Biomedical subjects

X D Zhou

Publications and source records attributed to X D Zhou.

At least 37 records · Page 2Linked to original sources

PubMed1999

N-acetylglucosaminyltransferase V activity in metastatic models of human hepatocellular carcinoma in nude mice.

N-linked beta 1-6 branched oligosaccharides may contribute directly to the malignant phenotype including metastatic potential of tumour cells. Increased beta 1-6 branching was associated with an increased level of N-acetylglucosaminyltransferase V (GnT V). In this report, the tissues from two metastatic models of human hepatocellular carcinoma (HCC) in nude mice were obtained. GnT V activity and mRNA level were determined. Results showed that GnT V activity in highly metastatic LCI-D20 models (Liver Cancer Institute, passage time: 20 days) (413.1+/-86.4U) was much higher than that in low metastatic LCI-D35 model (passage time 35 days) (155.3+/-31.9U). Northern blot showed that the mRNA level of GnT V in two models had no change. During the selection of a highly metastatic LCI-D20 model, GnT V activity increased from 301.6+/-57.3U to 413.1+/-86.4U while the highly metastatic LCI-D20 model acquired higher metastatic ability after selection. When highly metastatic LCI-D20 model tissues were implanted subcutaneously (s.c.), the GnT V activity decreased dramatically from 413.1+/-86.4U to 94.9U. This is the first report that GnT V activity increased in HCC during metastasis in vivo.

Animals↗

PubMed1998

Cryotherapy for primary liver cancer.

Between November 1973 and December 1996, the in situ freezing of tumor, i.e., cryotherapy, was performed with liquid nitrogen (-196 degrees C) on 235 patients with primary liver cancer (PLC). There were no operative mortalities or severe complications. The 5-year survival was 39.8% for the 235 PLC patients, and 55.4% for the 80 patients with small PLC (< or = 5 cm). When analyzed with respect to treatment modalities without considering the size of the tumor, the 5-year survival was 26.9% for 78 PLC patients treated by cryotherapy alone; 39.6% for 58 PLC patients treated by cryotherapy plus hepatic artery ligation and perfusion; 46.0% for 27 PLC patients treated by cryotherapy for residual tumor plus resection of the main tumor; and 60.4% for 72 PLC patients treated by cryotherapy followed by resection of the frozen tumor. These results indicate that cryotherapy is a safe and effective treatment for PLC.

Adult↗

PubMed1998

Elevated activity of N-acetylglucosaminyltransferase V in human hepatocellular carcinoma.

Cell-surface glycoproteins are regarded as candidates for involvement in the spread of tumor cells. N-linked beta1-6 branched oligosaccharides may contribute directly to the malignant or metastatic phenotypes of tumor cells. Increased beta1-6 branching has been associated with an increased level of N-acetylglucosaminyltransferase V (GlcNAc transferase V), the glycosyltransferase that initiates the beta1-6 branching. In this report, 33 pathologically verified hepatocellular carcinoma (HCC) specimens, six non-cancerous tissues surrounding HCC and five normal liver specimens have been studied. We have quantified N-linked beta1-6 branched oligosaccharides indirectly by measuring GlcNac transferase V activity. The average GlcNac transferase V activities in hepatocellular carcinoma (HCC), noncancerous tissues surrounding HCC and normal liver tissues were 324.2 +/- 269.8, 84.8 +/- 20.7 and 7.0 +/- 6.2 pmol product h(-1) mg protein(-1) (P < 0.05) respectively. In addition, the activity was correlated with the TNM classification of HCC. The average activities of GlcNAc transferase V in stages T1, T2-3 and T4 were 77.6 +/- 57.8, 369.0 +/- 294.7 and 329.9 +/- 205.9 pmol product h(-1) mg protein h(-1) respectively (P < 0.05), showing that the activity of the enzyme in advanced HCC was higher than that in early HCC. Our preliminary results indicated that GlcNAc transferase V activity increased in human HCC and was correlated with its progression.

Adult↗

PubMed1998

Mouse running activity is lowered by Brucella abortus treatment: a potential model to study chronic fatigue.

