Abstract
Background: The information regarding the optimal treatment of locally advanced lung tumor for achieving a cure remains limited. This is particularly true for an accurate diagnosis of tumor invasion of adjacent structures, especially the aorta. Patients and Methods: Between June 2014 and January 2016, 505 consecutive patients with chest disease underwent surgery at our Institution. Among these patients, five (1.0%) with lung tumor were strongly suspected of having aortic invasion. Their clinical records were retrospectively reviewed to identify factors to accurately diagnose aortic invasion in patients with lung cancer. The data on patient characteristics including modern-era clinical imaging, surgical details, and perioperative outcomes were analyzed. Results: The study population comprised of four males and one female. The histological types were non-small cell carcinoma lung cancer in four cases and metastatic carcinoma from renal cell carcinoma in one. No cases were determined to be negative by both computed tomography and magnetic resonance imaging. However, an intraoperative assessment showed the resectability of lesions without invasion in all cases. Conclusion: The diagnosis of aortic invasion may be overestimated, although aortic invasion is considered an absolute contraindication to surgical management with radical intent. Physicians should pay attention to the possibility of aortic invasion, even if the angle in contact with the tumor indicates a wide field of view, in order to provide a chance for a cure.
Lung cancer is the leading cause of cancer-related death worldwide (1), and approximately one-third of patients with lung cancer are diagnosed with locally advanced disease (2). Nevertheless, the information regarding the optimal curative treatment of this subgroup remains limited and appropriate indications pertaining to surgical treatment are still lacking (2). An accurate diagnosis of T4 tumors is particularly warranted because it can be difficult to determine whether the tumor invades adjacent structures, especially the aorta (3, 4). Consequently, a certain number of cases that are judged to be contraindicated for surgery are expected in clinical practice to be falsely contraindicated. Therefore, the treatment results may be greatly improved by improving the diagnosis of aortic invasion (2). We herein describe consecutive cases of patients who were strongly suspected of having aortic invasion. The data on patient characteristics, surgical details, and perioperative outcomes were analyzed.
Patients and Methods
Patients. This study was approved by the Saitama Cancer Center Ethics Committee (H28-538). The pretreatment evaluation included a medical history, physical examination, a complete blood cell count and analysis of serum chemistry, which included serum electrolytes, liver enzymes, bilirubin, creatinine and coagulation levels. Patients were eligible for this study if they were suspected of having a resectable tumor. Patients were excluded if they had contralateral hilar lymph-node metastasis or a serious pre-existing disease (5). Tumor staging was performed according to chest radiography, enhanced chest and upper abdomen computed tomography (CT), and bronchoscopy findings. Fluorodeoxyglucose (FDG)-positron-emission tomographic (PET) scans were used in clinical staging assessments. Magnetic resonance imaging (MRI) of the brain was routinely employed. Patients underwent a preoperative cardiovascular risk assessment, including electrocardiogram and ultrasound cardiography. The patients' records, including their clinical data, preoperative examination results, histopathological findings and TNM stages, were reviewed. When a lung tumor was strongly suspected of demonstrating aortic invasion, we performed chest 3.0-T MRI examinations to examine such potential aortic invasion using cine display (6). The evaluation of aortic invasion was performed by a Board-certified thoracic radiologist, who was blinded to the operative findings and perioperative outcomes, using a high-resolution 128-detector row CT scanner (7) and cine MRI display of the thorax, including sagittal and coronal sections.
Characteristics of cases with suspected aortic invasion.
Summary of the computed tomographic (CT) findings of patients with suspected aortic invasion.
Surgical technique. The patient was explored through the sixth intercostal space using a 12 mm single port (8). An additional working port (12 mm) was used to move the tumor in the lung and confirm no invasion of the aorta as necessary. After the absence of aortic invasion was confirmed, video-assisted thoracic surgery assisted lobectomy with systematic mediastinal lymph node dissection (en bloc removal of the mediastinal fatty tissue containing the lymph nodes) was performed (5).
