Pancreatic neuroendocrine tumors (PNETs): incidence, prognosis and recent trend toward improved survival

BACKGROUND

Pancreatic neuroendocrine tumors (PNETs) are uncommon neoplasms that can present with symptoms of hormone overproduction. We evaluated the incidence, prognosis, and temporal trends of PNETs.

PATIENTS AND METHODS

We analyzed all cases of PNETs registered in the Surveillance, Epidemiology, and End Results database from 1973 to 2000. Age-adjusted incidence and survival rates were calculated and survival trends over time were evaluated.

RESULTS

We identified 1483 cases of PNETs. The crude annual incidence per 1,000,000 was 1.8 in females and 2.6 in males and increased with advancing age. The incidence increased over the study period. Most patients (90.8%) had nonfunctional tumors. Advanced stage, higher grade, and age were the strongest predictors of worse survival. Patients with functional tumors had better outcomes than patients with nonfunctional tumors in both univariate and multivariate analysis (P = 0.004). Survival time increased over the period from 1973 to 2000. No differences were seen in the distribution of stage or age at diagnosis among time periods.

CONCLUSION

PNETs are uncommon neoplasms but the incidence may be increasing. Age, grade, stage, and functional status predict survival in patients with PNETs. Survival has improved over time, but this is not explained by earlier diagnosis or stage migration.

Fine-scale genetic mapping of two Pierce's disease resistance loci and a major segregation distortion region on chromosome 14 of grape

A refined genetic map of chromosome 14, which contains the Pierce's disease (PD) resistance locus, was created from three grape mapping populations. The source of PD resistance in these populations was b43-17, a male form of Vitis arizonica Engelm. that is homozygous resistant. The resistance locus segregated as a single dominant gene and mapped as PdR1a in the F1 selection F8909-17 (9621 population) and as PdR1b in a sibling F1 selection F8909-08 (04190 population). These two full sibs inherited either allele of the Pierce's disease resistance locus from the b43-17 parent, which is homozygous at that locus. The 9621 population consisted of 425 progeny and PdR1a mapped between markers VvCh14-56/VvCh14-02 and UDV095 within a 0.6 cM genetic distance. The 04190 population consisted of 361 progeny and PdR1b mapped between markers VvCh14-02 and UDV095/VvCh14-10 within a 0.4 cM distance. Many of the markers present on chromosome 14 were distorted with an excess of female alleles in the 04190 and 04373 population (developed from a cross of V. vinifera L. F2-35 x b43-17) indicating that potential gametophytic factors are present in this region. Common markers from this region within the 9621 population were not distorted except Scu15. When these markers were compared to V. vinifera-based maps of chromosome 14 they were also distorted suggesting the involvement of gametophytic factors, and prompting the identification of this region as Vitis-segregation distortion region 1 (V-SDR1). The refined genetic maps developed from this study can be used to identify and clone genes that confer resistance to Pierce's disease.

MC044h, a phase II trial of sorafenib in patients (pts) with metastatic neuroendocrine tumors (NET): A Phase II Consortium (P2C) study

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Background: Treatment options for metastatic NET, including islet cell carcinoma (ICC) and carcinoid tumor (CT), are limited. These tumors frequently express vascular endothelial growth factor receptor-2 (VEGFR-2) and platelet derived growth factor receptor receptor-β (PDGFR-β). Sorafenib, a small-molecule inhibitor of the VEGFR-2 and PDGFR-β tyrosine kinase domains, is a rational targeted therapy to evaluate in NET. Methods: Eligibility criteria included: ECOG PS = 2, = 1 prior chemotherapy, good organ function and signed informed consent. Prior interferon and prior or concurrent octreotide at a stable dose were allowed. Pts unable to take oral medications, with uncontrolled hypertension or with symptomatic coronary artery disease were excluded. Pts received sorafenib 400 mg po BID. Primary endpoint was response by RECIST in two cohorts (ie, CT and ICC) using separate 2-stage phase II designs. Results: 93 pts were enrolled: (50 CT, 43 ICC). For pts evaluable for the primary endpoint, 4 of 41 (10%) CT pts and 4 of 41 (10%) ICC pts had a PR. There were 3 minor responses (MR = 20–29% decrease in sum of target lesion diameters) in CT pts and 9 MRs in ICC pts for PR+MR rate of 17% for CT pts and 32% for ICC pts. For pts evaluable, 6-month progression-free survival was observed in 8/20 CT and 14/23 ICC pts. Grade 3–4 toxicity occurred in 43% of pts, with skin (20%), GI (7%) and fatigue (9%) most common. Translational studies from tumor tissue will be presented. Conclusions: Sorafenib at 400 mg po BID has modest activity in metastatic neuroendocrine tumors, with frequent grade = 3 toxicity. Supported by NOI CM6225.

