Acute Lymphopenia and Recovery With Prophylactic Pelvic Nodal Radiotherapy in Oligometastatic Prostate Cancer: Interim Results From the Prospective PROLONG2 Cohort.
- 1Department of Radiation Oncology, Peking University First Hospital, Beijing, China.
- 2Department of Urology, Peking University First Hospital, Beijing, China.
Abstract
Background
Prophylactic pelvic nodal radiotherapy (PRT) aims to eradicate occult pelvic nodal disease in oligometastatic prostate cancer but increases lymphocyte exposure. Its early hematologic safety and lymphocyte recovery when added to radiotherapy to the prostate/prostate region and all imaging-visible metastases remain uncertain.Methods
PROLONG2 is an ongoing, single-center, prospective, nonrandomized, two-arm cohort study. This interim analysis included 133 patients who completed radiotherapy: 86 with PRT and 47 without PRT (NPRT). The key safety endpoint was acute grade ≥ 3 lymphopenia. Other assessments included lymphocyte status at 6-12 months and acute hematologic and genitourinary/gastrointestinal toxicities. The association was estimated by multivariable logistic regression adjusted for age, clinical N stage, and hormone-sensitivity status. Survival analysis was exploratory.Results
Acute grade ≥ 3 lymphopenia occurred in 43/86 PRT patients (50.0%) and 8/47 NPRT patients (17.0%). PRT remained associated with acute grade ≥ 3 lymphopenia after adjustment (OR, 4.03; 95% CI, 1.55-11.54; p = 0.006). At 6-12 months, grade ≥ 2 lymphopenia occurred in 18.2% versus 16.7%, and grade ≥ 3 lymphopenia in 1.3% versus 2.4%, respectively. Among evaluable PRT patients with acute grade ≥ 3 lymphopenia, 25/38 (65.8%) recovered to grade 0-1. No acute grade ≥ 3 genitourinary/gastrointestinal toxicity occurred. Progression-free survival data remained immature, with only eight events reported.Conclusions
PRT was associated with markedly more acute lymphopenia, but persistent severe lymphopenia was uncommon and the between-group difference was substantially attenuated at 6-12 months. Continued prospective hematologic surveillance and mature survival data are needed to determine PRT's benefit-risk profile.Trial registration
Chinese Clinical Trial Registry: ChiCTR2400083776.
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BibTeX
@article{qi2026acute,
title = {{Acute Lymphopenia and Recovery With Prophylactic Pelvic Nodal Radiotherapy in Oligometastatic Prostate Cancer: Interim Results From the Prospective PROLONG2 Cohort.}},
author = {Xin Qi and Hewei Wang and Huan Zhang and Xueying Ren and Mingwei Ma and Xiaoying Li and Wanqi Zhang and Zhisong He and Yi Song and Cheng Shen and Wei Yu and Yu Fan and Xianshu Gao and Hongzhen Li},
journal = {Cancer medicine},
year = {2026},
month = nov,
doi = {10.1002/cam4.72466},
url = {https://europepmc.org/article/MED/42972866},
note = {CC BY-NC},
}
RIS
TY - JOUR
TI - Acute Lymphopenia and Recovery With Prophylactic Pelvic Nodal Radiotherapy in Oligometastatic Prostate Cancer: Interim Results From the Prospective PROLONG2 Cohort.
AU - Xin Qi
AU - Hewei Wang
AU - Huan Zhang
AU - Xueying Ren
AU - Mingwei Ma
AU - Xiaoying Li
AU - Wanqi Zhang
AU - Zhisong He
AU - Yi Song
AU - Cheng Shen
AU - Wei Yu
AU - Yu Fan
AU - Xianshu Gao
AU - Hongzhen Li
PY - 2026
DA - 2026/11/01
JO - Cancer medicine
DO - 10.1002/cam4.72466
UR - https://europepmc.org/article/MED/42972866
AB - Background Prophylactic pelvic nodal radiotherapy (PRT) aims to eradicate occult pelvic nodal disease in oligometastatic prostate cancer but increases lymphocyte exposure. Its early hematologic safety and lymphocyte recovery when added to radiotherapy to the prostate/prostate region and all imaging-visible metastases remain uncertain.Methods PROLONG2 is an ongoing, single-center, prospective, nonrandomized, two-arm cohort study. This interim analysis included 133 patients who completed radiotherapy: 86 with PRT and 47 without PRT (NPRT). The key safety endpoint was acute grade ≥ 3 lymphopenia. Other assessments included lymphocyte status at 6-12 months and acute hematologic and genitourinary/gastrointestinal toxicities. The association was estimated by multivariable logistic regression adjusted for age, clinical N stage, and hormone-sensitivity status. Survival analysis was exploratory.Results Acute grade ≥ 3 lymphopenia occurred in 43/86 PRT patients (50.0%) and 8/47 NPRT patients (17.0%). PRT remained associated with acute grade ≥ 3 lymphopenia after adjustment (OR, 4.03; 95% CI, 1.55-11.54; p = 0.006). At 6-12 months, grade ≥ 2 lymphopenia occurred in 18.2% versus 16.7%, and grade ≥ 3 lymphopenia in 1.3% versus 2.4%, respectively. Among evaluable PRT patients with acute grade ≥ 3 lymphopenia, 25/38 (65.8%) recovered to grade 0-1. No acute grade ≥ 3 genitourinary/gastrointestinal toxicity occurred. Progression-free survival data remained immature, with only eight events reported.Conclusions PRT was associated with markedly more acute lymphopenia, but persistent severe lymphopenia was uncommon and the between-group difference was substantially attenuated at 6-12 months. Continued prospective hematologic surveillance and mature survival data are needed to determine PRT's benefit-risk profile.Trial registration Chinese Clinical Trial Registry: ChiCTR2400083776.
SN - 2045-7634
ER -