Intratumoral bacterial load is associated with survival outcomes in patients with nasopharyngeal carcinoma, according to research published in JAMA Oncology.
The study showed that patients with higher intratumoral bacterial loads had significantly worse disease-free survival, distant metastasis-free survival, and overall survival.
Researchers conducted this retrospective study using data from 2 hospitals in China. The patients included had histologically proven nasopharyngeal carcinoma, did not have distant metastasis at diagnosis, had not received antitumor agents prior to biopsy, and were 18 to 70 years of age.
The researchers first analyzed the intratumoral bacterial load in samples from 96 patients — 48 with relapsed nasopharyngeal carcinoma and 48 without relapse. The 2 groups were matched by age, sex, tumor node metastasis stage, and treatment modalities. Results showed that patients with relapsed disease had a significantly higher bacterial load (P =.01).
The researchers also looked for associations between bacterial load and survival outcomes in a training cohort (n=241), an internal validation cohort (n=233), and an external validation cohort (n=232).
The results showed that disease-free survival was significantly worse for patients with a high intratumoral bacterial load. This was true in the training cohort (hazard ratio [HR], 2.90; 95% CI, 1.72-4.90; P <.001), the internal validation cohort (HR, 3.32; 95% CI, 2.11-5.21; P <.001), and the external validation cohort (HR, 2.24; 95% CI, 1.44-3.47; P <.001).
Similarly, distant metastasis-free survival was significantly worse for patients with a high intratumoral bacterial load in the training cohort (HR, 3.18; 95% CI, 1.58-6.39; P <.001), internal validation cohort (HR, 3.93; 95% CI, 2.31-6.67; P <.001), and external validation cohort (HR, 2.62; 95% CI, 1.45-4.73; P <.001).
Overall survival was significantly worse for patients with a high intratumoral bacterial load in the training cohort (HR, 3.41; 95% CI, 1.90-6.11, P < .001), internal validation cohort (HR, 3.68; 95% CI, 2.29-5.91; P <.001), and external validation cohort (HR, 2.19; 95% CI, 1.37-3.48; P <.001) as well.
Multivariable analyses suggested that intratumoral bacterial load was an independent prognostic factor in each cohort.
Genomic analyses suggested that intratumoral bacteria were more likely to originate from the nasopharynx (69.0%) than from the oral cavity (24.1%) or gut (6.9%). Additional analyses showed a negative association between infiltration of T lymphocytes and a greater intratumoral bacterial load.
“To our knowledge, this cohort study is the first with a large sample size to evaluate the microbial profiles in NPC [nasopharyngeal carcinoma] tumors with different prognoses,” the researchers wrote. “The findings emphasize intratumoral bacterial load as a promising prognostic indicator in NPC.”
Qiao H, Tan XR, Li H, et al. Association of intratumoral microbiota with prognosis in patients with nasopharyngeal carcinoma from 2 hospitals in China. JAMA Oncol. Published online July 14, 2022. doi:10.1001/jamaoncol.2022.2810
This article originally appeared on Cancer Therapy Advisor