Peter J. Barth

Placebo-Controlled, Double-Blind, Prospective, Randomized Study on the Effect of Octreotide LAR in the Control of Tumor Growth in Patients With Metastatic Neuroendocrine Midgut Tumors: A Report From the PROMID Study Group

4508 Background: Octreotide is currently used for the control of symptoms in patients with gastroenteropancreatic neuroendocrine tumors (NETs). However, the ability of long-acting somatostatin analogues to control the growth of well-differentiated metastatic NETs is a matter of debate. The analysis of the first randomized, double-blind, placebo-controlled, multicenter, phase IIIb study of octreotide LAR in patients with metastatic NETs of the midgut is presented. METHODS Treatment-naïve patients with histologically confirmed locally inoperable or metastasized well-differentiated NETs and a Karnofsky index >60 were randomized to receive either octreotide LAR 30 mg/month (mo) or placebo for 18 mos, or until tumor progression or death. The primary endpoint was median time to tumor progression. Secondary endpoints included objective tumor response rate (WHO criteria), measured every 3 mos, as well as symptom control and overall survival. This was a planned interim analysis using the Lan-DeMets error spending approach. RESULTS Eighty-five patients (n=43 octreotide LAR; n=42 placebo) have been enrolled to date and data from 67 patients with tumor progressions and 16 deaths (n=7 octreotide LAR; n=9 placebo) are included here. Median time to tumor progression in the octreotide LAR and placebo groups were 14.3 mos and 6 mos, respectively (HR: 0.34; 95% CI: 0.20-0.59; P=0.000072). After 6 mos of treatment, stable disease was seen in 67% and 37.2% of patients treated with octreotide LAR and placebo, respectively. Due to the low number of observed deaths, median survival time could not be estimated. CONCLUSIONS Octreotide LAR significantly lengthens median time to tumor progression compared with placebo in patients with metastatic NETs of the midgut. Patients treated with octreotide LAR had a 66% risk reduction of tumor progression compared with patients receiving placebo. Octreotide LAR demonstrates substantial tumor control and shows a more favorable antiproliferative response than placebo as two-thirds of patients treated with octreotide LAR achieved stable disease at 6 mos. [Table: see text].PURPOSE Somatostatin analogs are indicated for symptom control in patients with gastroenteropancreatic neuroendocrine tumors (NETs). The ability of somatostatin analogs to control the growth of well-differentiated metastatic NETs is a matter of debate. We performed a placebo-controlled, double-blind, phase IIIB study in patients with well-differentiated metastatic midgut NETs. The hypothesis was that octreotide LAR prolongs time to tumor progression and survival. PATIENTS AND METHODS Treatment-naive patients were randomly assigned to either placebo or octreotide LAR 30 mg intramuscularly in monthly intervals until tumor progression or death. The primary efficacy end point was time to tumor progression. Secondary end points were survival time and tumor response. This report is based on 67 tumor progressions and 16 observed deaths in 85 patients at the time of the planned interim analysis. RESULTS Median time to tumor progression in the octreotide LAR and placebo groups was 14.3 and 6 months, respectively (hazard ratio [HR] = 0.34; 95% CI, 0.20 to 0.59; P = .000072). After 6 months of treatment, stable disease was observed in 66.7% of patients in the octreotide LAR group and 37.2% of patients in the placebo group. Functionally active and inactive tumors responded similarly. The most favorable effect was observed in patients with low hepatic tumor load and resected primary tumor. Seven and nine deaths were observed in the octreotide LAR and placebo groups, respectively. The HR for overall survival was 0.81 (95% CI, 0.30 to 2.18). CONCLUSION Octreotide LAR significantly lengthens time to tumor progression compared with placebo in patients with functionally active and inactive metastatic midgut NETs. Because of the low number of observed deaths, survival analysis was not confirmatory.

Octreotide Versus Octreotide Plus Interferon-Alpha in Endocrine Gastroenteropancreatic Tumors: A Randomized Trial