Chronic fatigue syndrome, which can occur after acute infection and last for years, is characterized by severe and persistent fatigue. Others have reported decreases in mouse running activity following infection and have suggested this may provide an animal model for studying chronic fatigue. Voluntary running is a highly motivated activity in mice, which will often run 5-7 mi/day in our laboratory. Following 2 weeks of acclimation to running wheels with food and water available ad lib, female BALB/c mice received 0.2-mL tail vein injections of killed Brucella abortus (BA) or saline vehicle. Subsequently the effects on voluntary running and grooming behavior were determined. Injection of BA caused an immediate large decrease in running and a lack of grooming. Vehicle injections produced no changes in behavior. After the first several days of reduced running behavior, levels of running and grooming slowly returned back to normal over the next 2-4 weeks, with substantial individual differences in the rate of recovery. The pattern of running during recovery was intriguing in that BA mice first ran at normal levels just after the lights went out, but they stopped after only 1-2 h. As recovery proceeded, they gradually increased the duration of the running bout during the night. Because this model uses voluntary exertion and the ability to run for longer periods of time characterizes recovery, the model may be a good one for studying the biologic underpinnings of chronic fatigue.

Animals↗

PubMed1998

Improved survival with resection after transcatheter arterial chemoembolization (TACE) for unresectable hepatocellular carcinoma.

AIM: This retrospective study was undertaken to analyze the outcome of hepatic resection in hepatocellular carcinomas (HCCs) that shrunk after transcatheter hepatic arterial chemoembolization (TACE) in 65 patients with unresectable HCCs between June 1987 and September 1996. MATERIALS AND METHODS: Among these 65 patients, the median diameter of the tumor was 9.9 cm (5.6-20.0) prior to the first TACE, after 1-6 times of TACE (median 3) the median tumor diameter reduced to 3.7 cm (1.9-12.5) prior to resection. The duration between the last TACE treatment and sequential resection varied from 1 to 9 months (median 2.5). Serum alpha-fetoprotein (AFP) levels were abnormal in 39 out of the 65 patients. In AFP producing HCCs, the AFP level returned to normal (</=20 microgram/l) in 14 out of 39 patients (35.9%). Hepatic segmentectomy, multiple hepatic segmentectomy or partial hepatic resection were performed in 61 patients, right hemihepatectomy in 1, left trisegmentectomy in 2, and left hemihepatectomy in 1. RESULTS: Tumor necrosis ranged from 40 to 100% and pathologically and complete tumor necrosis occurred in 11 patients (16.9%). Of 14 patients with AFP levels decreased to normal, 10 still had microscopic living tumor foci. The 1-, 3- and 5-year survival rates of the 65 patients were 80.0, 65.0 and 56.0% respectively. CONCLUSION: TACE treatment can provide a chance of tumor resection for those patients with initially judged unresectable HCCs, and liver resection should be performed when the tumor has shrunk to be resectable, even when the AFP level has returned to normal.

Adult↗

PubMed1998

Reversed-phase high-performance liquid chromatographic measurement of the P-aminobenzoic acid synthesized by Streptococcus sanguis.

OBJECTIVE: This study investigated the biosynthesis of P-aminobenzoic acid by Streptococcus sanguis and the role of P-aminobenzoic acid in the interaction between Streptococcus sanguis and Streptococcus mutans. METHODS: A reversed-phase high-performance liquid chromatographic technique was used to analyze the P-aminobenzoic acid synthesized by Streptococcus sanguis in an anaerobic atmosphere. RESULTS: The results showed, that (1) the chromatographic method established in this study had good linear relation and the average recovery of P-aminobenzoic acid was 80%, and (2) Streptococcus sanguis did synthesize P-aminobenzoic acid, and the mean concentration of P-aminobenzoic acid was 1.23 micrograms/mL. CONCLUSIONS: The results of this study will help further studies of the factors that may have effects on P-aminobenzoic acid synthesis by Streptococcus sanguis and on the role of P-aminobenzoic acid in the microbial homeostasis of dental plaque.

4-Aminobenzoic Acid↗

PubMed1998

Progress and prospects in hepatocellular carcinoma surgery.

