Surgically curable "early" adenocarcinoma in the periphery of the lung

Increased cyclooxygenase 2 (COX-2) expression occurs frequently in precursor lesions of human adenocarcinoma of the lung

A low incidence of lung carcinoma has been reported in cases of prolonged use of aspirin. Cyclooxygenase (COX) 2 expression is frequently seen in adenocarcinoma of the lung, but COX-2 expression in atypical adenomatous hyperplasia (AAH), a possible precursor lesion of adenocarcinoma of the lung, is not known. COX-2 expression was immunohistochemically evaluated in a cohort of 20 cuboidal cell hyperplasias (CCH), 81 atypical adenomatous hyperplasias (AAH), 18 bronchioloalveolar carcinomas (BAC), and 88 invasive adenocarcinomas (I-Ad). The relationship between COX-2 expression and clinicopathologic factors and survival was examined. COX-2 overexpression was detected in over 80% of CCH, AAH, BAC, and I-Ad. However, overexpression was diffuse in AAH (71.6%) and BAC (66.7%). No relationship was found between COX-2 expression and clinicopathological factors or survival. COX-2 expression was most frequently detected in AAH. These findings, taken with previous reports that treatment with COX-2 inhibitor suppresses human colon carcinogenesis, suggest that inhibition of COX-2 may reduce the incidence of human adenocarcinoma of the lung.

Correlation between genetic alterations and histopathological subtypes in bronchiolo-alveolar carcinoma and atypical adenomatous hyperplasia of the lung

Bronchiolo-alveolar carcinoma (BAC) is a type of lung adenocarcinoma characterized by growth along the alveolar wall. It is divided into two subtypes: sclerosing BAC (SBAC), which has central fibrosis, and non-sclerosing BAC (NSBAC), which lacks central fibrosis. We compared the genetic alterations in these two types of BAC with those in atypical adenomatous hyperplasia (AAH). There were 39 cases of SBAC, 19 of NSBAC and 20 of AAH. To detect the loss of heterozygosity (LOH) we used the microsatellite markers D3S1234 and D3S1300 on chromosome 3p, IFNA and D9S144 on 9p, and TP53 on 17p. We also used polymerase chain reaction-SSCP analysis and direct sequencing to examine a point mutation of the p53 gene at exons 5-8. At the TP53 locus, the frequencies of LOH showed a statistical rank-difference correlation among AAH, NSBAC and SBAC. On chromosomes 3p and 9p there were no statistical differences of LOH among AAH, NSBAC and SBAC. We detected a significant statistical rank-difference correlation in the p53 mutation among AAH, NSBAC and SBAC. These findings suggest that a process of multistep carcinogenesis from AAH through NSBAC to SBAC might occur in some cases of adenocarcinoma, and LOH of 3p and 9p might be an early event of carcinogenesis, while the p53 mutation might be a later event.

Favorable and unfavorable morphological prognostic factors in peripheral adenocarcinoma of the lung 3 cm or less in diameter

Many small adenocarcinomas can be detected as a result of recent advances in diagnostic radiology. Since the histological and biological heterogeneity of adenocarcinoma often makes it difficult to predict the outcome of operated patients, clarifying the morphological prognostic factors of the tumor is indispensable to the selection of appropriate treatment. We examined 200 cases of adenocarcinoma of the lung 3 cm or less in diameter (T1). Tumor size, tumor cell characteristics, growth pattern, characteristics of fibrosis, vessel and stromal invasion, and metastasis were evaluated to define favorable and unfavorable morphological prognostic factors by univariate and multivariate statistical analysis. There were no deaths in the 66 cases with more than a 75% of lepidic growth component defined as a region of tumor cells growing along alveolar walls and without stromal invasion, central focus of fibrosis 5 mm or less in maximum diameter, or no elastic fiber framework destruction by tumor cells. Multivariate analysis to investigate unfavorable factors revealed that vascular invasion (P<0.001) and a greater than 25% papillary growth component (P=0.043) were the most significant determinants of an unfavorable outcome. The favorable and unfavorable factors demonstrated in this study will be of great value in selecting the treatment of patients with small peripheral adenocarcinoma of the lung.

