Small Peripheral Lung Tumors Research Articles

Dose Prescription Methods in Stereotactic Body Radiotherapy for Small Peripheral Lung Tumors: Approaches Based on the Gross Tumor Volume Are Superior to Prescribing a Dose That Covers 95% of the Planning Target Volume.

Background and Purpose:We aimed to validate the usefulness of prescriptions based on gross tumor volume for stereotactic body radiotherapy for small peripheral lung tumors.Materials and Methods:Radiotherapy treatment planning data of 50 patients with small peripheral lung tumors (adenocarcinoma: 24, squamous cell carcinoma: 10, other: 1, unknown: 15) receiving breath-hold computed tomography-guided stereotactic body radiotherapy at our institution during 2013–2016 were analyzed. For each case, 3 dose prescription methods were applied: one based on 95% (PTVD95%) of the planning target volume, one based on 50% of the gross tumor volume (GTVD50%), and one based on 98% (GTVD98%) of the gross tumor volume. The maximum (GTVDmax), minimum (GTVDmin), and mean gross tumor volume dose (GTVDmean) and the dose covering 98% of the gross tumor volume were calculated to evaluate variations in the gross tumor volume dose.Results:Upon switching to GTVD50%, the variations in GTVDmax and GTVDmean decreased significantly, compared with variations observed for PTVD95% (p < 0.01), but the variation in GTVDmin increased significantly (p < 0.01). Upon switching to the GTVD98%, the variation in GTVDmean decreased significantly compared with that observed for PTVD95% (p < 0.01).Conclusion:Switching from prescriptions based on 95% of the planning target volume to those based on 98% of the gross tumor volume decreased variations among cases in the overall gross tumor volume dose. Overall, prescriptions based on 98% of the gross tumor volume appear to be more suitable than those based on 95% of the planning target volume in cases of small peripheral lung tumors treated with stereotactic body radiotherapy.

P3.01-028 Comparison of Touch Imprint Cytology and Section Histopathology in the Diagnostic of the Small Peripheral Lung Tumors: Topic: Morphology

P3.01-028 Comparison of Touch Imprint Cytology and Section Histopathology in the Diagnostic of the Small Peripheral Lung Tumors: Topic: Morphology

A novel four-dimensional radiotherapy planning strategy from a tumor-tracking beam's eye view

To investigate the feasibility of four-dimensional radiotherapy (4DRT) planning from a tumor-tracking beam's eye view (ttBEV) with reliable gross tumor volume (GTV) delineation, realistic normal tissue representation, high planning accuracy and low clinical workload, we propose and validate a novel 4D conformal planning strategy based on a synthesized 3.5D computed tomographic (3.5DCT) image with a motion-compensated tumor. To recreate patient anatomy from a ttBEV in the moving tumor coordinate system for 4DRT planning (or 4D planning), the centers of delineated GTVs in all phase CT images of 4DCT were aligned, and then the aligned CTs were averaged to produce a new 3.5DCT image. This GTV-motion-compensated CT contains a motionless target (with motion artifacts minimized) and motion-blurred normal tissues (with a realistic temporal density average). Semi-automatic threshold-based segmentation of the tumor, lung and body was applied, while manual delineation was used for other organs at risk (OARs). To validate this 3.5DCT-based 4D planning strategy, five patients with peripheral lung lesions of small size (<5 cm3) and large motion range (1.2–3.5 cm) were retrospectively studied for stereotactic body radiotherapy (SBRT) using 3D conformal radiotherapy planning tools. The 3.5DCT-based 4D plan (3.5DCT plan) with 9–10 conformal beams was compared with the 4DCT-based 4D plan (4DCT plan). The 4DCT plan was derived from multiple 3D plans based on all phase CT images, each of which used the same conformal beam configuration but with an isocenter shift to aim at the moving tumor and a minor beam aperture and weighting adjustment to maintain plan conformality. The dose–volume histogram (DVH) of the 4DCT plan was created with two methods: one is an integrated DVH (iDVH4D), which is defined as the temporal average of all 3D-phase-plan DVHs, and the other (DVH4D) is based on the dose distribution in a reference phase CT image by dose warping from all phase plans using the displacement vector field (DVF) from a free-form deformable image registration (DIR). The DVH3.5D (for the 3.5DCT plan) was compared with both iDVH4D and DVH4D. To quantify the DVH difference between the 3.5DCT plan and the 4DCT plan, two methods were used: relative difference (%) of the areas underneath the DVH curves and the volumes receiving more than 20% (V20) and 50% (V50) of prescribed dose of these 4D plans. The volume of the delineated GTV from different phase CTs varied dramatically from 24% to 112% among the five patients, whereas the GTV from 3.5DCT deviated from the averaged GTV in 4DCT by only −6%±6%. For planning tumor volume (PTV) coverage, the difference between the DVH3.5D and iDVH4D was negligible (<1% area), whereas the DVH3.5D and DVH4D were quite different, due to DIR uncertainty (∼2 mm), which propagates to PTV dose coverage with a pronounced uncertainty for small tumors (0.3–4.0 cm3) in stereotactic plans with sharp dose falloff around PTV. For OARs, such as the lung, heart, cord and esophagus, the three DVH curves (DVH3.5D, DVH4D and iDVH4D) were found to be almost identical for the same patients, especially in high-dose regions. For the tumor-containing lung, the relative difference of the areas underneath the DVH curves was found to be small (5.3% area on average), of which 65% resulted from the low-dose region (D < 20%). The averaged V20 difference between the two 4D plans was 1.2% ± 0.8%. For the mean lung dose (MLD), the 3.5DCT plan differed from the 4DCT plan by −1.1%±1.3%. GTV-motion-compensated CT (3.5DCT) produces an accurate and reliable GTV delineation, which is close to the mean GTV from 4DCT. The 3.5DCT plan is equivalent to the 4DCT plan with <1% dose difference to the PTV and negligible dose difference in OARs. The 3.5DCT approach simplifies 4D planning and provides accurate dose calculation without a substantial increase of clinical workload for motion-tracking delivery to treat small peripheral lung tumors with large motion.