BACKGROUND & AIMS The effect of octreotide plus interferon-alpha versus octreotide monotherapy on the primary study end points of time to treatment failure (progression, death, stop of study treatment) and long-term survival was investigated in patients with progressive metastatic neuroendocrine foregut (mainly pancreatic) and midgut tumors. METHODS One hundred nine of 125 registered patients were randomized starting in January 1995, and 105 patients (51 monotherapy, 54 combination treatment) were finally analyzed in March 2000. Tumor growth was assessed at 3-month intervals by computed tomography or magnetic resonance imaging. Long-term survival was studied up to April 2004 in all analyzed patients and in 9 patients not randomized because of stable disease. RESULTS Partial tumor regression occurred in 2.9%, 1.9%, and 5.7% and stabilization of tumor growth in 44.8%, 27.6%, and 15.2% at 3, 6, and 12 months, respectively, with no significant differences between both treatment arms. In March 2000, 9.5% of patients were in treatment. Time to treatment failure and long-term survival did not differ significantly between the 2 groups, with a median survival of 32 and 54 months for the octreotide and the combination groups, respectively. Survival was longer in patients not randomized because of stable disease (median, 68 months) and in those with low nuclear Ki-67. A trend toward longer survival was shown for patients with slow spontaneous tumor growth before randomization. Patients responding to treatment lived longer than unresponsive patients. CONCLUSIONS Combination treatment was not superior to monotherapy concerning progression-free and long-term survival. Patients responding to treatment and those with slow spontaneous tumor growth had a survival advantage.

Plasma Chromogranin A as Marker for Survival in Patients With Metastatic Endocrine Gastroenteropancreatic Tumors

BACKGROUND & AIMS The prognostic role of plasma chromogranin A in patients with neuroendocrine tumors is unclear. We investigated the role of chromogranin A in predicting survival and hypothesized that chromogranin A mirrors tumor burden and that a rapid increase after a phase of stable plasma chromogranin A levels might predict exploding tumor growth. METHODS Three hundred forty-four patients with metastatic, well-differentiated neuroendocrine tumors were included. A subsample of 102 patients was investigated to correlate radiologically classified tumor burden with plasma chromogranin A. Hepatic tumor burden (0%, 0%-25%, 25%-50%, >50%) was assessed from computed tomography/magnetic resonance imaging scans. Follow-up information until death was generated in regular intervals. RESULTS Plasma chromogranin A levels (U/L) vary between tumor entities (Kruskal-Wallis, P < .001) and were associated with survival time (hazard ratio [hours], 2.14 per one unit in the log10 CgA level scale; 95% confidence interval [CI], 1.75-2.62; P < .001). Chromogranin A levels correlated with hepatic tumor burden (Spearman P = .57; 95% CI, 0.44-0.70; P < .001). Additional extrahepatic tumor load did not relevantly affect plasma chromogranin A. A sudden increase observed in individual patients was paralleled by rapid tumor progress and short survival. CONCLUSIONS Increased plasma chromogranin A in patients with metastatic neuroendocrine tumors is predictive for shorter survival. There was a modest correlation between chromogranin A levels and hepatic tumor burden. We hypothesized further that a sudden increase in individual chromogranin A levels indicates unfavorable outcome.

Mutations of the DPC4/Smad4 gene in neuroendocrine pancreatic tumors

Tumors of the endocrine pancreas are extremely rare, and molecular mechanisms leading to their development are not well understood. A candidate tumor suppressor gene, DPC4, located at 18q21, has recently been shown to be inactivated in half of pancreatic adenocarcinoma xenografts. The close anatomical relationship of the exocrine and endocrine pancreas prompted us to determine the role of DPC4 in the tumorigenesis of 25 pancreatic islet cell tumors (11 insulinomas, nine non-functioning endocrine carcinomas, three gastrinomas, two vipomas). A mutation screening of the highly conserved COOH-terminal domain of DPC4 (exons 8 – 11) was performed by single-strand conformational variant (SSCP) analysis and a PCR-based deletion assay. Five of nine (55%) non-functioning endocrine pancreatic carcinomas revealed either point mutations, small intragenic deletions or homozygous deletion of DPC4 sequences compared to none of the insulinomas, gastrinomas or vipomas. These results suggest that DPC4 is an important target gene promoting tumorigenesis of non-functioning neuroendocrine pancreatic carcinomas.

The Perifollicular and Marginal Zones of the Human Splenic White Pulp: Do Fibroblasts Guide Lymphocyte Immigration?