No significant financial relationships to disclose.

Pancreatic endocrine tumors (PETs): Incidence and recent trend toward improved survival

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Background: PETs (islet cell tumors) are uncommon and often indolent tumors, but little is known about the incidence of PETs in the US and trends in survival. Methods: The SEER registry was used to identify cases of functional PETs (fPETs) and non-functional PETs (nfPETs) diagnosed from 1973–2000. Benign insulinomas were excluded. Incidence rates were age adjusted to the standard US population for 2000. Results: Of 971 patients with PETs, 824 (85%) were nfPETs, 37 (4%) were malignant insulinomas, 88 (9%) were fPETs other than insulinoma, and data were missing for 22 (2%). The crude annual incidence of PETs (per 100,000) for all ages was 0.1 in females and 0.2 in males. The incidence was highest in the age group >70 years (0.4, Table ). Tumors were localized in 109 (11%), regionally advanced in 228 (23%), and distant metastases were present in 545 (56%). Patients with fPETs were younger than patients with nfPETs (mean age 54.2 vs. 57.6, p=0.038) and had a longer median survival (MS) (47 vs. 30 months (mos), p=0.001) but were as likely to have advanced disease (p=0.50). The 5 and 10 year overall survival was 45.3% vs. 32.7% and 31.7% vs. 18.1% for fPETs vs. nfPETs, respectively. MS was 95 mos for localized PETs, 66 mos in regionally advanced PETs and 19 mos for distant metastases (p<0.001). Race did not influence incidence and survival. On multivariate analysis, only age (p<0.0001) and stage (<0.0001) were independently associated with prognosis but the functional status of the tumor approached significance (p=0.053). Survival has improved over time with longer MS in patients diagnosed in later quartiles of the observation period (p<0.001, Table). This difference is not explained by stage migration, as patients in all four quartiles had a similar stage distribution (p=0.79). Conclusions: PETs are uncommon tumors and the prognosis is highly dependent on the stage and the age of the patients. Patients with fPETs may have a better prognosis than nfPETs. Survival has improved over time.

[Table: see text]

No significant financial relationships to disclose.

Bone re/modeling is more dynamic in the endothelial nitric oxide synthase(-/-) mouse

Nitric oxide is a ubiquitous estrogen-regulated signaling molecule that has been implicated in the regulation of bone maturation and remodeling. To better understand the role that bone-cell-secreted nitric oxide plays in ovariectomy-induced modifications of bone turnover, we examined the expression of endothelial NO synthase (eNOS) in bone cells and bone progenitor cells at regular intervals up to 10 wk after acute estrogen deprivation. Ovariectomy led to an anticipated initial decline in bone cell eNOS production, but surprisingly, 17 d after ovariectomy, eNOS expression by bone and marrow stromal cells dramatically rebounded and was maintained at high levels for at least 10 wk after surgery. We examined the long-term consequences of eNOS in the process of ovariectomy-induced bone loss by prospectively analyzing bone mineral density in wild-type and eNOS(-/-) mice for 10 wk after ovariectomy. Ovariectomized eNOS(-/-) mice were observed to undergo an exaggerated state of estrogen-deficiency-induced bone remodeling compared with wild-type controls, suggesting that eNOS may act to mitigate this process. Furthermore, we found that whereas bone formation in estrogen-replete wild-type mice slowed between 14 and 20 wk of age, eNOS knockout mice continued to accrue basal bone mass at a high rate and showed no sign of entering a remodeling stage. Our data suggest that eNOS may play an important role in limiting ovariectomy-induced bone remodeling as well as regulating the transition from basal modeling to remodeling.