Frameless Stereotactic Body Radiotherapy for Lung Cancer Using Four-Dimensional Cone Beam CT Guidance

To quantify the localization accuracy and intrafraction stability of lung cancer patients treated with frameless, four-dimensional (4D) cone beam computed tomography (CBCT)-guided stereotactic body radiotherapy (SBRT) and to calculate and validate planning target volume (PTV) margins to account for the residual geometric uncertainties. Sixty-five patients with small peripheral lung tumors were treated with SBRT without a body frame to 54 Gy in three fractions. For each fraction, three 4D-CBCT scans were acquired: before treatment to measure and correct the time-weighted mean tumor position, after correction to validate the correction applied, and after treatment to estimate the intrafraction stability. Patient-specific PTV margins were computed and subsequently validated using Monte Carlo error simulations. Systematic tumor localization inaccuracies (1 SD) were 0.8, 0.8, and 0.9 mm for the left-right, craniocaudal, and anteroposterior direction, respectively. Random localization inaccuracies were 1.1, 1.1, and 1.4 mm. Baseline variations were 1.8, 2.9, and 3.0 mm (systematic) and 1.1, 1.5, and 2.0 mm (random), indicating the importance of image guidance. Intrafraction stability of the target was 1.2, 1.2, and 1.8 mm (systematic) and 1.3, 1.5, and 1.8 mm (random). Monte Carlo error simulations showed that patient-specific PTV margins (5.8-10.5 mm) were adequate for 94% of the evaluated cases (2-28 mm peak-to-peak breathing amplitude). Frameless SBRT can be safely administered using 4D-CBCT guidance. Even with considerable breathing motion, the PTV margins can safely be kept small, allowing patients with larger tumors to benefit from the advantages of SBRT. In case bony anatomy would be used as a surrogate for tumor position, considerably larger PTV margins would be required.

Molecular characterization of small peripheral lung tumors based on the analysis of fine needle aspirates.