We investigate the white pulp compartments of 73 human spleens and demonstrate that there are several microanatomical peculiarities in man that do not occur in rats or mice. Humans lack a marginal sinus separating the marginal zone (MZ) from the follicles or the follicular mantle zone. The MZ is divided into an inner and an outer compartment by a special type of fibroblasts. An additional compartment, termed the perifollicular zone, is present between the follicular MZ and the red pulp. The perifollicular zone contains sheathed capillaries and blood-filled spaces without endothelial lining. In the perifollicular zone, in the outer MZ, and in the T cell zone fibroblasts of an unusual phenotype occur. These cells stain for the adhesion molecules MAdCAM-1, VCAM-1 (CD106), and VAP-1; the Thy-1 (CD90) molecule; smooth muscle alpha-actin and smooth muscle myosin; cytokeratin 18; and thrombomodulin (CD141). They are, however, negative for the peripheral node addressin, the cutaneous lymphocyte antigen, CD34, PECAM-1 (CD31), and P- and E-selectin (CD62P and CD62E). In the MZ the fibroblasts are often tightly associated with CD4-positive T lymphocytes, whereas CD8-positive cells are almost absent. Our findings lead to the hypothesis, that recirculating CD4-positive T lymphocytes enter the human splenic white pulp from the open circulation of the perifollicular zone without crossing an endothelium. Specialized fibroblasts may attract these T cells and guide them into the periarteriolar T cell area.

Accuracy of frozen section examination of testicular tumors of uncertain origin.

INTRODUCTION A total of 80-90% of all testicular masses are malignant germ cell tumors. Benign testicular lesions are recognized in approximately 10-20% enabling a testis-preserving surgery on the findings of frozen section examination (FSE). However, there are only sparse information with regard to the reliability of FSE in testicular tumors of uncertain dignity. Therefore, we retrospectively reviewed our experience concerning the reliability of FSE in primary testicular tumors by comparing each FSE result to the final diagnosis. PATIENTS AND METHODS From 1974 to 2000, 354 patients were operated on a testicular tumor. During inguinal exploration and after clamping of the spermatic cord and appropriate dressing, a representative biopsy of the tumor was taken and sent for FSE. In case of malignancy radical orchiectomy was performed, in case of benign findings or in case of a germ cell tumor in a solitary testicle, the tumor was enucleated. Slides of FSE and the permanent sections were reviewed and compared with regard to the histological diagnosis and presence/absence of malignancy. RESULTS Based on FSE, 317 tumors (89.5%) were found to be malignant ((100 seminomas (38.5%), 217 nonseminomas (61.5%)) and 37 tumors (10.5%) were benign (17 epidermoid cysts, 14 Leydig cell tumors, two cystadenomas, two simple cysts, two hemangiomas). Comparing FSE and definitive diagnosis, FSE correctly identified all malignant and benign lesions. There was a failure rate of 10 and 8% to differentiate seminomatous from nonseminomatous tumors and vice versa based on FSE, which, however, was irrelevant for the surgical management. Complications of the enucleations (n = 37) were: testicular atrophy in three cases, testicular hematoma in three cases, orchitis/epididymitis in one case. Not a single case disclosed a local relapse after a mean follow-up of 105 (12-240) months. CONCLUSIONS Intraoperative FSE correctly identified all malignant and benign testicular masses including radical orchiectomy or organ-preserving surgery. Surgical management of testicular tumors based on FSE results is clinically practicable.

CD34 + fibrocytes in invasive ductal carcinoma, ductal carcinoma in situ, and benign breast lesions

Abstract. The present study was undertaken in order to elucidate the question of whether the distribution of stromal CD34+ fibrocytes and smooth muscle actin (SMA)-reactive myofibroblasts differs between benign and malignant lesions of the breast. We investigated a total of 31 ductal carcinomas and 27 specimens with benign lesions of the breast (ductal hyperplasia, sclerosing adenosis, fibroadenoma, phyllodes tumor) and compared the distribution of CD34+ fibrocytes and SMA-reactive myofibroblasts. The stroma of normal breast tissue contained CD34+ fibrocytes, whereas SMA-reactive myofibroblasts were absent. All benign breast lesions exhibited stromal CD34+ fibrocytes and few lesions (fibroadenomas and phyllodes tumor) showed additional SMA-reactive myofibroblasts. In invasive breast cancer the stroma was devoid of CD34+ fibrocytes but a varying number of stromal SMA-reactive myofibroblasts was detectable. In the setting of the present study the loss of CD34+ fibrocytes was specific for invasive breast cancer and ductal carcinoma in situ, whereas SMA-reactive myofibroblasts were observed in different benign and malignant lesions. These findings may be helpful tools in distinguishing benign breast lesions (e.g., sclerosing adenosis) from invasive breast cancer and in characterizing stromal remodeling associated with invasive cancer.