Small peripheral glandular lesions detected by screening CT for lung cancer. A diagnostic dilemma for the pathologist

The early detection of lung cancer by helical CT provides an important opportunity for radiologic-pathologic and clinical correlation of borderline glandular lesions. Little is known about the clinical course of atypical adenomatous hyperplasia, solitary noninvasive, nonmucinous BAC, and early-phase invasive adenocarcinomas, therefore, a single protocol for specimen handling and a central tissue registry are essential. The most important separation among the various types of adenocarcinoma is the diagnosis of BAC, a potentially curable malignancy, from invasive adenocarcinoma. Therefore, for small lesions of 2 cm or less, the entire tumor should be processed. For larger lesions, one section per centimeter should be sampled, and if the initial sections show a purely lepidic growth pattern, additional sections should be taken to exclude an invasive component. If foci of invasion are identified, the tumor should be classified as an adenocarcinoma with bronchioloalveolar features. At the International Conference on Screening for Lung Cancer held in October 1997, it was recommended that an international panel be used to reach consensus on difficult lesions of the lung detected by CT screening, and that a tissue bank of these lesions be established to ensure further clinical, radiographic, light microscopic, immunohistochemical, and molecular studies of putative precursor lesions and small carcinomas. Through the collection of these lesions, we can further our understanding of the biologic behavior of lung cancer, particularly because little is known about the progression from a purely lepidic growth pattern to invasive adenocarcinoma.

Lung cancer screening: minimum tube current required for helical CT

PURPOSE

To investigate the minimum tube current required for helical computed tomography (CT) for lung cancer screening.

MATERIALS AND METHODS

Thirty helical scans of the lung were obtained at effective tube currents of 50, 30, 20, 18, 12, 10, and 6 mAs in seven healthy volunteers. Computer-generated nodules 6 mm in diameter that showed ground-glass opacity were superimposed on the images. The image quality and detectability of nodules were evaluated subjectively by six observers. The SDs of measured CT numbers were calculated. The results were analyzed according to location in the lung.

RESULTS

Compared with the subjective quality of images obtained at 50 mAs, the subjective quality of images obtained at 20 mAs was not significantly different. The detectability of nodules was not significantly degraded by reducing the tube current to 20 mAs in the upper zone of the lung, to 12 mAs in the middle zone, or to 18 mAs in the lower zone. The SDs at the apex and base of the lung were larger than those at other levels, and the difference became greater as the dose was reduced.

CONCLUSION

The minimum tube current required for screening helical CT differs for different locations in the lung. An ideal CT protocol for the lung should permit the tube current to be changed during helical scanning.

Prognostic significance of the size of central fibrosis in peripheral adenocarcinoma of the lung

BACKGROUND

The prognostic significance of the characteristics of central fibrosis in peripheral adenocarcinoma of the lung has been reported. However, the prognostic significance of the size of central fibrosis has never been evaluated.

METHODS

A total of 100 consecutive surgically resected peripheral adenocarcinomas of the lung measuring 3.0 cm or less in maximum dimension were reviewed histologically, and the maximum dimension of central fibrosis was measured on conventional hematoxylin and eosin stain.

RESULTS

Median follow-up for patients alive was 54 months. The overall 5-year survival rate was 75%. Twenty-one patients with adenocarcinoma having central fibrosis 5 mm or smaller in maximum dimension had a 5-year survival rate of 100%, whereas the other 79 patients had a 5-year survival less than 70%. Multivariate analysis showed the size of central fibrosis to be an independent prognostic factor as significant as vascular invasion and locoregional lymph node metastasis (p = 0.010, 0.024, and 0.024, respectively).

CONCLUSIONS

The size of central fibrosis is an independent prognostic factor in peripheral lung adenocarcinoma, as significant as the well-established prognostic factors vascular invasion and lymph node metastasis.

