Overall survival associated with surgery, radiotherapy, and chemotherapy in metastatic vulvar cancer: A retrospective cohort study based on the SEER database

Abstract

Background: Large cancer registries help analyze the prognosis of rare malignancies, such as advanced vulvar cancer. This study aimed to compare the overall survival (OS) rates of patients with metastatic vulvar cancer who had undergone chemoradiotherapy and radiotherapy alone and identify prognostic factors using data from the Surveillance, Epidemiology, and End Results (SEER) registry.

Methods: In this retrospective cohort study, we used the SEER database to identify patients with metastatic vulvar cancer diagnosed between 2000 and 2019. Propensity score matching was performed to balance the covariates. Kaplan-Meier curves and Cox models were used to analyze OS.

Results: A total of 685 patients were included and divided into chemoradiotherapy and radiotherapy groups, and 400 patients were included after propensity score matching. The chemoradiotherapy group had higher OS in the matched cohort (hazard ratio [HR] = 0.7367; 95% confidence interval [CI]: 0.5906-0.9190; P = 0.0049) than the radiotherapy group, which was similar to that in the pre-matched cohort (P < 0.0001). Patients who had undergone surgery + radiotherapy with or without chemotherapy showed higher OS rates than those who had received radiotherapy with or without chemotherapy for patients aged <75 years and local tumor excision/destruction or surgical removal of the primary site was the recommended surgical choice (P < 0.05). Chemoradiotherapy is sufficient for patients ≥75 years of age.

Conclusions: Patients with metastatic vulvar cancer should undergo surgery if they can tolerate it. Adjuvant chemoradiotherapy should be encouraged because this treatment modality was associated with higher OS than radiotherapy alone.

Keywords: Chemotherapy; Metastatic; Overall survival; Radiotherapy; Surgery; Surveillance, Epidemiology, and End Results (SEER) database; Vulvar cancer.

Graphical abstract

Figure 1

Flowchart of the patient selection procedure. Some patients met more than one of the exclusion criteria, we counted each exclusion criterion separately. Thus the sum case number of excluded patients and analysable patients was greater than 22,091.

Figure 2

Numbers of patients receiving chemoradiotherapy and radiotherapy per year from 2000 to 2019.

Figure 3

Kaplan–Meier survival curves for patients with metastatic vulvar cancer who had undergone chemoradiotherapy or radiotherapy alone, pre- and post-propensity score matching. Overall cohort (A1) pre- and (A2) post-propensity score matching. Surgery group (B1) pre- and (B2) post-propensity score matching. No-surgery group (C1) pre- and (C2) post-propensity score matching. OS: Overall survival. HR: Hazard ratio.

Figure 4

Kaplan–Meier survival curves for the factors age, tumor size, lymph node status, distant metastases, and treatment-related survival benefit or risk in patients with metastatic vulvar cancer in the overall cohort. (A) Different treatment regimens; (B) Chemoradiotherapy, with or without surgery; (C) Age; (D) Tumor size; (E) Lymph node metastasis; and (F) Distant metastasis.

Figure 5

Frequency distribution and Kaplan–Meier survival curves of combinations of treatment in patients with metastatic vulvar cancer per age group. (A) Frequency distribution of different treatment combinations from 2000 to 2019; (B) Distribution of different treatment combinations per age group; (C) OS in patients aged <60 years; (D) OS in patients aged 60–74 years; and (E) OS in patients aged ≥75 years. OS: Overall survival.

Figure 6

Frequency distribution and Kaplan–Meier survival curves of surgical procedures in patients with metastatic vulvar cancer who had undergone comprehensive treatment (surgery + chemoradiotherapy) per age group. (A) Frequency distribution of surgical procedures from 2000 to 2019; (B) Distribution of surgical procedures per age group; (C) OS in the overall cohort; (D) OS in patients aged <60 years; (E) OS in patients aged 60–74 years; and (F) OS in patients aged ≥75 years. OS: Overall survival.