, many clinical studies have demonstrated a correlation between absolute lymphocyte counts and survival. 2 , 3 , 4 …”