Characteristics of small lung cancers invisible on conventional chest radiography and detected by population based screening using spiral CT

Conventional chest radiography (CXR) is a poor diagnostic tool for detecting lung cancers at a surgically curable stage. To determine the visibility of peripheral small lung cancers on CXR, we retrospectively examined the usefulness of CXR using a consecutive series of 44 cases detected on CT screening and later confirmed by histopathology. All cases had been detected by low dose CT during a population based screening trial for lung cancer. The control group consisted of 48 chest radiographs of normal subjects. Tumour diameters ranged from 6 mm to 45 mm, with 95% (42/44) < or = 20 mm, and 5% (2/44) > 20 mm. CXR failed to detect 77% (34/44) of all cancers, including 79% (33/42) < or = 20 mm and 50% (1/2) > 20 mm. Of the 42 lung cancers < or = 20 mm, 74% (31/42) were located in the well penetrated lung zones and 71% (22/31) of these were missed on CXR. 26% (11/42) were concealed by hilar vessels, mediastinum, heart or diaphragm, and all (11/11) of these were missed on CXR. 93% (39/42) of the lung cancers < or = 20 mm were adenocarcinomas and 79% (31/39) of these were missed on CXR. 7% (3/42) were epidermoid carcinomas or small cell carcinomas and 66% (2/3) of these were missed on CXR. The overall accuracy of interpretation on CXR for lung cancers was 61%, sensitivity was 23% and specificity 96%. Although there was an association between presence of lung cancer and positive reading of CXR (chi 2 test of association, p < 0.05), the percentage of positive readings was only 23%. Thus, CXR was poor at visualizing CT detectable lung cancers of < or = 20 mm diameter, which are usually of very low density, and cannot be relied upon for detection of surgically curable small lung cancer.

Conventional clinicopathologic prognostic factors in surgically resected nonsmall cell lung carcinoma. A comparison of prognostic factors for each pathologic TNM stage based on multivariate analyses

BACKGROUND

A number of prognostic factors have been reported for resected nonsmall cell lung carcinoma. None of them, however, has been reported to have greater prognostic impact than the pathologic TNM staging system. The authors evaluated 18 conventional clinicopathologic prognostic factors in each pathologic stage.

METHODS

A retrospective study was conducted on surgically resected 836 lung carcinoma patients, and the following conventional prognostic factors were evaluated in multivariate analyses: age, gender, pack-year smoking, serum carcinoembryonic antigen and squamous cell carcinoma antigen levels, laterality of tumor, clinical N status, histologic type of tumor, greatest tumor dimension, grade of differentiation, pleural involvement, lymphatic invasion, vascular invasion, degree of fibrosing scarring, nuclear atypia, mitotic activity, and curativity of resection.

RESULTS

The overall 5-year survival rate was 63.8%. In 430 cases of pathologic Stage I disease, multivariate analyses revealed 3 significant prognostic factors: clinical N status (P < 0.001), vascular invasion (P = 0.001), and curativity of resection (P < 0.001). In 406 cases of more advanced disease, i.e., pathologic Stage II, IIIA, IIIB, or IV, multivariate analyses revealed 4 factors as significant: histology (P = 0.001), pathologic N status (P < 0.001), tumor size (P < 0.001), and curativity of resection (P = 0.002).

CONCLUSIONS

Conventional clinicopathologic prognostic factors had a different impact on prognosis in each pathologic TNM stage among patients who underwent surgical resection of nonsmall cell lung carcinoma. These factors should be analyzed separately in each pathologic TNM stage.

The prognosis of surgically resected N2 non-small cell lung cancer: the importance of clinical N status

BACKGROUND

Clinical trials dealing with multimodal strategy for N2 non-small cell lung cancer are now being watched with keen interest, and the feasibility of this strategy is to be confirmed. N2 lung cancer, however, is composed of several subgroups with different prognoses. The prognostic factors still remain controversial.

METHODS

Between January 1986 and July 1997, 222 patients with lung cancer underwent surgical intervention at our institute; these patients were eventually given a diagnosis of metastasis to ipsilateral mediastinal lymph nodes. All patients underwent mediastinal lymph node dissection or sampling. Sixteen clinicopathologic factors were investigated by univariable and multivariable analyses to identify significant prognostic factors among resected N2 disease. Clinical N status was evaluated by computed tomographic scan.