Hepatocellular carcinoma (HCC), the second cause of cancer death in China, is responsible for 130,000 deaths every year. However, as a result of efforts in early detection and small HCC resection, re-resection for subclinical recurrence, cytoreduction and second-stage resection for unresectable HCC, and aggressive palliative surgery other than resection (hepatic artery ligation/cannulation, cryosurgery, etc.), and encouraging improvemental of long-term survival of inpatients has been observed in the authors' institution. In the entire series of 2672 HCC inpatients, the 5-year survival was 4.8% in 1958-70, 12.2% in 1971-83, and 46.7% in 1984-95. The 5-year survival rates were: 61.3% for small HCC resection (n = 645), 33.6% for large HCC resection (n = 950), 48.9% for re-resection (n = 147) calculated from the first resection, 67.9% for second-stage resection (n = 73), and 19.8% for palliative surgery (n = 574, including 73 with second-stage resection). By 1995, 239 HCC patients survived for more than 5 years. Recurrence and metastasis remained the major obstacles to more prolonged survival after HCC surgery. Molecular studies of HCC invasiveness, experimental intervention in the newly established highly metastatic model of human HCC in nude mice in the authors' institution have also been delineated. It is concluded that early detection and small HCC resection remain the major approach to improve survival. Aggressive surgical treatment, such as re-resection and second-stage resection, are also important, and invasiveness-related recurrence will be the next target to be studied.

Animals↗

PubMed1997

Kinetics of cytokine expression and regulation of host protection following infection with molecularly cloned Venezuelan equine encephalitis virus.

In the mouse model, the arbovirus Venezuelan equine encephalitis virus (VEE) replicates in lymphoid tissues prior to either inducing protective immunity (attenuated VEE mutant) or progressing to lethal encephalitis (virulent parent VEE). To investigate the mechanism of the protective response, cytokine gene expression was examined during the course of the primary in vivo immune response to molecularly cloned, virulent VEE and a single-site attenuated VEE mutant, using a quantitative reverse transcriptase-polymerase chain reaction assay. VEE-induced cytokine gene expression was 100-fold elevated over that of untreated controls for IFN-gamma and IL-6 and 10-fold increased for IL-12, IL-10, and TNF-alpha. There was no qualitative difference in cytokine gene induction comparing mice infected with the attenuated and the virulent VEE; however, there were significant differences in the cytokine gene expression kinetics. In mice infected with the attenuated VEE, elevated cytokine gene expression was delayed 24 hr when compared to mice infected with the virulent parent VEE clone at the same dose. Further, IFN-gamma protein secretion by cells from the draining lymph node mimicked the pattern of IFN-gamma gene induction by cells harvested from the same site. IFN-gamma gene expression was elevated at an earlier time point in mice given virulent V3000 24 hr after attenuated V3032 injection compared to mice infected with virulent V3000 alone. The combined V3000/V3032 infection resulted in host protection. Treatment of mice with IL-12 prior to infection with virulent VEE failed to reduce the severity of infection, while anti-IL-12 antibody did not prevent the early protective effect of attenuated virus. In contrast, administration of anti-IFN-alpha/beta antibody prior to VEE infection worsened virulent VEE disease. These results indicate that the attenuated VEE strain elicits a similar but delayed cytokine response compared to the virulent strain, suggesting that the kinetics of cytokine expression and the particular cytokine produced may influence the development of a host protective response. Furthermore, IFN-alpha/beta, but not IL-12, seems to be a major factor in the induction of early protection against VEE infection and disease.

Animals↗

PubMed1997

CD28 dependence of T cell differentiation to IL-4 production varies with the particular type 2 immune response.

T cell differentiation to effector cell function is required for the development of a type 2 immune response. The T cell surface molecule, CD28, is widely considered to be the principal costimulatory molecule involved in T cell differentiation to effector function, including IL-4 production, although this has been difficult to directly examine in vivo. We have studied in vivo differentiation to T cell effector function during two type 2 immune responses in CD28 knockout mice: the systemic immune response to goat anti-mouse IgD Ab and the mucosal immune response following oral inoculation with the nematode parasite, Heligmosomoides polygyrus. Our results show that in C57BL/6 CD28 knockout mice elevations in IL-4 gene expression and protein secretion are blocked during the immune response to goat anti-mouse IgD, and associated increases in serum IgG1 and IgE are also inhibited to untreated control levels. In marked contrast, T cell differentiation to IL-4 production is comparable in C57BL/6 CD28 -/- and CD28 +/+ H. polygyrus-inoculated mice, and elevations in both serum IgG1 and IgE levels occur. These results indicate that the specific kind of type 2 immune response determines whether T cell differentiation to IL-4 production is CD28 dependent.

Animals↗

PubMed1997

High-intensity focused ultrasound in the treatment of experimental liver tumour.