The computed tomography (CT)-based early lung cancer diagnostic technologies allow the detection of very small stage I lung tumors. As part of these screening protocols any suspicious nodule has to be diagnosed morphologically, which requires CT-guided Fine Needle Aspiration, open biopsy or surgery. Fine Needle Aspiration (FNA) cytology is a well-recognised method for a rapid and accurate diagnosis of small lung tumors. Molecular analysis of the FNA specimens could complement cytology diagnosis by the characterization of the biological traits at the preoperative stage. In this study, we aimed to characterize the biological profile of 33 paraffin-embedded transthoracic FNA samples obtained from three groups of lung cancer patients: two groups of small early-detected lung adenocarcinomas (radiologically subsolid and solid nodules) and a third group of small metastatic adenocarcinomas. Genetic analysis was performed by fluorescence in situ hybridization using the four-color LAVysion probe. p53 and Ki-67 protein expression was also evaluated by immunocytochemistry. The samples showed gains for all targets analyzed; two cases had EGFR gene amplification and two cases had MYC amplification. There were no significant differences in the percentage of genetically malignant cells and the expression of Ki-67 among the three groups. However, p53 accumulation was significantly higher in the metastatic group compared to the subsolid early-detected group (P = 0.001). In conclusion, molecular analysis of FNA specimens may provide useful information at preoperative stages. In our series, a good prognostic profile in subsolid early detected adenocarcinomas is suggested.

Radical stereotactic radiosurgery with real-time tumor motion tracking in the treatment of small peripheral lung tumors

BackgroundRecent developments in radiotherapeutic technology have resulted in a new approach to treating patients with localized lung cancer. We report preliminary clinical outcomes using stereotactic radiosurgery with real-time tumor motion tracking to treat small peripheral lung tumors.MethodsEligible patients were treated over a 24-month period and followed for a minimum of 6 months. Fiducials (3–5) were placed in or near tumors under CT-guidance. Non-isocentric treatment plans with 5-mm margins were generated. Patients received 45–60 Gy in 3 equal fractions delivered in less than 2 weeks. CT imaging and routine pulmonary function tests were completed at 3, 6, 12, 18, 24 and 30 months.ResultsTwenty-four consecutive patients were treated, 15 with stage I lung cancer and 9 with single lung metastases. Pneumothorax was a complication of fiducial placement in 7 patients, requiring tube thoracostomy in 4. All patients completed radiation treatment with minimal discomfort, few acute side effects and no procedure-related mortalities. Following treatment transient chest wall discomfort, typically lasting several weeks, developed in 7 of 11 patients with lesions within 5 mm of the pleura. Grade III pneumonitis was seen in 2 patients, one with prior conventional thoracic irradiation and the other treated with concurrent Gefitinib. A small statistically significant decline in the mean % predicted DLCO was observed at 6 and 12 months. All tumors responded to treatment at 3 months and local failure was seen in only 2 single metastases. There have been no regional lymph node recurrences. At a median follow-up of 12 months, the crude survival rate is 83%, with 3 deaths due to co-morbidities and 1 secondary to metastatic disease.ConclusionRadical stereotactic radiosurgery with real-time tumor motion tracking is a promising well-tolerated treatment option for small peripheral lung tumors.

CyberKnife high-dose fractionated stereotactic radiosurgery with tumor tracking: An effective non-surgical treatment alternative for single small peripheral lung tumors

18125 Background: We report preliminary outcomes using CyberKnife radiosurgery with tumor tracking to treat small (&lt;4 cm) peripheral inoperable stage I lung cancers and single pulmonary metastases. Methods: Enrollment of eligible pts began in July 2004. Prior conventional thoracic irradiation and the incorporation of systemic therapy were permitted. Fiducials (3–5) were placed near tumors under CT guidance. Pts received 45–60 Gy in 3 equal 1–2 hour fractions delivered over a 5–9 day period. Results: The median follow-up period of survivors was 12 months (range = 3–24 months). A total of 24 lesions were treated, 15 clinical stage I lung cancers and 9 single lung metastases. Four patients had prior conventional thoracic radiation (17%) and 6 patients received systemic therapy in conjunction with radiosurgery (25%). Two received systemic doses of platinum based doublet chemotherapy, 3 received gefitinib and 1 received sunitinib. Pneumothorax was a complication of fiducial placement in 7 pts, requiring tube thoracostomy in 4. All pts completed treatment with few acute side effects. No unexpected additional toxicities were noted with systemic therapy except for one pt who developed Grade III radiation pneumonitis while receiving gefitinib. A second pt with Grade III radiation pneumonitis had prior extensive conventional thoracic radiation. All tumors responded to treatment at 3 months as seen by a decrease in gross tumor volume. At 12 months 14 CT scans were evaluable. Four lesions responded completely (33%), 2 exhibited a partial response and the remaining 8 were obscured by radiation fibrosis corresponding to the high-dose irradiated volume (57%). Local progression was seen in only 2 single lung metastases at 10 and 12 months. There have been no regional lymph node failures. Four patients have died, 1 of progressive metastatic disease and 3 of comorbid illnesses. Conclusion: CyberKnife high-dose fractionated stereotactic radiosurgery with tumor tracking is an effective well-tolerated treatment option for small peripheral lung tumors, both primary and metastatic. The integration of systemic therapy appears feasible but needs to be further evaluated in clinical trials. No significant financial relationships to disclose.

