The effects of local irradiation on circulating lymphocytes in dogs receiving fractionated radiotherapy

Research output: Contribution to journalArticle

Abstract

Localized radiation therapy can be an effective treatment for cancer but is associated with localized and systemic side effects. Several studies have noted changes in complete blood count (CBC) parameters including decreases in the absolute lymphocyte count (ALC) and increases in the neutrophil:lymphocyte ratio (NLR). These changes could reflect immunosuppression and may contribute to decreased efficacy of immunotherapies used to treat cancer. We hypothesized that dogs would demonstrate decreased ALCs during a course of radiotherapy. A retrospective study was conducted on 203 dogs receiving definitive-intent radiotherapy. Demographic information, CBC values and details of the radiotherapy protocol were collected. The mean lymphocyte count pre-treatment was 1630.68 cells/μL (SD ± 667.56) with a mean NLR of 3.66 (SD ± 4.53). The mean lymphocyte count mid-treatment was 1251.07 cells/μL (SD ± 585.96) and the mean NLR was 6.23 (SD ± 4.99). There was a significant decrease in the mean lymphocyte count by 351.41 lymphocytes/μL (SD ± 592.32) between pre-treatment and mid-treatment (P <.0001), and a corresponding significant increase in the mean NLR of 0.93 (P =.02). Lymphopenia grade increased in 33.5% of dogs and was significant (P =.03). The ALC decrease was not correlated with the volume irradiated (P =.27), but correlated with the irradiated volume:body weight ratio (P =.03). A subset of patients (n = 35) with additional CBCs available beyond the mid-treatment time point demonstrated significant and sustained downward trends in the ALC compared with baseline. Although severe lymphopenia was rare, these decreases, especially if sustained, could impact adjuvant therapy for their cancer.

Original languageEnglish (US)
JournalVeterinary and Comparative Oncology
DOIs
StateAccepted/In press - Jan 1 2019

Fingerprint

lymphocyte count
Lymphocyte Count
radiotherapy
Radiotherapy
lymphocytes
irradiation
Dogs
Lymphocytes
neutrophils
dogs
Neutrophils
Lymphopenia
Blood Cell Count
neoplasms
Therapeutics
pretreatment
Second Primary Neoplasms
immunotherapy
immunosuppression
blood

Keywords

  • canine
  • dog
  • immunosuppression
  • lymphopenia
  • radiation therapy

ASJC Scopus subject areas

  • veterinary(all)

Cite this

@article{780c1be55dea4110bdb5504bbd7daad8,
title = "The effects of local irradiation on circulating lymphocytes in dogs receiving fractionated radiotherapy",
abstract = "Localized radiation therapy can be an effective treatment for cancer but is associated with localized and systemic side effects. Several studies have noted changes in complete blood count (CBC) parameters including decreases in the absolute lymphocyte count (ALC) and increases in the neutrophil:lymphocyte ratio (NLR). These changes could reflect immunosuppression and may contribute to decreased efficacy of immunotherapies used to treat cancer. We hypothesized that dogs would demonstrate decreased ALCs during a course of radiotherapy. A retrospective study was conducted on 203 dogs receiving definitive-intent radiotherapy. Demographic information, CBC values and details of the radiotherapy protocol were collected. The mean lymphocyte count pre-treatment was 1630.68 cells/μL (SD ± 667.56) with a mean NLR of 3.66 (SD ± 4.53). The mean lymphocyte count mid-treatment was 1251.07 cells/μL (SD ± 585.96) and the mean NLR was 6.23 (SD ± 4.99). There was a significant decrease in the mean lymphocyte count by 351.41 lymphocytes/μL (SD ± 592.32) between pre-treatment and mid-treatment (P <.0001), and a corresponding significant increase in the mean NLR of 0.93 (P =.02). Lymphopenia grade increased in 33.5{\%} of dogs and was significant (P =.03). The ALC decrease was not correlated with the volume irradiated (P =.27), but correlated with the irradiated volume:body weight ratio (P =.03). A subset of patients (n = 35) with additional CBCs available beyond the mid-treatment time point demonstrated significant and sustained downward trends in the ALC compared with baseline. Although severe lymphopenia was rare, these decreases, especially if sustained, could impact adjuvant therapy for their cancer.",
keywords = "canine, dog, immunosuppression, lymphopenia, radiation therapy",
author = "Kent, {Michael S} and Shaheen Emami and Rebhun, {Robert B} and Theon, {Alain P} and Hansen, {Katherine S} and Ellen Sparger",
year = "2019",
month = "1",
day = "1",
doi = "10.1111/vco.12531",
language = "English (US)",
journal = "Veterinary and Comparative Oncology",
issn = "1476-5829",
publisher = "Wiley-Blackwell",

