Abdominal lymph node metastasis by lymphatic spread through the thoracic duct in patients with non-small-cell lung cancer

A case of concurrent follicular lymphoma and lung cancer requiring differentiation from lymph node metastasis

Lung cancer complicated by follicular lymphoma has rarely been reported in the literature. A 69-year-old male with an abnormal shadow on a chest radiograph was referred to our hospital. A mass in the right lung was seen on chest computed tomography (CT). Positron emission tomography-CT showed fluorodeoxyglucose accumulation in the esophagus and multiple intra-abdominal lymph nodes, in addition to the right lung lesion. The lung lesion was diagnosed as a pulmonary adenocarcinoma after biopsy. Upper and lower gastrointestinal endoscopies did not reveal the presence of a tumor. Open lymph node biopsy was performed to determine the course of treatment, leading to a diagnosis of follicular lymphoma. The patient finally underwent radical resection for lung cancer; the follicular lymphoma was judged to be low-grade and was followed up. When complications involving other organs are detected during systemic examination of a patient with lung cancer, it is necessary to distinguish between metastasis to other organs and complications of other malignant diseases, as this will greatly influence the treatment strategy.

Solitary Uncommon Metastasis in Non-Small Cell Lung Cancer

The major sites of metastasis in non-small cell lung cancer (NSCLC) are bones, the brain, adrenal glands, the liver, the contralateral lung, and distant lymph nodes. Solitary metastasis in an uncommon site is very rare; therefore, it has not often been reported. Identifying whether a solitary lesion is a metastatic lesion is important because it decisively influences the stage and treatment decisions. We report a series of cases of NSCLC diagnosis with uncommon solitary metastasis. (1) A 71-year-old man was diagnosed with poorly differentiated NSCLC after a bronchoscopic biopsy of a tumor in the bronchus of the right middle lobe. A hypermetabolic lesion was observed in the tail of the pancreas using positron emission tomography/computed tomography (PET/CT), and metastasis of NSCLC was confirmed using endoscopic ultrasound fine-needle aspiration (EUS-FNA). (2) A 77-year-old man was diagnosed with squamous cell carcinoma after a bronchoscopic biopsy of a tumor in the bronchus of the left upper lobe. A hypermetabolic lesion was observed in the bilateral lobes of the thyroid gland using PET/CT, and metastasis of the squamous cell carcinoma was confirmed by FNA and cytology. (3) A 79-year-old woman was diagnosed with adenocarcinoma by brushing cytology performed on the apicoposterior segmental bronchus of the left upper lobe. Hypermetabolic lesions were observed using PET/CT in the subcutaneous layer of the right back and the left breast, and metastases of adenocarcinoma were confirmed by biopsies in each lesion. These three patients were treated with platinum-based chemotherapy for stage IV lung cancer. With this case series, we recommend that, when a solitary lesion is observed in NSCLC patients, a tissue biopsy should be performed, even if the lesion is located in an organ where lung cancer metastasis is uncommon.

Novel Drug Delivery Method Targeting Para-Aortic Lymph Nodes by Retrograde Infusion of Paclitaxel into Pigs’ Thoracic Duct

Gastrointestinal cancer with massive nodal metastases is a lethal disease. In this study, using a porcine model, we infused the anti-cancer drug Paclitaxel (PTX) into thoracic ducts to examine the efficiency of drug delivery to intra-abdominal lymph nodes. We established a technical method to catheterize the thoracic duct in the necks of pigs. We then compared the pharmacokinetics of PTX administered intrathoracically with those of systemic (intravenous) infusion. Serum, liver, and spleen concentrations of PTX were significantly lower following thoracic duct (IT) infusion than after intravenous (IV) administration approximately 1–8 h post-infusion. However, PTX levels in abdominal lymph nodes were maintained at relatively high levels up to 24 h after IT infusion compared to after IV infusion. Concentrations of PTX in urine were much higher after IT administration than after IV administration. After IT infusion, the same concentration of PTX was obtained in abdominal lymph nodes, but the serum concentration was lower than after systemic infusion. Therefore, IT infusion may be able to achieve higher PTX doses than IV infusion. IT delivery of anti-cancer drugs into the thoracic duct may yield clinical benefits for patients with extensive lymphatic metastases in abdominal malignancies.

Abdominal lymph node metastasis by lymphatic spread through the thoracic duct in patients with non-small-cell lung cancer

Background

Abdominal lymph node metastasis (ALNM) is common in patients with metastatic non‐small‐cell lung cancer (NSCLC). However, its mechanism of spread remains to be elucidated. We investigated whether thoracic duct has the role as a pathway for ALNM in NSCLC using clinical data.

Methods

We classified ALNM into subgroups by their location and evaluated its prevalence and association with clinical characteristics in 892 patients with metastatic NSCLC. The abdominal lymph nodes were classified into direct or indirect groups depending on whether they drain directly into the trunk (intestinal trunk or lumbar trunks) connected to the cisterna chyli.

Results

One hundred‐five patients (11.8%) had ALNM. The paraaortic lymph node was most commonly involved, followed by the aortocaval, left gastric, paracaval, and celiac lymph nodes. After grouping the patients by location of ALNM, 56 patients (53.3%) with ALNM were in the “direct only” group, only seven patients (6.7%) were in the “indirect only” group, and 42 patients (40.0%) were in “both” groups. In patients whose intrathoracic lesions were limited to the right thorax, there was a significantly lower prevalence of ALNM (3.4% vs. 14.3%, p < 0.001). On multivariate logistic regression analysis of clinical variables, higher N category was associated with increased risk of ALNM.

Conclusions

This study suggests that the thoracic duct is one of the potential routes of lymphatic spread to the abdominal lymph nodes. Clinicians should assess for the presence of ALNM during staging work‐up and follow‐up for NSCLC patients with intrathoracic lesion in left thorax and with high N category.