TH-C-M100J-03: Lung Localization and Initial Shifts Based On Implanted Markers

Purpose: The purpose of this study was to evaluate the daily setup error of small peripheral lungtumors based on implanted markers and stereoscopic x‐rays. Method and Materials:Twenty‐three patients with small peripheral lungtumors were implanted with radiographic markers for localized radiation therapy. Exhale CT scans were used for planning. At treatment, the patients were aligned to skin marks followed by exhale synchronized stereoscopic x‐rays (Exactrac™, BrainLAB). Setup error is evaluated as the shift from initial skin alignment to the implanted x‐ray alignment. The mean, σ mean, and RMS of σ for this data are reported. Results: A total of 790 daily treatment sessions on 23 patients were recorded. In all patients, an evaluation CT of the implanted marker was performed prior to treatment to verify marker location. The mean and σ for the 23 patients from initial setup to x‐ray localization were 0.2 ± 3.8 mm laterally, 1.6 ± 5.3 mm longitudinally, and −0.7 ± 7.8 mm vertically. The RMS error was Lat 5.5 mm, Long 7.7, and Vert 6.4 mm. Conclusion: A large patient study using implanted markers for lungtumor alignment indicated large initial setup shifts from skin marks. Daily random errors on the order of 8mm were reported. The range of these shifts is as large as 3.0 cm in some instances indicating that a small target would potentially be missed without better setup or with localization. The large systematic error is most likely due to the difference in tumor position from exhale breath hold (CT) relative to free breathing exhale (X‐Ray)..Conflict of Interest: This work is supported in part from a research grant from BrainLAB, Inc.

末梢肺腫瘍に対するＣＴガイド下経皮的治療法の現状

Recently, with an increasing uses of the high-resolution CT scan, the effectiveness of detecting tiny tumors in the peripheral lung, such as early stage lung carcinoma, small metastases, or atypical adenomatous hyperplasia, has increased. Video-assisted thoracic surgery is usually employed for many of these cases. However, we considered that a more minimal invasive therapy was necessary for patients who were inoperable due to low cardio-pulmonary function, other complications, severe adhesion and advanced age. Several investigators have applied various types of CT guided percutaneous modalities including percutaneous microwave coagulation therapy (PMCT), radiofrequency ablation (RFA), cryotherapy and photodynamic therapy (PDT) for small peripheral lung tumors experimentally and clinically and examined the possibility of these modalities for small lung tumors in inoperable patients. We reviewed their efficacy and safety. These percutaneous therapies demonstrate that good local control rate of 70-80%. However, recurrence from the tumor margin was of a problem. Pneumothrax occurred in 33.3-53.8% which is a main complication.CT guided percutaneous therapies are considered to be a useful modality as a minimally invasive therapy for peripheral lung tumors with the intent of palliative or curative treatments. The results demonstrated the possibility of percutaneous modalities for the patients with small peripheral lung tumors in near future.