}

TY - JOUR

T1 - The effects of local irradiation on circulating lymphocytes in dogs receiving fractionated radiotherapy

AU - Kent, Michael S

AU - Emami, Shaheen

AU - Rebhun, Robert B

AU - Theon, Alain P

AU - Hansen, Katherine S

AU - Sparger, Ellen

PY - 2019/1/1

Y1 - 2019/1/1

N2 - Localized radiation therapy can be an effective treatment for cancer but is associated with localized and systemic side effects. Several studies have noted changes in complete blood count (CBC) parameters including decreases in the absolute lymphocyte count (ALC) and increases in the neutrophil:lymphocyte ratio (NLR). These changes could reflect immunosuppression and may contribute to decreased efficacy of immunotherapies used to treat cancer. We hypothesized that dogs would demonstrate decreased ALCs during a course of radiotherapy. A retrospective study was conducted on 203 dogs receiving definitive-intent radiotherapy. Demographic information, CBC values and details of the radiotherapy protocol were collected. The mean lymphocyte count pre-treatment was 1630.68 cells/μL (SD ± 667.56) with a mean NLR of 3.66 (SD ± 4.53). The mean lymphocyte count mid-treatment was 1251.07 cells/μL (SD ± 585.96) and the mean NLR was 6.23 (SD ± 4.99). There was a significant decrease in the mean lymphocyte count by 351.41 lymphocytes/μL (SD ± 592.32) between pre-treatment and mid-treatment (P <.0001), and a corresponding significant increase in the mean NLR of 0.93 (P =.02). Lymphopenia grade increased in 33.5% of dogs and was significant (P =.03). The ALC decrease was not correlated with the volume irradiated (P =.27), but correlated with the irradiated volume:body weight ratio (P =.03). A subset of patients (n = 35) with additional CBCs available beyond the mid-treatment time point demonstrated significant and sustained downward trends in the ALC compared with baseline. Although severe lymphopenia was rare, these decreases, especially if sustained, could impact adjuvant therapy for their cancer.

AB - Localized radiation therapy can be an effective treatment for cancer but is associated with localized and systemic side effects. Several studies have noted changes in complete blood count (CBC) parameters including decreases in the absolute lymphocyte count (ALC) and increases in the neutrophil:lymphocyte ratio (NLR). These changes could reflect immunosuppression and may contribute to decreased efficacy of immunotherapies used to treat cancer. We hypothesized that dogs would demonstrate decreased ALCs during a course of radiotherapy. A retrospective study was conducted on 203 dogs receiving definitive-intent radiotherapy. Demographic information, CBC values and details of the radiotherapy protocol were collected. The mean lymphocyte count pre-treatment was 1630.68 cells/μL (SD ± 667.56) with a mean NLR of 3.66 (SD ± 4.53). The mean lymphocyte count mid-treatment was 1251.07 cells/μL (SD ± 585.96) and the mean NLR was 6.23 (SD ± 4.99). There was a significant decrease in the mean lymphocyte count by 351.41 lymphocytes/μL (SD ± 592.32) between pre-treatment and mid-treatment (P <.0001), and a corresponding significant increase in the mean NLR of 0.93 (P =.02). Lymphopenia grade increased in 33.5% of dogs and was significant (P =.03). The ALC decrease was not correlated with the volume irradiated (P =.27), but correlated with the irradiated volume:body weight ratio (P =.03). A subset of patients (n = 35) with additional CBCs available beyond the mid-treatment time point demonstrated significant and sustained downward trends in the ALC compared with baseline. Although severe lymphopenia was rare, these decreases, especially if sustained, could impact adjuvant therapy for their cancer.

KW - canine

KW - dog

KW - immunosuppression

KW - lymphopenia

KW - radiation therapy

UR - http://www.scopus.com/inward/record.url?scp=85071956924&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85071956924&partnerID=8YFLogxK

U2 - 10.1111/vco.12531

DO - 10.1111/vco.12531

M3 - Article

C2 - 31424596

AN - SCOPUS:85071956924

JO - Veterinary and Comparative Oncology

JF - Veterinary and Comparative Oncology

SN - 1476-5829

ER -