This project aimed to determine the adequacy and accuracy of high-intensity focused ultrasound (HIFU) for ablating experimental liver tumour, and to assess imaging methods for monitoring the therapeutic results. The rabbit liver pseudotumour model was established by injection of Freund's complete adjuvant into the liver; the animals then received HIFU therapy via laparotomy at the focal point of the beam (1.1 MHz, 500 W/cm2, 20 s). The rabbits were sacrificed at scheduled times after treatment and liver tumours were examined histologically. Sequential imaging of the liver tumour was performed before and after HIFU treatment. HIFU accurately destroyed the rabbit liver tumour and induced coagulation necrosis 24 h later. Sonographic imaging studies revealed that characteristic changes occurred. A hyperechoic mass turned to a hypoechoic lesion with no Doppler signal, and a high echogenic rim appeared 24 h after HIFU treatment, correlating well with the pathological changes of a sonoablated lesion. These results verify that HIFU has the power to ablate liver tumour quite adequately and accurately, and that sonography is useful for monitoring sonoablated liver tumour.

Animals↗

PubMed1997

Expression of the integrin alpha5 subunit and its mediated cell adhesion in hepatocellular carcinoma.

Tumor invasion and metastasis are complex processes, requiring the ability of tumor cells to interact with proteins of the extracellular matrix through cell-adhesion molecules on the cell surface. Integrins are heterodimeric membrane glycoproteins, consisting of alpha and beta subunits, which enable cells to recognize adhesive substrates in the extracellular matrix. The roles of the integrin alpha5beta1 in tumor invasion are highlighted by finding that some tumor cells have lost or reduced alpha5beta1 expression. It therefore functions as a negative signaling regulator. Expression of alpha5beta1 and its mediation of cell adhesion in hepatocellular carcinoma (HCC) have not been elucidated. In surgical specimens of HCC we found, by immunohistochemistry and Northern blot analysis, that the alpha5-positive rates in cancerous tissues were lower than the corresponding rates in non-cancerous tissues. Reduced expression of the integrin alpha5 occurred more frequently in HCC with more malignant phenotypes, such as poor differentiation, large size (more than 10-cm in diameter), absence of capsule and high invasion. Reverse transcription/polymerase chain reaction, a more sensitive assay, was used to detect the alpha5 mRNA level in LCID20, a highly metastatic model of human HCC, and LCID35, a low-metastasis model. The results showed that integrin alpha5 was negative in the former and positive in the latter. Cell adhesion assays showed the maximal percentage inhibition of anti-alpha5 mAb on SMMC 7721 cell adhesion to fibronectin to be 68.9 +/- 4.9% at the saturation concentrations of each antibody (200 microg/ml). If anti-alpha5 mAb was combined with anti-beta1 mAb, the inhibition was 74.1 +/- 11.1%. It is concluded that reduced expression of the integrin alpha5 subunit is correlated with more malignant phenotypes of human HCC. Any change in the adhesion of hepatocellular carcinoma cells to fibronectin is mainly dependent upon the function of the integrin alpha5beta1.

Antigens, CD↗

PubMed1997

Iodized oil enhances the thermal effect of high-intensity focused ultrasound on ablating experimental liver cancer.

The influence of the biological medium on high-intensity focused ultrasound (HIFU) therapy for ablating experimental liver cancer was studied. In study 1, the temperature rise in the focal zone in the presence of iodized oil or castor oil was observed in vitro. The results showed that HIFU with iodized oil produced a higher and faster temperature rise than did HIFU with castor oil, whether high-power (500 W/cm2) or relatively low-power (136 W/cm2) conditions were used (P = 0.0008 and P = 0.0004 respectively). With the excised liver samples, the temperature also rose higher and more rapidly after injection of iodized oil into the liver than when castor oil was injected (P = 0.0239), and the target liver tissue revealed more radically and extensive destruction with iodized oil than with castor oil. In study 2, 48 nude mice, bearing primary liver cancer LTNM4 implanted subcutaneously, were randomly divided into four groups. Group I (n = 12) were the controls, group II (n = 12) were injected with iodized oil alone, group III (n = 12) received HIFU treatment, and group IV (n = 12) were exposed to HIFU after iodized oil injection. Significant inhibition of tumor growth was seen in groups III and IV as compared with group I or group II (P < 0.05), the tumor growth inhibition rate on the 28th day after treatment being 87% and 93% respectively. Significantly improved survival was noted in groups III and IV compared with groups I and II (P < 0.05). Histologically, group IV showed more complete tumor necrosis than did group III. These data suggest that HIFU combined with iodized oil might have achieve of synergism, location and targeting in the treatment of liver cancer.