Near infrared thoracoscopy of tumoral protease activity for improved detection of peripheral lung cancer

Improvement in tumor detection using "smart" probes in combination with microcatheter fluorescence thoracoscopy was evaluated in a mouse model. These imaging probes increase in fluorescence intensity after protease activation; cathepsin B is a major activator of the probes used in this study. Lewis lung carcinoma cells were orthotopically implanted in the subpleural lung parenchyma. Two activatable near infrared (NIR) probes with different excitation and emission wavelength were administered intravenously to determine whether wavelength would modulate target to background ratio (TBR). Mice were selectively intubated and thoracoscopy performed. A 0.8 mm outer diameter imaging catheter was used to record simultaneous white-light (anatomic) and NIR (protease expression) images. At both wavelength pairs evaluated (680/700 and 750/780 nm excitation/emission), the intrinsic luminosity differences between tumors and normal lung in uninjected animals was low (p > 0.3 and p = 0.4, respectively and TBR near 1). In mice receiving protease probes IV, tumors were significantly more fluorescent than adjacent lung (p < 0.0005 for 680/700 and p < 0.006 for 750/780) and TBR increased to approximately 9-fold. Confirmatory fluorescence microscopy and immunohistochemistry were similar and revealed that normal lung had very low levels when compared to tumors of cathepsin B and probe fluorescence. In conclusion, protease sensitive imaging probes selective for cathepsin B, imaged with NIR microcatheters, significantly increase the TBR, making small peripheral lung tumors more readily apparent. Such an approach may be a useful adjunct in staging or restaging patients with lung cancer to find minimal disease in the pleural and subpleural space.

P-711 CyberKnife® frameless image-guided radiosurgery with the Synchrony™ motion tracking module in the definitive treatment of small peripheral lung tumors: The Georgetown University Hospital early experience

P-711 CyberKnife® frameless image-guided radiosurgery with the Synchrony™ motion tracking module in the definitive treatment of small peripheral lung tumors: The Georgetown University Hospital early experience

Differences in pulmonary function before vs. 1 year after hypofractionated stereotactic radiotherapy for small peripheral lung tumors

To evaluate long-term pulmonary toxicity of stereotactic radiotherapy (SRT) by pulmonary function tests (PFTs) performed before and after SRT for small peripheral lung tumors. A total of 17 lesions in 15 patients with small peripheral lung tumors, who underwent SRT between February 2000 and April 2003, were included in this study. Twelve patients had primary lung cancer, and 3 patients had metastatic lung cancer. Primary lung cancer was T1-2N0M0 in all cases. Smoking history was assessed by the Brinkman index (number of cigarettes smoked per day multiplied by number of years of smoking). Prescribed radiation doses at the 80% isodose line were 40-60 Gy in 5-8 fractions. PFTs were performed immediately before SRT and 1 year after SRT. Test parameters included total lung capacity (TLC), vital capacity (VC), forced expiratory volume in 1 s (FEV1.0), and diffusing capacity of lung for carbon monoxide (DLCO). PFT changes were evaluated in relation to patient- and treatment-related factors, including age, the Brinkman index, internal target volume, the percentages of lung volume irradiated with >15, 20, 25, and 30 Gy (V15, V20, V25, and V30, respectively), and mean lung dose. There were no significant changes in TLC, VC, or FEV1.0 before vs. after SRT. The mean percent change from baseline in DLCO was significantly increased by 128.2%. Univariate and multivariate analyses revealed a correlation between DLCO and the Brinkman index. One year after SRT as compared with before SRT, there were no declines in TLC, VC, and FEV1.0. DLCO improved in patients who had been heavy smokers before SRT, suggesting a correlation between DLCO and smoking cessation. SRT seems to be tolerable in view of long-term lung function.

Bronchoscopically undiagnosed small peripheral lung tumors

Small peripheral lung cancers (2 cm or less maximum diameter) are often surgically resected, and the survival rate of those patients has been reported to be significantly higher than that of patients with tumors 2.1 cm or more in diameter. We evaluated the status of these small tumors diagnosed during surgery, following unsuccessful transbronchial biopsy procedures. In a retrospective study, 84 consecutive patients, with a maximum diameter of 2 cm or less on chest computed tomography, were enrolled. All underwent surgery for diagnosis. Video-assisted thoracoscopic surgery was performed in 49 cases (58%), Video-assisted thoracoscopic surgery+mini-thoracotomy in ten cases (12%), and an open lung biopsy in 25 cases (30%). Primary lung cancer was found in 40 cases (48%), metastatic lung tumors in three cases (3%), and benign lung tumors in 41 cases (49%). Among the 40 primary lung cancer cases, adenocarcinoma was in 38, squamous cell carcinoma was in one, and small cell carcinoma was in one. The rate of stage IA was 90%. Surgical excision of undiagnosed small peripheral nodules without waiting is necessary if transbronchial biopsy diagnosis is unsuccessful, because of the high rate of stage IA non-small cell lung cancer.