RESULTS

The overall 5-year survival was 27%. Multivariable analyses among overall patients revealed 4 significant prognostic factors (P <.05): clinical N2 status, incomplete resection, larger tumor size, and multiple diseased N2 nodes. Based on the result, 32 patients with both clinical N2 status and pathologic multiple N2 nodes showed a 5-year survival of 5%, whereas 76 patients with neither of the factors showed a 5-year survival of 57% (P <.001).

CONCLUSION

The prognosis of surgically resected N2 disease varies tremendously according to the 4 significant prognostic factors. These factors should be clearly described in reporting clinical trials on N2 lung cancer. Clinical N status evaluated by computed tomographic scan should be 1 criterion to perform a clinical trial for N2 disease among a homogeneous population with respect to prognosis.

Prognostic factors in clinical stage I non-small cell lung cancer

BACKGROUND

Management of patients with early-stage lung cancer but a poor prognosis is controversial.

METHODS

Between January 1987 and December 1994, 365 patients with clinical stage I disease underwent surgical resection at our hospital. Eight preoperative clinical variables were entered into univariate and multivariate analyses to determine their impacts on 5-year survival.

RESULTS

The 3-year and 5-year survival rates were 78.1% and 66.5%, respectively. In the multivariate analysis, clinical T2 status and preoperative high serum carcinoembryonic antigen levels were independent significant factors indicative of a poor prognosis (hazard ratio, 2.20 and 1.88, respectively). Patients with both of these factors had 3-year and 5-year survival rates of 65% and 38% (p<0.001), and the risk of death for this subgroup was 4.14 times greater than that of the overall clinical stage I population.

CONCLUSIONS

A subgroup with clinical T2 disease and preoperative high serum carcinoembryonic antigen levels had a significantly poorer prognosis among patients with clinical stage I lung cancer. For this subgroup, a complete preoperative staging workup and multimodal therapy, especially induction chemotherapy, instead of surgical intervention alone could be beneficial.

p16 inactivation in small-sized lung adenocarcinoma: its association with poor prognosis

p16, an inhibitor of cell cycle machinery, is frequently inactivated in non-small cell carcinoma of the lung (NSCCL). To clarify the significance of p16 inactivation in the progression of lung adenocarcinoma, we immunohistochemically evaluated p16 protein status and Rb, p53 and cyclin D1 expression in 51 surgically resected adenocarcinomas that were less than 3 cm in diameter (median follow-up period: 52.5 months). Twenty-one of 51 adenocarcinomas showed negative immunostaining for p16. Twenty adenocarcinomas were also negative for Rb, while 31 and 13 were positive for p53 and cyclin D1, respectively. Loss of p16 expression was significantly correlated with scar grade, lymphatic permeation, lymph node metastasis and clinical stage. Rb protein expression was also inversely correlated with scar grade, pleural involvement and vascular invasion. When the cases were stratified according to the expression of both proteins, the Rb-/p16- subset (7/51) consisted of poorly differentiated adenocarcinoma with a higher grade of invasion. While Rb, p53 and cyclin D1 protein status showed no significant correlations with prognosis, p16 inactivation was significantly correlated with poor prognosis, and the prognosis of Rb-/p16- was the worst among the 4 subsets. Inactivation of p16 may play a role in accelerating scar formation and lymph node metastasis, and may contribute through these mechanisms to poor prognosis in patients with small-sized lung adenocarcinoma.

Outcome of patients with early stage lung cancer

A study was conducted to evaluate the outcomes of 79 patients with early stage lung cancer diagnosed according to the following criteria. Central tumors were located in the segmental bronchi, or more proximally, and tumor invasion was limited to the bronchial wall without lymph node or distant metastases. Peripheral tumors were located distal to the subsegmental bronchi and were less than 2 cm in greatest dimension, and invasion was limited to the visceral pleura, with no lymph node or distant metastases. The 5-year survival rate was 100% for patients with peripheral type early squamous cell carcinoma, 94.6% for those with central-type early squamous cell carcinoma, and 79.3% for those with early adenocarcinoma. The 5-year survival rate for patients with central-type squamous cell carcinoma without pericartilage layer invasion was 97.0%, and that for those with T1N0M0 peripheral squamous cell carcinoma was 100.0%. To define early stage lung cancer as curable, it should be defined as T1N0M0, peripheral squamous cell carcinoma, or central squamous cell carcinoma without pericartilage layer invasion. For other histologic types, some added parameters are needed. The rate of multiple lung cancers was 10.1% and that of multiple primary malignant disease was 13.9%. Thus, careful followup of patients with early stage lung cancer should be carried out, as second malignancies in the lung and elsewhere are commonly detected.