Animals↗

PubMed1997

Management of hepatocellular carcinoma: long-term outcome in 2639 cases.

This paper reports the progress of management in 2639 patients with pathologically proven primary liver cancer (PLC) over the past three decades, and the factors improving long-term outcome. The 5-, and 10-year survival after resection of PLC was 45.9% and 34.8%, respectively, for the whole series (n = 1826), and 61.3% and 45.7%, respectively, for patients with small PLC (< = 5 cm, n = 645). The 5-year survival after cryosurgery was 37.9% for the whole series (n = 191), and 53.1% for patients with small PLC (n = 56). The 5-year survival of 73 patients receiving sequential resection after cytoreduction therapy was 67.8%. The 5-year survival after re-resection for recurrence tumor (n = 148) was 34.5%; 239 patients survived more than 5 years; 124 of these patients (51.9%) were small PLC, and 63 patients survived more than 10 years. Encouraging changes in the prognostic pattern were observed when the PLC data of 1958-1970 (n = 178), 1971-1982 (n = 582) and 1983-1994 (n = 1879) were compared; the 5-year survival being 4.8%, 11.2% and 45.4%, respectively, and the 10-year survival being 4.2%, 7.5% and 34.6%, respectively. Some aspects to prolong survival further were discussed.

Adolescent↗

PubMed1997

Three decades' experience in surgery of hepatocellular carcinoma.

In the author's institution, 2254 patients with hepatocellular carcinoma (HCC) have been treated during 1958-1994. The overall 5-year survival increased from 5.4% (1958-1970), to 11.9% (1971-1982), to 46.2% (1983-1984), which correlated well with the increasing proportion of small HCC in the series (2.6%, 12.1%, and 33.4%, respectively); with the increasing percentage of limited resection (3.1%, 32.2%, and 58.3%); with the increasing number of re-resections for recurrence (0, 27, and 114 patients); and with the increasing number of second stage resections (0, 5, and 67 patients). In our institution, surgical approaches that resulted in significantly prolonging survival included: small HCC resection, re-resection, and cytoreduction followed by sequential resection for initially unresectable HCC. Experience in these 3 aspects suggests: (a) Small HCCs are mainly found by screening using AFP and ultrasonography (US) in a high risk population, and limited resection is the best treatment in patients with compensated liver cirrhosis, the 5-year survival after resection being 62.9% (n = 549). (b) Postoperative monitoring using AFP/US every 2-3 months for 5-10 years after curative resection is needed to detect subclinical recurrence. Limited re-resection is indicated for liver recurrence less than 3 nodules, and lung lobectomy is of proven merit to prolong survival for solitary lung metastasis. Re-resection of subclinical recurrence has resulted in a 10-20% further increase in 5-year survival after curative resection. (c) Palliative surgery other than resection such as hepatic artery ligation (HAL) and cannulation with arterial infusion (HAI), cryosurgery, etc. are superior to palliative resection with residual cancer. (d) Cytoreduction and sequential resection have provided hope for localized unresectable HCC, particularly in the right cirrhotic liver. Multimodality combination treatments such as HAL+HAI+radioimmunotherapy/regional radiotherapy are acceptable cytoreductive therapies. Repeated transcatheter hepatic arterial chemoembolization (TACE) is an alternative nonsurgical approach. Sequential resection is important to eradicate residual cancer after cytoreduction. The 5-year survival of 72 patients with cytoreduction and sequential resection for initially unresectable HCC was 62.1% and resulted in improving 5-year survival in the entire series of unresectable HCC over the 3 periods from 0% to 7.4% to 25.7%, respectively. However, multicentric origin and tumor invasiveness are two major targets to be studied in the control of recurrence and metastasis.

Carcinoma, Hepatocellular↗

PubMed1996

CD40-mediated stimulation contributes to lymphocyte proliferation, antibody production, eosinophilia, and mastocytosis during an in vivo type 2 response, but is not required for T cell IL-4 production.

