Surgical resection for small cell carcinoma of the lung: a retrospective study

Serum markers in small cell lung cancer: opportunities for improvement

Lung cancer is one of the leading causes of death from malignancy worldwide. In particular small cell lung cancers, which comprise about 15-20% of all lung cancers, are extremely aggressive and cure rates are extremely low. Therefore, new treatment modalities are needed and detection at an early stage of disease, as well as adequate monitoring of treatment response is essential in order to improve outcome. In this respect, the use of non-invasive tools for screening and monitoring has gained increasing interest and the clinical applicability of reliable, tumor-related substances that can be detected as tumor markers in easily accessible body fluids is subject of intense investigation. Some of these indicators, such as high LDH levels in serum as a reflection of the disease, have been in use for a long time as a general tumor marker. To allow for improved monitoring of the efficacy of new therapeutic modalities and for accurate subtyping, there is a strong need for specific and sensitive markers that are more directly related to the biology and behavior of small cell lung cancer. In this review the current status of these potential markers, like CEA, NSE, ProGRP, CK-BB, SCC, CgA, NCAM and several cytokeratins will be critically analyzed with respect to their performance in blood based assays. Based on known cleavage sites for cytoplasmic and extracellular proteases, a prediction of stable fragments can be obtained and used for optimal test design. Furthermore, insight into the synthesis of specific splice variants and neo-epitopes resulting from protein modification and cleavage, offers further opportunities for improvement of tumor assays. Finally, we discuss the possibility that detection of SCLC related autoantibodies in paraneoplastic disease can be used as a very early indicator of SCLC.

[Relevance of surgery in small cell lung cancer]

Surgery is the most effective treatment of lung cancer provided that there is complete resection. Even though the results in the early stages of small cell lung cancers (SCLC) are encouraging, many oncologists still consider SCLC a contra-indication. The authors report their experience. They retrospectively reviewed the clinical and pathological characteristics and long-term results of 104 patients (mean age: 58.6, male: N=82 and female: N=22) who underwent lung resection with mediastinal lymphadenectomy (lobectomy: N=51 and pneumonectomy: N=53) for small cell lung cancer between 1984 and 2006. The diagnosis was established before the operation in 49 patients (47.1%) of whom 61.2% (N=30) received neoadjuvant therapy. The survival (5-year survival rate 21.7%, median=18 months), postoperative mortality (deaths: N=6) included, depended on the stage: stage I: N=39, 5-year, 34.3%, median=29; stage II: N=23, 5-year, 26.1%, median=12; stage III: N=37, 5-year, 2.7%, median=12 (p=0.000067). There were no 5-year survivors among the N2 patients. The survival did not depend on the diagnostic aspect of the resection, the non-small cell lung cancer histological patterns or perioperative neoadjuvant and adjuvant therapy. The pneumonectomies were more frequent in case of neoadjuvant treatment (23/30 versus 30/47, p=0.00084). The results and the review of the literature indicate that surgery for small cell lung cancer may provide a cure in stages I and II and should not to be ruled out. The only contra-indication is proven pN2. A multicentre, randomised study on surgery versus medical treatment in the early stages should confirm this conclusion.

Typical and Atypical Pulmonary Carcinoid Tumor Overdiagnosed as Small-Cell Carcinoma on Biopsy Specimens

Seven patients with typical or atypical pulmonary carcinoid tumors overdiagnosed as small-cell carcinoma on bronchoscopic biopsies are described. Bronchial biopsies from 9 consecutive small-cell lung carcinoma patients were used as control group for histologic and immunohistochemical studies (cytokeratins, chromogranin A, synaptophysin, Ki-67 [MIB-1], and TTF-1). The carcinoid tumors presented as either central or peripheral lesions composed of tumor cells with granular, sometimes coarse chromatin pattern, high levels of chromogranin A/synaptophysin immunoreactivity, and low (<20%) Ki-67 (MIB-1) labeling index. The tumor stroma contained thin-walled blood vessels. Small-cell carcinomas always showed central tumor location, finely dispersed nuclear chromatin, lower levels of chromogranin A/synaptophysin, and high (>50%) Ki-67 (MIB-1) labeling index. The stroma contained thick-walled blood vessels with glomeruloid configuration. Judging from this study, overdiagnosis of carcinoid tumor as small-cell carcinoma in small crushed bronchial biopsies remains a significant potential problem in a worldwide sample of hospital settings. Careful evaluation of hematoxylin and eosin sections remains the most important tool for the differential diagnosis, with evaluation of tumor cell proliferation by Ki-67 (MIB-1) labeling index emerging from our review as the most useful ancillary technique for the distinction.