Synchronous double primary lung carcinomas associated with multiple atypical adenomatous hyperplasia

A 71-year-old woman with synchronous bilateral primary lung carcinomas accompanied by multiple atypical adenomatous hyperplasias is described. The patient was found to have bilateral tumors during preoperative workup for the previously detected well differentiated adenocarcinoma of the right lung. Thoracoscopic wedge resection of the left upper lobe was performed to obtain a definitive diagnosis of the left lesion. Although intraoperative diagnosis was made by frozen section as atypical papillary lesion, postoperative diagnosis of this lesion was changed to well differentiated adenocarcinoma accompanied by surrounding atypical adenomatous hyperplasia (AAH). We diagnosed that the bilateral lesions were synchronous primary well differentiated adenocarcinomas independent to each other based on the criteria of Martini and Melamed and performed right upper and mediastinal lymph node dissection. The resected lobe contained not only the primary adenocarcinoma but also multiple small gray nodules which were diagnosed as AAHs. In summary, it was diagnosed that the patient had synchronous double primary lung adenocarcinomas of T1 N0 M0 pathological stage and 12 solitary atypical adenomatous hyperplasias. The patient is doing well with no signs of recurrence 24 months after the operation. This case might be an example of the adenoma-carcinoma sequence of lung cancer. A careful follow-up study is mandatory for this patient with special regard to the further development of lung carcinoma in the future.

Association between p53 mutation and clinicopathological features of non-small cell lung cancer

Genetic alterations in exons 5-8 of the p53 gene, determined by single-strand conformation polymorphism and sequencing analyses, and the clinicopathological characteristics of 108 patients with non-small cell lung cancer were compared. Mutations in this gene were found in 37 of the 108 patients (34%): in 30% (23/76) of those with adenocarcinomas, 46% (12/26) of those with squamous cell, 33% (1/3) of those with large cell and 33% (1/3) of those with adenosquamous carcinomas. No associations between the incidence of p53 mutations and the histological or cytological subtypes of adenocarcinomas were found. The analysis of types of mutations, however, showed that GC transversion was relatively common in papillary and clara subtypes, whereas it accounted for only 17% at most of p53 mutations in tubular and bronchial surface epithelial cell subtypes of adenocarcinomas. Univariate analyses revealed that large tumor size, high nodal stage and positive vascular invasion of non-small cell lung cancers, and high nodal stage and high-grade nuclear atypia of adenocarcinomas were associated significantly with p53 mutations. Multivariate analyses showed that the tumor sizes of non-small cell lung cancer correlated with p53 mutations with marginal significance (P = 0.099) whereas nuclear atypia of adenocarcinomas correlated significantly (P = 0.028). No differences between the overall or relapse-free survival rates of patients with and without p53 mutations in non-small cell lung cancers or adenocarcinomas were found. These findings indicate that p53 mutations in adenocarcinomas of the lung are associated with the malignant phenotype of tumor cells, but not with patient survival.

Microsatellite instability in lung cancer patients 40 years of age or younger

Lung cancer in the young, which has the characteristics of a higher incidence of adenocarcinoma, lower male-to-female ratio of the patients, and less frequent smoking history in the patients, may possibly be associated with genetic predisposition to cancers. We studied six microsatellite loci (D2S123, D3S659, D3S966, D5S346, WT1, and TP53) in 18 surgically treated lung cancer patients aged 25-40 years and nine control patients aged 62-74 to determine the presence of microsatellite instability (MSI) and to correlate its occurrence with clinicopathological characteristics. Of the 18 patients, 11 were female and seven were non-smokers. There were 15 adenocarcinomas and three squamous cell carcinomas, 15 (83%) of which had vascular invasion. MSI was positive in seven (39%) of 18 young patients and one (11%) of nine control patients. Moreover, MSIs in a half or more of six loci examined were demonstrated in five (28%) young patients, whereas no control patients showed such a high frequency of MSI. We observed no significant differences in clinical or pathologic parameters between cases with and without MSI. This result suggests that genetic factors play an important role in the development of lung cancer in young adults.