Tumor location cannot predict the mobility of lung tumors: a 3D analysis of data generated from multiple CT scans

Purpose There is limited information available on the three-dimensional (3D) motion of lung tumors. Data derived from multiple planning computed tomographic (CT) scans were used to characterize the 3D movement of small peripheral lung tumors. Methods and materials A total of 29 data sets from patients with Stage I non–small-cell lung cancer (NSCLC), each of which consisted of three “rapid” and three “slow” planning CT scans, were analyzed. All six scans were coregistered, and contoured gross tumor volumes (GTVs) were expanded by 5 mm to derive clinical target volumes (CTVs). Two-dimensional and 3D displacement vectors of the individual CTVs, relative to an “optimal” CTV derived from all six scans, were generated. Tumor mobility was correlated with location. Three-dimensional margins, which had to be added to individual CTVs to ensure coverage of “optimal” CTVs, were determined. Results No significant correlation was observed between the anatomic location of tumors and the extent of mobility in the x, y, and z axes. However, supradiaphragmatic lesions exhibited more mobility, particularly in the craniocaudal direction. The addition of a 3D margin of 5 mm to a single slow CTV ensured full coverage of the “optimal CTV”. Conclusions Lung tumors demonstrate significant mobility in all directions, and this did not closely correlate with anatomic location. Individualized assessment of tumor mobility remains necessary, and is possible when the CTV derived from a single slow scan is used for radiotherapy planning.

Radiofrequency ablation of pulmonary malignant tumors in nonsurgical candidates

Objective: Radiofrequency ablation applies thermal energy with a catheter delivery system, resulting in coagulation necrosis. Radiofrequency ablation is frequently used for hepatic malignant tumors, but few reports exist regarding its use for lung tumors. We report our experience with radiofrequency ablation for the treatment of pulmonary malignant tumors. Methods: We evaluated the results of lung radiofrequency ablation for patients not considered surgical candidates. Indications for radiofrequency ablation were pulmonary malignant tumors in patients with medical comorbidities, pulmonary compromise, or refusal of surgery. Results: Thirty-three lung tumors in 18 patients (12 male, 6 female) were treated with radiofrequency ablation. Tumors included metastatic carcinoma (n = 8), sarcoma (n = 5), and lung cancer (n = 5). Mean age was 60 years (range 27-95 years). Thoracic surgeons performed radiofrequency ablation by minithoracotomy (n = 5) or computed tomography-guided percutaneous methods (n = 13) with patients under general anesthesia in the operating room. Mean length of stay was 3 days (range 1-7 days). Complications included procedure-related pneumothorax in 7 of 13 percutaneous procedures (53.8%), delayed pneumothorax (1/18), pneumonitis/pneumonia (4/18), small pleural effusion (9/18) and transient renal failure (1/18). One death occurred as a result of hemoptysis 19 days after radiofrequency ablation of a central nodule. This patient had also received recent brachytherapy. After a mean follow-up of 6 months (range 1-14 months), radiofrequency ablation had achieved a radiographically determined response in 8 of 12 patients with treated tumors smaller than 5 cm (66.6%). Death with progressive metastatic disease occurred in 7 of 18 patients (38%) during follow-up. Conclusion: This pilot study demonstrates the feasibility of radiofrequency ablation for small peripheral lung tumors. Larger tumors responded poorly. Additional trials are needed to determine safety and efficacy.J Thorac Cardiovasc Surg 2003;125:929-37

Detection of Lung Cancer on Chest Radiographs: Analysis on the Basis of Size and Extent of Ground-Glass Opacity at Thin-Section CT

