Objective To investigate the prognosis of patients with cervical lymph node oligometastasis after esophageal cancer surgery who underwent different therapeutic modalities.

Methods The retrospective cohort study was conducted. The clinicopathological data of 5 692 pati-ents with esophageal cancer who were admitted to Sun Yat‑sen University Cancer Center from May 2007 to June 2023 were collected. There were 4 473 males and 1 219 females, aged 61 (rang, 55-66)years. Of 5 692 patients, 127 patients developed cervical lymph node oligometastasis, including 23 cases undergoing surgery alone who were divided into the surgery along group, 74 cases under-going radiotherapy, chemotherapy, or combined chemoradiotherapy who were divided into the chemo-radiotherapy group, 30 cases undergoing surgery combined with radiotherapy, chemotherapy, or chemoradiotherapy who were divided into the combined treatment group, respectively. Measure-ment data with skewed distribution were represented as M (range). Count data were expressed as absolute numbers or percentages, and comparisons between groups were performed using the chi‑square test or Fisher exact probability. Baseline differences were adjusted using the inverse probability of treatment weighting (IPTW). The optimal cut‑off value for prognosis was determined using X‑tile software (v3.6.1). Median follow‑up time was calculated using the inverse Kaplan‑Meier method, and missing data were handled by multiple imputations. The Kaplan‑Meier method was used to plot survival curve, and the Log‑rank test was used for survival analysis. Univariate and multivariate analyses were performed using the Cox proportional hazards regression model, and clinicopathological factors with P<0.2 in the univariate analysis were included in the multivariate analysis.

Results (1) Survival situations. The median follow‑up time for the 127 patients was 47 months, with a median progression‑free survival time of 31 months and a median overall survival time of 53 months. The 1‑, 3‑, and 5‑year progression‑free survival rate were 61.5%, 43.0%, and 36.5%, respectively. The 1‑, 3‑, and 5‑year overall survival rate were 85.6%, 60.2%, and 45.7%, respectively. After IPTW adjustment, the median progression-free survival time of the surgery along group, chemoradiotherapy group, and combined treatment group were 55, 23, and 61 months, respectively. The 1‑, 3‑, and 5‑year progression‑free survival rate of the surgery along group were 72.9%, 69.7%, and 43.6%, versus 61.1%, 37.3%, and 32.6% for the chemoradiotherapy group, and 60.9%, 52.9%, and 52.9% for the combined treatment group, showing no significant difference among the three groups (χ²=0.34, P>0.05). The median overall survival time of the surgery along group, chemoradiotherapy group, and combined treatment group were not reached, 60 months, and 45 months, respectively. The 1‑, 3‑, and 5‑year overall survival rate were 87.6%, 82.0%, and 55.1% for the surgery along group, versus 91.3%, 57.4%, and 46.8% for the chemoradiotherapy group, and 87.1%, 64.3%, and 32.2% for the combined treatment group, showing no significant difference among the three groups (χ²=0.10, P>0.05). (2) Prognosis analysis. After IPTW adjustment, results of multivariate analysis showed that comorbidity and neoadjuvant therapy were independent risk factors affecting progression‑free survival time for patients with cervical lymph node oligometastasis (hazard ratio=2.25, 2.74, 95% confidence interval as 1.08-5.65, 1.49-5.06, P<0.05), and neoadjuvant therapy and oligometastasis occurring ≤24 months were independent risk factors affecting overall survival time for patients with cervical lymph node oligometastasis (hazard ratio=2.85, 2.08, 95% confidence interval as 1.52-5.34, 1.04-4.17, P<0.05). Results of further analysis showed that the 1‑, 3‑, and 5‑year overall survival rate were 83.7%, 35.3%, and 16.4% for patients with neoadjuvant therapy, versus 91.6%, 72.6%, and 56.2% for patients without neoadjuvant therapy, showing a significant difference between them (χ²=9.26, P<0.05). The 1‑, 3‑, and 5‑year overall survival rate were 84.9%, 53.9%, and 40.1% for patients with oligometastasis occurring ≤24 months, versus 97.8%, 80.5%, and 59.9% for patients with oligometastasis occurring>24 months, showing a signifi-cant difference between them (χ²=9.20, P<0.05).

Conclusions There was no significant difference in prognosis of patients with cervical lymph node oligometastasis after esophageal cancer surgery who underwent surgery alone, chemoradiotherapy or combined treatment. Comorbidity is an inde-pendent risk factor affecting progression‑free survival time for patients with cervical lymph node oligometastasis, oligometastasis occurring ≤24 months is an independent risk factor affecting overall survival time, and neoadjuvant therapy is an independent risk factor affecting both progression‑free survival time and overall survival time.