Nuclear p53 accumulation by small-sized adenocarcinomas of the lung

In order to evaluate the alterations of nuclear p53 accumulation in early stage adenocarcinomas of the lung, nuclear p53 accumulation by small-sized peripheral adenocarcinomas of the lung was examined immunohistochemically. Peripheral adenocarcinomas of the lung, 2 cm or less in diameter, have been classified into two groups; one showing replacing growth of the pulmonary alveolar structure and the other showing non-replacing growth. The former group has been subdivided into three microscopic subtypes: type A, localized bronchioloalveolar carcinoma (LBAC); B, LBAC with foci of pulmonary alveolar structural collapse; and C, LBAC with foci of active fibroblastic proliferation. Type C is thought to be advanced carcinoma, which develops progressively from types A and B. Two of 32 (6%) types A and B carcinomas, 37 of 133 (28%) type C carcinomas and 14 of 35 (40%) non-replacement-type adenocarcinomas showed positive nuclear staining for p53. The positive staining frequency was significantly higher for type C than for types A and B (P < 0.05). These results suggest that nuclear p53 accumulation occurs in the transition from the early to advanced stages of replacement-type adenocarcinoma development and it may be a clinically useful indicator of the degree of tumor malignancy.

Small adenocarcinoma of the lung. Histologic characteristics and prognosis

BACKGROUND

Although there are many reported prognostic indicators for pulmonary adenocarcinoma, the clinicopathologic characteristics and prognostic factors of early stage adenocarcinoma have not been evaluated fully, except for several studies of nonmucinous and sclerosing bronchioloalveolar carcinoma.

METHOD

Two hundred thirty-six surgically resected small peripheral adenocarcinomas measuring 2 cm or less in greatest dimension were reviewed using a simple histologic classification of six types based on tumor growth patterns.

RESULTS

Type A (localized bronchioloalveolar carcinoma [LBAC]) (n = 14) revealed replacement growth of alveolar-lining epithelial cells with a relatively thin stroma. In type B (LBAC with foci of structural collapse of alveoli) (n = 14), fibrotic foci due to alveolar collapse were observed in tumors of LBAC. Type C (LBAC with foci of active fibroblastic proliferation) (n = 141) was the largest group in this study, and foci of active fibroblastic proliferation were evident. Type D (poorly differentiated adenocarcinoma), type E (tubular adenocarcinoma) and type F (papillary adenocarcinoma with a compressive growth pattern) (n = 61) showed compressive and expanding growth. Types A and B showed no lymph node metastasis and the most favorable prognosis (100% 5-year survival) of the six types.

CONCLUSION

Histologic types A and B are thought to be in situ peripheral adenocarcinoma, whereas type C appears to be an advanced stage of types A and B. Conversely, types D, E, and F are small advanced adenocarcinomas with a less favorable prognosis.

The development and progression of adenocarcinoma of the lung

This chapter has briefly reviewed the development and progression of peripheral-type adenocarcinoma of the lung, focusing particularly on bronchioloalveolar carcinoma consisting of the nonmucus-producing cell type with or without sclerosis. Histoloical examination reveals that scar cancers are rare except in cases of diffuse pulmonary fibrosis and that many nonmucus-producing bronchioloalveolar carcinomas appear to develop from atypical adenomatous hyperplasia, which can be called adenoma or very well-differentiated adenocarcinoma, and to progress stepwise. Stepwise progression in malignancy can be disclosed not only by cytological and histological examination but also by proliferative activity of the tumor, such as mitotic activity, the percentage of DNA-synthesizing cells and the frequency of proliferating cell nuclear antigen-positive cells, the mean nuclear DNA content of tumor cells and occurrence of aneuploid cell lines, and abnormalities of oncogenes (c-Ki-ras, myc family, and c-erbB2), such as point mutation, rearrangement, amplification, and tumor suppressor genes (point mutation and deletion) such as p53.