To evaluate the detection of small peripheral lung tumors on chest radiographs on the basis of the size of the tumor and its extent of ground-glass opacity (GGO) at thin-section computed tomography (CT). Chest radiographs of 75 patients with peripheral carcinomas 20 mm in diameter or smaller (26 localized bronchioloalveolar carcinomas [BACs], 49 other carcinomas) and 60 normal chest radiographs were retrospectively reviewed individually by 10 radiologists. The extent of GGO within the lesions at thin-section CT was reviewed retrospectively. The detection rates for localized BAC and other carcinomas on chest radiographs were calculated and were correlated with tumor size and extent of GGO. The mean sensitivity for detection of small peripheral carcinomas was 58.5% +/- 8.8 (standard error) for localized BAC and was 78.6% +/- 5.1 for other carcinomas (P =.024). Lesions that were smaller than 15 mm in diameter and had an extent of GGO of 70% or greater at thin-section CT were more difficult to detect than tumors that had larger diameters or less extensive GGO (chi(2) = 8.13, df = 1, P =.004). The detection of small peripheral carcinomas on chest radiographs is influenced by tumor size and extent of GGO as seen at thin-section CT.

Prospective study of extended segmentectomy for small lung tumors: the final report

Background. Minimal resection of small lung tumors is still controversial. This study was conducted to clarify whether this type of operation is acceptable.Methods. From January 1992 to December 1994, 73 patients were registered in a multiinstitutional trial of limited resection for peripheral lung tumors less than 2 cm in diameter. The operative procedure consisted of extended segmentectomy in which the cut line of the lung was beyond the burdened segment, confirming N0 disease by intraoperative lymph node examination of frozen sections. The operation was changed to other procedures if the report was positive.Results. All the patients were observed more than 5 years. There were no perioperative deaths and no major complications. A total of 55 patients were finally enrolled in this study. Ten patients died postoperatively, 4 of lung cancer and the remaining 6 died of other diseases, with no signs of recurrence. The 5-year survival rate, excluding these 6 patients, was 91.8%; for all patients including those who died it was 81.8%. A total of 18 patients were not included in this study for various reasons. The decrease in forced vital capacity was 11.3% ± 9.8% compared with the preoperative value.Conclusions. Extended segmentectomy is an alternative method as a standard operation for patients with small peripheral lung tumors, and the loss of lung function is minimal. However, patient selection must be strict, with intraoperative pathologic examination, and a wide margin to the lesion beyond the burdened segment is mandatory.

Early results of a prospective study of limited resection for bronchioloalveolar adenocarcinoma of the lung

Background. We reported that bronchioloalveolar adenocarcinoma (BAC) without active fibroblastic proliferation of the lung had no lymph node and pulmonary metastasis and had a favorable prognosis. However, there has been no prospective trial regarding limited pulmonary resection for this type of BAC. The purpose of this study is to confirm the effectiveness of limited resection for histologically confirmed BAC without active fibroblastic proliferation. Methods. From 1996 through 1999, 42 patients who had small peripheral lung tumors (≦ 20 mm), suspected of being BAC, were enrolled in this trial. The patient population consisted of 24 men and 18 women with a mean age of 58.4 years. Limited resection was completed when BAC, without both active fibroblastic proliferation and lymph node metastasis, was confirmed histologically by intraoperative pathologic examination. Results. Limited resection was completed in 36 patients, wedge resection in 34, and segmentectomy in 2 patients. In 6 patients, the procedure was converted into lobectomy because of pathologic invasive sign in 3, active fibroblastic proliferation in 1, and for other reasons in 2 patients. All patients have been followed for a median follow-up period of 30 months and are alive without sign of recurrence. Conclusions. Our early results indicate that limited resection may be an acceptable alternative to lobectomy for histologically confirmed BAC without active fibroblastic proliferation.

Pulmonary blastoma

Two cases of pulmonary blastoma are reported. One occurred in a 29-year-old man 31 months after a cyst had been excised from the same pericardial-pleural area. The cyst appeared to be of mesothelial origin and, although supported by a cellular stroma, was originally considered to be benign. The morphologic features, location, and possible relationship to a mesothelial lesion suggest an embryonal-mesothelial origin of the tumor. The patient died of recurrent and metastatic disease 9 years after the first resection. The second case is that of a now 74-year-old woman who, over a period of 19 years, has had six separate small peripheral lung tumors excised. They originally resembled fibrous hamartomas but included embryonal-type immature areas and became increasingly more cellular and sarcomatous. The fine structure of the recurrent tumors is that of primitive stroma with few fibrils but no other differentiating features.