CD40/CD40 ligand interactions are required for the development of T cell-dependent Ab responses in vivo. The role of these cell surface molecules in contributing to T cell cytokine production and the development of effector populations other than B cells and T cells is, however, less well defined. We have examined the in vivo effects of blocking CD40/CD40 ligand interactions on the type 2 mucosal immune response that follows oral inoculation of mice with the nematode parasite, Heligmosomoides polygyrus. Administration of anti-gp39 (CD40L) mAb (MR1) blocked H. polygyrus-induced elevations in serum IgG1 levels and inhibited elevations in blood eosinophils and mucosal mast cells at day 14 after inoculation. Anti-gp39 mAb markedly inhibited B cell blastogenesis 8 days after H. polygyrus inoculation but did not inhibit elevations in B cell class II MHC expression. Maximal elevations in B7-2 expression required signaling through both CD40 and the IL-4R. Elevations in T cell cytokine gene expression and elevations in the number of IL-4-secreting cells were unaffected by treatment with anti-gp39 mAb, although IL-4 production was inhibited by anti-IL-4R mAb. These results suggest that CD40/CD40L interactions are not required to activate T cells to produce cytokines but are required for the activation and proliferation of other effector cells associated with the type 2 response.

Animals↗

PubMed1996

H. polygyrus: B7-independence of the secondary type 2 response.

The gastrointestinal nematode parasite, Heligmosomoides polygyrus, has been used extensively in experimental studies of host immunity. The pronounced type 2 primary immune response to H. polygyrus is associated with elevated CD4+, TCR-alpha/beta + T cell IL-4 production and elevated serum IgE levels that are blocked by inhibiting CD28/ CTLA4-B7 interactions following in vivo administration of the chimeric fusion protein, CTLA4Ig. In the present study, we have examined the in vivo effects of blocking CTLA4Ig ligands on the secondary type 2 mucosal host protective immune response to this parasite. Our results show that although CD4+, TCR-alpha/beta + cells remain the primary source of elevated IL-4 during the secondary response, the protective immune response and the effector cell activity associated with it is B7-independent as CTLA4Ig administration at the time of challenge does not block (1) elevations in T cell IL-4 gene expression or protein secretion; (2) elevations in serum IgE levels, mucosal mastocytosis, or eosinophilia; or (3) host protection, as measured by adult worm burden and fecundity. These findings suggest that memory T helper cells do not require CD28-B7 interactions for their activation to effector cells that can mediate a host protective type 2 immune response.

Abatacept↗

PubMed1996

mRNA levels of nm23 in murine ascites hepatoma (H22) clones with different lymphatic metastatic potential.

Levels of expression of the nm23 gene inversely correlated with metastatic potential in several rodent tumor model systems and human breast carcinoma. In the present study, we examined nm23 mRNA levels in two murine ascites hepatoma models (H22-16A3-F and H22-A2-P) with different metastatic potentials. Metastatic H22-16A3-F (80% metastatic rate) and non-metastatic H22-A2-P clones were both derived from murine ascites hepatoma (H22). We found that a 0.8-kb nm23 transcript was expressed in both cell clones. The nm23 gene was expressed at a higher level in non-metastatic H22-A2-P: approximately 8.6-fold higher than in metastatic H22-16A3-F. The present data suggest that the expression of nm23 mRNA might be associated with metastasis of murine ascites hepatoma (H22), though heterogeneity of nm23 steady-state expression levels among the H22 clones remains to be investigated.

Animals↗

PubMed1996

Long-term results of surgery for small primary liver cancer in 514 adults.

During 1958-1993, 2030 patients with pathologically proven primary liver cancer (PLC) were retrospectively reviewed. Comparison between small PLC (< or = 5 cm, n = 514) and large PLC (> 5 cm, n = 1516) revealed that small PLC had a higher resection rate (92.4% versus 49.1%), lower operative mortality (1.7% versus 5.2%), a higher percentage of single tumour nodules (78.0% versus 53.4%), a higher percentage of well encapsulated tumour (74.5% versus 35.8%) and higher survival rates after resection (5-year, 63.8% versus 36.6%; 10-year, 46.8% versus 28.5%). No significant difference was found between survival following limited resection (n = 440) and lobectomy (n = 34) in patients with small PLC. Re-resection of any subclinical recurrence or solitary pulmonary metastasis after small PLC resection was done in 70 cases. These results indicate that resection is still the modality of choice for treatment of small PLC; limited resection instead of lobectomy was the key to increasing resectability and decreasing operative mortality; re-resection of subclinical recurrence was important to prolong survival further.

Adult↗