Discussion
Tuberculosis (TB) is an infectious disease caused by the Mycobacterium tuberculosis complex, characterized by granulomas with caseous necrosis. In contrast, lung cancer is a malignant tumor resulting from genetic mutations due to various factors leading to abnormal cell proliferation. According to studies conducted in China, the incidence of TB can increase the risk of developing lung cancer[6]. It has been found that in pulmonary TB lesions of mice, most squamous cells exhibit abnormally high proliferative activity[7]. Cytokines produced from TB infection, such as TGF-β and IL-10, have immunosuppressive properties, which can enhance the incidence of tumors[8]. During the progression of lung cancer, cytokines like IL-4, IL-10, and TGF-β1 are produced. These factors assist in TB evasion from immune detection[9]. Moreover, some studies suggest that TB dissemination may occur during clinical lung cancer immunotherapy, but the precise mechanisms still require further investigation[10]. Compared to patients with only lung cancer or TB, those afflicted by both conditions have a shorter average survival period, with even shorter life expectancy for those with active TB[11].
The clinical symptoms of both lung cancer and TB have many similarities. In this case, the patient primarily presented with symptoms of coughing and hemoptysis, which are nonspecific. The gold standard for diagnosing TB is a positive sputum culture for Mycobacterium tuberculosis, although the positivity rate is relatively low[12]. At this juncture, radiographic examinations are crucial for both diagnosis and differential diagnosis. CT scans have a high accuracy rate, over 90%, in diagnosing concurrent TB and lung cancer, with common signs including pleural adhesions, pleural retraction, bronchial narrowing, and bronchial obstruction[13]. However, CT scans have a lower specificity for fibrotic changes due to benign lesions, leading to frequent false-positive results[14]. There have been numerous recent reports on the diagnostic use of MRI for thoracic diseases, where MRI can predict changes in TB lesions based on T2 signal intensity[15]. In recent years, 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET/CT) imaging has been widely confirmed for the specific diagnosis of malignant tumors[16]. However, due to its high cost and radiation, it is not suitable for screening lung cancer combined with TB. Ultimately, diagnoses of both lung cancer and TB should be confirmed through etiology and histopathology.
There have been some clinical reports on lung cancer concurrent with pulmonary tuberculosis [17,18], but the number remains limited. The majority of patients face the choice between anti-tuberculosis treatment and anti-tumor therapy. Over 80% of lung cancer patients are diagnosed in the intermediate or advanced stages, with the main treatment approaches being concurrent or sequential radiotherapy, chemotherapy, and targeted therapy. Literature has reported poor prognoses for patients with lung cancer and concurrent tuberculosis post-surgical treatment. Smoking history, irritative cough, TNM staging, and the presence of prior tuberculosis lesions have all been identified as risk factors for non-small cell lung cancer patients with active tuberculosis [19]. There is also literature documenting cases of lung adenocarcinoma patients with EGFR mutations treated with afatinib in combination with anti-tuberculosis therapy. Studies indicate that the combination of erlotinib and anti-tuberculosis treatment can effectively control both tuberculosis and the tumor [18].
This paper reports a case of a patient with squamous cell carcinoma of the lung concurrent with pulmonary tuberculosis, who declined genetic mutation testing. Radiotherapy is a commonly used local treatment for malignant tumors. Compared to chemotherapy, its toxic effects on the patient’s liver, kidney functions, blood, gastrointestinal tract, and respiratory system are relatively less. Therefore, we opted for concurrent radiotherapy for lung cancer during the intensive phase of tuberculosis treatment. During the intensive phase of tuberculosis, a combination of four drugs is typically used. Isoniazid is primarily metabolized through the acetylation reaction mediated by NAT2, while rifampin is predominantly deacetylated to form acetylated rifampin. The combined use of these two drugs increases hepatotoxicity[20]. In this report, the patient chose rifapentine capsules, which ensures effective treatment concentrations while reducing side effects[21]. Ethambutol is mainly metabolized in the liver and excreted through the kidneys. Compared to isoniazid and rifampicin, its hepatotoxicity is minimal[22]. Aminoglycosides, such as streptomycin, kanamycin, and amikacin, are primarily metabolized in the kidneys. Among them, streptomycin has a high ototoxicity, but its nephrotoxicity is lower than other aminoglycosides. These drugs exhibit concentration-dependent bactericidal effects; hence, reducing drug dosage is not recommended to prevent an increased risk of drug resistance[23]. Quinolones, like ofloxacin and moxifloxacin, are metabolized in the body through both liver and renal pathways, with approximately 52% through the liver and 45% through the kidneys[23]. During the patient’s anti-tuberculosis treatment and radiotherapy, we continuously monitored their complete blood count, liver and kidney functions, and electrolytes, and no abnormalities were observed.
The patient entered the consolidation phase of combined therapy, during which two or three drugs are typically administered in tandem. The treatment regimen was adjusted to rifapentine capsules, isoniazid tablets, and ethambutol. At this stage, the anti-tuberculosis treatment’s impact on liver and kidney functions is relatively minor. Considering the patient’s upcoming chemotherapy phase, after consultation with the pharmacy department, we opted for a treatment scheme with paclitaxel and carboplatin. Paclitaxel acts by stabilizing microtubules, thus inhibiting tumor cell division. It is primarily metabolized in the liver via CYP2C8 and CYP3A4, different from the metabolism pathway of tuberculosis drugs. However, liver functions still need to be stringently monitored during treatment. Platinum-based drugs play a crucial role in lung cancer chemotherapy. Compared to cisplatin, carboplatin has higher solubility, reduced toxicity, no nephrotoxicity, and reduced ototoxicity[24]. Considering the patient’s financial situation, we selected this regimen. Throughout the treatment, we closely monitored the patient’s liver and kidney functions and blood routine. The patient demonstrated good tolerance and did not experience any adverse reactions.
In conclusion, the patient underwent combined treatment for tuberculosis and lung cancer. Upon evaluation, therapeutic results were observed for both diseases, with significant lesion reduction. However, when treating patients with concurrent lung cancer and pulmonary tuberculosis, the selection of an appropriate treatment plan should consider the patient’s specific circumstances. How to effectively treat both diseases simultaneously to enhance patient survival remains an area we need to further explore.
Informed consent
Written informed consent was obtained from the patient to publish this report in accordance with the journal’s patient consent policy.