Results
Patient characteristics. From June 2014 through January 2016, 505 consecutive chest disease patients underwent surgery at our Institution. Of these, five (1.0%) with lung tumor who were strongly suspected of having aortic invasion were included in this study. The characteristics of these patients are shown in Table I. The study population comprised of four males and one female (mean age=64.6 years; range=50-71 years). All of the patients were Japanese. The histological types were non-small cell carcinoma lung cancer in four and metastatic carcinoma from renal cell carcinoma in one. The mean diameter of the tumor measured 4.8 cm (range=3.2-5.8 cm). Two cases were interpreted as being negative by CT (Figure 1). The mean diameter of the tumor extension to the aorta was 3.7 cm (range=2.3-5.5 cm). The angle of descending aortic invasion in these two cases was 90 and 180 degrees (Table II). The mean standardized uptake value (SUV) of the tumor by PET was 13.4. Three cases were judged to be suspicious for aortic invasion by MRI (Figure 1), and no cases were judged to be negative by both CT and MRI (Table III). After an intraoperative assessment, left upper lobectomy and lymph-nodal dissection was performed in all cases with little difficulty. The average operative time and intraoperative blood loss during the operation was 140 min and 70 ml, respectively. Postoperative complications occurred in three cases. However, the 30-day and 90-day mortality rates were both 0% (Table IV).
Summary of the positron-emission tomographic (PET) and magnetic resonance imaging (MRI) findings of patients with suspected aortic invasion.
Discussion
Aortic invasion is considered an absolute technical and oncological contraindication for surgery (9). Therefore, making an accurate diagnosis of aortic invasion is particularly important for selecting the optimal therapy. When tumor invasion spans a great area, abutting the aorta, then T4 lung cancer as aortic invasion is frequently diagnosed due to there being more than 3 cm of contact between the tumor and the adjacent mediastinum, more than 90 degrees of circumferential contact between the tumor and aorta, and the disappearance of mediastinal fat between the tumor and the adjacent mediastinal structures (10). However, some cases without aortic invasion also undergo curative resection (4). Therefore, aortic invasion may be overestimated (6). Furthermore, treatment results may improve following an accurate diagnosis of aortic invasion.
A: Chest computed tomographic image showing a tumor in the left lower lobe in Case 4. B: Aortic invasion of the left lung tumor was suspected by CT. The left and right images demonstrate CT findings before and after induction treatment, respectively. C: The possibility of invasion was not completely ruled out by a sagittal section on magnetic resonance imaging.
Summary of the perioperative factors of patients in this study.
A: Chest computed tomographic image showing a tumor in the left upper lobe in Case 5. B: Aortic invasion of the left lung tumor was suspected. However, aortic invasion was interpreted as being negative by CT, although invasion was suspected by a coronal section on magnetic resonance imaging (C).
Enhanced CT is generally used to determine aortic invasion. However, CT findings have proven to be unreliable for assessing individual cases (10). We previously experienced a case in which the patient had a left lower lobe cancerous lesion measuring 9 cm that was both wide and long, abutting the descending aorta. No clear fat plane was visible between the aorta and the cancer mass. However, an intraoperative assessment indicated the resectability of the lesion without invasion (4). Furthermore, we recently reported the usefulness of easily diagnosing the absence of aortic invasion using cine MRI without the need for specialized software (6). However, the reported patient did not undergo surgical confirmation of the cine MRI findings. Therefore, we herein described the consecutive cases of patients who were strongly suspected of having aortic invasion and underwent operation in this study. No cases were determined to be negative for aortic invasion on both CT and MRI, and either CT or MRI led to diagnosis of aortic invasion in all cases. Additionally, complete resection without the aorta was performed. These findings suggest limitations in current diagnostic imaging for aortic invasion, despite recent advances in diagnostic imaging (11). Thus, surgical resection of some tumors that are strongly suspected of invading the aorta may be carried out. Indeed, all five cases in the present study were ultimately confirmed not to have aortic invasion.
There are several limitations associated with this study that must be taken into account when considering the present findings. These include the retrospective nature of the study and the fact that it was carried out at a single institution. Nevertheless, the current results highlight an important issue, as complete resection remains the mainstay among curative modalities. Thus, reduced port-surgery might be considered for intraoperative assessment because some cases may lead to false-positive results, even with advances in clinical imaging, without any obvious findings, such as a narrowed lumen of the aorta.
Footnotes
Conflicts of Interests
None declared.
- Received February 5, 2016.
- Revision received April 4, 2016.
- Accepted April 6, 2016.
- Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved
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