Gastrectomy linked to elevated TB risk
Individuals who have undergone gastrectomy for stomach cancer may have an added risk of developing tuberculosis (TB), according to a study from South Korea. However, this elevated risk does not appear to extend to nontuberculous mycobacteria (NTM) lung disease.
“The prevalence of [NTM] lung disease is increasing in many parts of the world,” said the researchers. “[G]astrectomy has previously been reported to increase the risk of mycobacterial infections … however, it remains uncertain whether gastrectomy is a risk factor for the development of NTM lung disease.”
“In our study, it appears that patients who underwent gastrectomy are at higher risk of developing active TB, but not of developing NTM lung disease,” they said.
The retrospective, single-centre study, presented as a poster at APSR 2017, assessed the effect of gastrectomy on TB and NTM lung disease. Researchers analysed 3,113 patients (median age 65 years, 62.9 percent male) who had undergone gastrectomy as a treatment for stomach cancer between January 2009 and December 2016, of whom 52 were diagnosed with active TB while four patients were diagnosed with NTM lung disease.
Individuals with a history of smoking and prior TB infection were at an elevated risk for active TB, while NTM lung disease risk was elevated in females.
Among patients who had undergone gastrectomy, the annual crude incidence rate for active TB was 348 per 100,000 person-years, a number that was significantly higher than that of the national notification rate of active TB among the general public in South Korea in 2016 (standardized incidence rate, 76.8 per 100,000 person-years). [APSR 2017, abstract AP312]
In contrast, the crude incidence rate of NTM lung disease was 26 per 100,000 person-years following gastrectomy, which did not significantly differ from the incidence rate among individuals who had not undergone gastrectomy.
“Careful monitoring and timely diagnosis of TB are needed for patients who undergo gastrectomies, especially those with risk factors such as prior TB infection, comorbidities like other malignancies, and smoking history,” said the researchers.
“However, to avoid unnecessary anti-TB treatment, NTM should be considered a potential pathogen of pulmonary mycobacterial disease in gastrectomy patients accompanying underlying chronic lung disease,” they concluded.