IMPORTANCE OF OPEN LUNG BIOPSY IN PATIENTS SUSPECTED INTERSTITIAL LUNG DISEASE

Aim: The purpose of this study was to review the role of surgical lung biopsy techniques in patients with suspected interstitial lung disease to determine the outcomes in terms of diagnosis and management. Methods: Clinical courses and histolopathological reports of twenty four patients with suspected diagnosis of interstitial lung disease on clinical and radiological grounds were reviewed retrospectively. Twenty of the patients had undergone mini thoracotomy and four had undergone video-assisted thoracoscopic lung biopsy. Pathologic diagnosis had been established in all patients. Results: The most frequent diagnosis was sarcoidosis in six patients. As a result of histopathological examination the definite diagnosis and management of 9 (37.5%) patients had changed. Mean post-operative length of hospital stay and chest tube drainage duration was 3.6 days and 2.1 days, respectively. The overall morbidity rate was 12.5% and there was no mortality. Conclusion: Open lung biopsy can safely be performed in patients with suspected interstitial lung disease. The morbidity and mortality is low, length of hospital stay and chest tube drainage durations are relatively short. It alters the diagnosis and management in a significant number of patients.


INTRODUCTION
Interstitial lung disease (ILD) is a generic term representing a heterogeneous group of lung diseases classified together because of several common features (1).Although high resolution computed tomographic (HRCT) scan of the chest may reduce the proportion of patients undergoing surgical lung biopsy, surgery may still be needed to establish an accurate diagnosis, to identify potential treatable causes and to rule out other processes (i.e.infection and malignancy) (2).
The decision to perform lung biopsy in patients with ILD is based on the likelihood that pathological examination of the tissue obtained will yield specific information about the cause of the disease process and whether this information can be used to alter the treatment being received by the patient (3).Surgical lung biopsy includes open and videoassisted thoracic surgery (VATS) procedures.
In this study, we reviewed the role of surgical lung biopsy techniques in patients with suspected ILD to determine the outcomes in terms of diagnosis and management.

MATERIALS AND METHODS
Twenty-four patients with suspected diagnosis of ILD on clinical and radiological grounds who had been referred to our department between July 2003 and April 2006 were included in this study.Patients with a solitary nodule or other focal pulmonary processes were excluded.Twenty open lung biopsies had been performed under general anesthesia.Limited anterior thoracotomy, usually through the fifth intercostal space, had been used.Four patients had undergone VATS.Tissue samples had been obtained from the mostly involved lung area, normal appearing areas, and transitional areas, based on the appearance on HRCT scan.
Frozen section examination was performed when a tumor lesion was suspected during the operation.Most patients had previously been investigated with chest X-ray, HRCT or CT scan, spirometry, bronchoscopy, transbronchial biopsy, bronchial washings, sputum specimen for culture and cytological examinations prior to surgery.Data were collected from patients' medical records: age, sex, previous diagnostic studies, biopsy type, site, and number, histopathology, diagnostic yield, change of therapy, the postoperative length of hospital stay, mean chest tube drainage duration, and post-operative morbidity and mortality were noted.

RESULTS
During the 3-year period, 24 patients had been referred to our department for surgical lung biopsy.Of these 24 patients, 17 were men and 7 were women, with a median age of 51.5 years.Table 1 lists presurgical clinical findings and diagnostic studies.Open lung biopsy had been performed in 20 (83.4%) and VATS had been performed in 4 (16.6%)patients.In 2 patients surgical procedure had changed from VATS to open surgery because of pleural adhesions.Samples had been obtained from lower lobe in 20, upper lobe in 8 and middle lobe in 2 patients.One to three samples from each patient, with a total of 42, had been obtained.All the lung samples were adequate in amount and quality for histopathological examination.Nine patients (37.5%) had received a histological diagnosis not consistent with ILD.In these nine patients (Non-spesific pneumonia in four patients, metastatic carcinoma in three, and adenocarcinoma with pneumonia in two), subsequent management had altered.The list of all histopathological findings is shown on Table 2.
Mean post-operative length of hospital stay was 3.6 days (2-15 days).Mean chest tube drainage duration was 2.1 days.There was no in-hospital mortality in this series of patients.Post-operative complications had been observed in 2 patients who had received VATS procedure.Two patients had had pneumothorax with persistent air leakage for more than one week, which later had resolved with conservative treatment.Post-operative hemorrhage had occurred in one patient who had undergone open lung surgery.This patient had received blood transfusion but rethoracotomy had not been required.

DISCUSSION
Patients with ILD are challenging to treat.Various reported series show a change in management based on biopsy results in 27-73% of patients undergoing this procedure for ILD (3,5,6).As a result of histopathological examination the initial clinico-radiological diagnosis and subsequent diagnosis had changed in 9 (37.5%)patients in our study.
Controversy exists regarding the methods and indications for lung biopsy.The sample size and the number of sites that undergo a biopsy vary considerably.Some surgeons prefer to biopsy a single site, whereas others sample several different areas; the latter approach is strongly recommended (7).In our study group, the preoperative HRCT scans had been reviewed and biopsy samples had been obtained from multiple separate areas, including areas of affected lung with active disease, normal appearing areas, and, most importantly, the transitional areas whose gross appearance is between the other sites.Several studies in the literature have shown that multiple biopsy specimens obtained from different areas of lung are clearly superior to a single biopsy specimen (8)(9)(10)(11).
In conclusion, open lung biopsy can safely be performed in patients with suspected ILD.