34betaE12 Cytokeratin Immunodetection in the Differential Diagnosis of Small Cell Tumors of Lung

The group of small cell tumors of the lung includes fine following: (1) small cell carcinoma (SCC) of neuroendocrine (NE) origin, (2) poorly differentiated squamous carcinoma, (3) the rare basaloid (basal cell) carcinomas, and (4) malignant lymphomas, primitive neuroectodermal tumors (PNETs), and rhabdomyosarcomas. The differential diagnosis among these entities carries a heavy therapeutic impact but may be difficult in small biopsy specimens or in cytologic material, especially if necrosis or artifactual alterations are present. The use of additional techniques such as immunostaining for NE markers is not always helpful, since immunoreactive chromogranin A is detectable in only a small percentage of small cell carcinomas. It has recently been reported that in the aerodigestive tract 34betaE12 cytokeratin (CK) immunostaining selectively labels non-NE carcinomas, including squamous cell carcinoma, adenocarcinoma, and the rare basaloid carcinoma. We evaluated the role of such CK immunodetection in the differential diagnosis of small cell lung tumors in cytologic and biopsy specimens. Eighty-one lung tumors diagnosed by means of endoscopic bronchial biopsy, fine needle aspirate, or bronchial washing were collected. They included 43 small cell NE carcinomas and 38 cases used as controls (comprehensive of 2 large cell neuroendocrine carcinomas, 4 carcinoid tumors, 30 cases of non-NE lung carcinomas, 2 cases of bronchial infiltration by non-Hodgkin lymphomas). 34betaE12 CK immunoreactivity was found in 29/30 cases of non-NE carcinomas, but in only 3/43 SCCs. The latter showed positivity in only a few scattered cells. The 2 cases of bronchial infiltration by malignant lymphoma as well as the 4 cases of carcinoid tumors and the 2 cases of large cell neuroendocrine carcinomas were negative. These findings were confirmed in the surgical specimens of operatedon cases. We conclude that, in lung carcinoma biopsies showing a small cell pattern, presence of 34betaE12 CK immunoreactivity favors a non-NE carcinoma, whereas its absence supports the diagnosis of SCC. Int J Surg Pathol 8(4):317-322, 2000

Surgery in limited stage small cell lung cancer

The role of surgery in small cell lung cancer (SCLC) is controversial. Surgery has several potential advantages because it may reduce the frequency of local relapses, it does not impede the intensity of chemotherapy, it does not affect the bone marrow, and surgical staging may be of prognostic significance. Several smaller retrospective studies which focus on surgery alone, surgery with adjuvant chemotherapy or radiotherapy, or chemotherapy followed by adjuvant surgery have been reported. Five-year survival data have ranged from 10-50% according to stage, both T-status and nodal status appearing to be significant prognostic factors. Only one prospective randomized trial has been reported concerning the addition of surgery to chemotherapy alone. This trial does not favour surgery. The reason for this could be a selection bias in the smaller non-randomized studies or a result of stage migration. Nevertheless, surgery may yet play an important role in SCLC, especially in diagnosis and staging, and with new improved non-invasive staging procedures, such as positron emission tomography, resection may lead to cure in selected patients. Prospective randomized studies are needed to settle this issue.

Surgery for combined type small cell lung carcinoma

BACKGROUND

Combined type small cell lung cancer (SCLC) has been reported to occur in, at most, 1% of all cases of SCLC. These tumours consist of SCLC with a component of squamous cell carcinoma and/or adenocarcinoma. The survival of patients with combined and pure SCLC after surgical resection was assessed.

METHODS

From 1977 to 1994 2115 patients with bronchogenic carcinoma underwent pulmonary resection. From this group 26 patients (1.2%) were diagnosed as having combined SCLC and 74 patients (3.5%) as having pure SCLC.

RESULTS

From the 26 patients with combined SCLC (mean age 66.4 years) three were classified as pT1N0M0, eight as pT2N0M0, four as postoperative stage II, and 11 as postoperative stage III. Histological examination showed a component of squamous cell carcinoma in 21 patients. There were 18 (69%) lobectomies, seven (27%) pneumonectomies, and one (4%) segmentectomy. In all patients surgery was thought to be curative. Overall hospital mortality was 4% (n = 1). Cumulative five year survival was 31% for all hospital survivors with combined SCLC postoperative stage I, 50% for those with pT1N0M0, and 25% for those with pT2N0M0 disease. No patients with postoperative stage II and III disease survived for five years. In the 74 patients with pure SCLC hospital mortality was 3% (n = 2); cumulative five year survival was 39% in patients with postoperative stage I disease, 46% for those with pT1N0M0 and 35% for those with pT2N0M0. When compared with pure SCLC, no significant differences in five year survival were evident in patients with postoperative stage I disease.

CONCLUSIONS

Surgical resection in patients with combined SCLC postoperative stage I yields a cumulative five year survival of 31% while for those with stage II and III disease there were no survivors at five years. In patients with stage I combined or pure SCLC surgery can offer a long term disease free interval or may even be curative.