Background: The high risk of developing postherpetic neuralgia (PHN) is associated with severe immunosuppressive diseases. A malignancy itself, as well as surgery, radiotherapy, and other treatments, can lead to changes in the immune status of the body and predispose patients with a malignancy to PHN.
Objective: To investigate the risk factors of postherpetic neuralgia in herpes zoster (HZ) after a malignant tumor and to provide better preventive strategies for clinical practice.
Study design: A retrospective cohort study.
Setting: The Affiliated Hospital of Southwest Medical University, Luzhou, People's Republic of China.
Methods: Patients who developed HZ after being diagnosed with a malignant tumor in the Affiliated Hospital of Southwest Medical University from September 2018 through March 2022 were included in the research. A total of 70 patients were included, including 31 men and 39 women, aged 18- 82 years old (mean, SD: 59.77 ± 13.95). According to the occurrence of PHN, they were divided into a non-PHN (n = 46) and a PHN group (n = 24). General information about the patients was collected, including clinical data, treatment status, and prognosis. Univariate and multivariate analyses were conducted of influencing factors.
Results: A total of 19 factors, including gender, age, and white blood cell count, were included. A univariate analysis showed that there were differences in age, tumor stage, Numeric Rating Scale (NRS-11) score, and the use of antiviral drugs between the 2 groups; these differences were statistically significant, P <0.05. A multifactorial analysis revealed that the acute phase NRS-11 score (odds ratio [OR] = 4.21; 95% CI, 1.59-2.24, P = 0.004), antiviral drug use (OR = 0.28; 95% CI, 0.10-0.82, P = 0.020), and tumor stage (OR = 0.28, 95% CI, 0.08-0.98, P = 0.047) were statistically significant for the effect of PHN occurring in postmalignancy HZ. There was a statistically significant difference between the group with severe pain in the acute phase NRS-11 score and the group with mild and moderate pain, P < 0.05. There was a statistically significant difference between the group treated with 2 antivirals and the group not treated with antivirals, P < 0.05.
Limitations: There are some limitations in our research. It was conducted at a single center, with a single race, and had a small sample size. A larger-scale study should be conducted to analyze the influencing factors of PHN in patients with herpes zoster after a malignant tumor.
Conclusions: The NRS-11 score in the acute phase, whether the use of antiviral drugs in sufficient quantities, and tumor staging are the influencing factors of PHN after malignant tumors.
Keywords: antiviral; herpes zoster; postherpetic neuralgia; risk factors; Malignancy.