CD34+ fibrocytes, α-smooth muscle antigen-positive myofibroblasts, and CD117 expression in the stroma of invasive squamous cell carcinomas of the oral cavity, pharynx, and larynx

We investigated tumor-free mucosa and squamous cell carcinomas of the oral cavity, the pharynx, and larynx with respect to the presence of stromal CD34+ fibrocytes and α-smooth muscle antigen (SMA)-positive myofibroblasts. Additionally, stromal expression of CD117 was analyzed. A total of 39 squamous cell carcinomas were assessed immunohistochemically. In all cases investigated, CD34+ fibrocytes were found in the tumor-free stroma, whereas α-SMA-positive myofibroblasts were lacking. Areas of lymphocytic infiltration disclosed a focal reduction of CD34+ fibrocytes. CD117 expression was absent from the tumor-free stroma. Of 39 squamous cell carcinomas, 33 were free of stromal CD34+ fibrocytes, and, in 31 carcinomas, stromal α-SMA-positive myofibroblasts occurred at least focally. CD117-positive stromal spindle cells were found in 25 carcinomas. Compared with tumor-free mucosa, the number of tissue mast cells was significantly increased in carcinomas. We conclude that stromal remodeling induced by invasive carcinomas is characterized by a loss of CD34+ fibrocytes and subsequent gain of α-SMA-positive myofibroblasts. The diagnostic impact of this finding is, however, limited by the fact that chronic inflammation may also be accompanied by a focal loss of CD34+ fibrocytes.

K-ras oncogene mutations indicate malignancy in cystic tumors of the pancreas.

OBJECTIVE To evaluate clinical parameters, presurgical diagnostic tests, histologic findings, and the presence of K-ras oncogene mutations in cystic tumors of the pancreas to determine which best predict malignancy. SUMMARY BACKGROUND DATA Because presurgical, intraoperative, and final pathologic differentiation is difficult in cystic tumors of the pancreas, it would be a major benefit to identify markers that accurately predict malignancy in these rare tumors. The role of K-ras oncogene mutations as an indicator of malignancy has not been determined in these tumors. METHODS Nineteen patients with cystic tumors of the pancreas were evaluated, including K-ras mutation analysis based on polymerase chain reaction and restriction digestion assays and direct DNA sequencing, to screen for parameters that accurately predict malignancy. RESULTS All malignant cystic pancreatic tumors (five cystadenocarcinomas and three mucin-producing adenocarcinomas) harbored K-ras mutations at codon 12 or 13. K-ras mutations were also detected in the percutaneous fine-needle aspirates of two of these patients. In contrast, none of nine benign cystadenomas or the solid-papillary neoplasm had K-ras mutations. None of the patients with a benign tumor carrying K-ras wild-type sequences developed recurrent disease after a mean follow-up of 50 months. Seven of the 8 malignant cystic pancreatic tumors, but none of the 11 benign tumors, showed dilatation of the main pancreatic duct on computed tomography or endoscopic retrograde cholangiopancreatography. CONCLUSIONS K-ras mutation analysis seems to be a powerful tool to determine the malignant potential of cystic pancreatic tumors before and after surgery. Dilatation of the main pancreatic duct on computed tomography or endoscopic retrograde cholangiopancreatography is highly suggestive for malignancy in these rare tumors.

CD34+ fibrocytes in neoplastic and inflammatory pancreatic lesions.

Abstract. Besides its function as a matrix-producing cell, the CD34+ fibrocyte has been reported to be an antigen-presenting cell capable of priming naive T cells in situ. Therefore, it has been claimed that the CD34+ fibrocyte may play an important role in host response to tissue damage. The objective of the present study was to analyze the presence and distribution of CD34+ fibrocytes and smooth muscle actin (SMA) reactive myofibroblasts in relation to the underlying pancreatic disease. We investigated a total of 12 pancreatic adenocarcinomas, 7 endocrine tumors of the pancreas, and 8 cases of chronic pancreatitis; in 11 cases, normal pancreatic tissue was available. The stroma of normal pancreatic tissue harbored diffusely scattered CD34+ fibrocytes. Chronic pancreatitis was characterized by an increased number of stromal CD34+ fibrocytes paralleled by a gain of SMA reactive myofibroblasts which were not observed in the normal pancreatic stroma. The stroma of pancreatic ductal adenocarcinomas and endocrine tumors was devoid of CD34+ fibrocytes or showed at least a focal loss of this cell type, whereas SMA reactive myofibroblasts were detected in both endocrine tumors and adenocarcinomas. We conclude that detection of CD34+ fibrocytes may constitute an adjunctive tool in distinguishing chronic pancreatitis from ductal adenocarcinoma since the absence of this cell population strongly favors a neoplastic process. Moreover, CD34+ fibrocytes and myofibroblasts appear to be involved in stromal remodeling associated with chronic pancreatitis and ductal adenocarcinoma.