Double-hadron leptoproduction in the nuclear medium

The first measurements of double-hadron production in deep-inelastic scattering within the nuclear medium were made with the HERMES spectrometer at DESY HERA using a 27.6 GeV positron beam. By comparing data for deuterium, nitrogen, krypton, and xenon nuclei, the influence of the nuclear medium on the ratio of double-hadron to single-hadron yields was investigated. Nuclear effects on the additional hadron are clearly observed, but with little or no difference among nitrogen, krypton, or xenon, and with smaller magnitude than effects seen on previously measured single-hadron multiplicities. The data are compared with models based on partonic energy loss or prehadronic scattering and with a model based on a purely absorptive treatment of the final-state interactions. Thus, the double-hadron ratio provides an additional tool for studying modifications of hadronization in nuclear matter.

Measurement of the tensor structure function b1 of the deuteron

The Hermes experiment has investigated the tensor spin structure of the deuteron using the 27.6 GeV/c positron beam of DESY HERA. The use of a tensor-polarized deuteron gas target with only a negligible residual vector polarization enabled the first measurement of the tensor asymmetry A(d)zz and the tensor structure function b(d)1 for average values of the Bjorken variable 0.01< <x> <0.45 and of the negative of the squared four-momentum transfer 0.5 GeV2 < <Q2> <5 GeV2. The quantities A(d)zz and b(d)1 are found to be nonzero. The rise of b(d)1 for decreasing values of x can be interpreted to originate from the same mechanism that leads to nuclear shadowing in unpolarized scattering.

Treatment of neuroendocrine cancer metastatic to the liver: the role of ablative techniques

Carcinoid tumors and islet cell neoplasms are neuroendocrine neoplasms with indolent patterns of growth and association with bizarre hormone syndromes. These tumors behave in a relatively protracted and predictable manner, which allows for multiple therapeutic options. Even in the presence of hepatic metastases, the standard of treatment for neuroendocrine malignancy is surgery, either with curative intent or for tumor cytoreduction, i.e., resection of 90% or more of the tumor volume. Image-guided ablation, as either an adjunct to surgery or a primary treatment modality, can be used to treat neuroendocrine cancer metastatic to the liver. Image-guided ablative techniques, including radiofrequency ablation, alcohol injection, and cryoablation, can be used in selected patients to debulk hepatic tumors and improve patient symptoms. Although long-term follow-up data are not available, the surgical literature indicates that significant ablative debulking may improve patient survival. In this review, we discuss metastatic neuroendocrine disease and its treatment options, especially image-guided ablative techniques.

Phase I-II trial of ONYX-015 in combination with MAP chemotherapy in patients with advanced sarcomas

ONYX-015 is a provisionally replication competent adenovirus with oncolytic activity in cells with malfunctioning p53. Sarcomas represent a rational target for this approach given the high frequency of p53 mutations (40-75%) and MDM-2 amplification (10-30%). We, therefore, undertook a phase I/II study of ONYX-015, days 1-5 every month administered intratumorally under radiographic guidance, in combination with MAP (mitomycin-C, doxorubicin, cisplatin) chemotherapy in patients with advanced sarcoma. Six patients were treated. Injected lesions included liver metastases in four patients and chest wall metastases in two patients. Sarcoma histologies were gastrointestinal stromal tumors (GIST, two patients), leiomyosarcoma (two patients), liposarcoma (one patient), and malignant peripheral nerve sheath tumor (1 patient). Dose escalation was performed from 10(9) plaque forming units (PFU)/dose (total dose of 5 x 10(9) PFU/cycle) to 10(10) PFU/dose (total dose of 5 x 10(10) PFU/cycle) without dose-limiting toxicity being encountered. Immunohistochemistry of the metastatic lesions prior to treatment showed that five out of six patients were positive for p53, while two patients also had mdm-2 overexpression. Adenoviral replication was detected in two out of six patient biopsies on day 5 of the first cycle, by in situ hybridization (ISH). Both patients were treated at the highest dose level. ONYX-015 viral DNA was detected by quantitative PCR in the plasma of 5/6 patients on day 5 of the first cycle, and up to day 12 (7 days after the last viral dose) in one patient who had extended sampling for viral kinetics performed, suggesting viral replication in sarcoma tissue. One patient with p53 mutation and MDM-2 amplification achieved a partial response to treatment that lasted 11 months. In conclusion, intratumoral administration of ONYX-015 in combination with MAP chemotherapy is well tolerated with no significant toxicity due to ONYX-015 being encountered. Detection of viral DNA in post treatment tumor specimens by ISH and detection of the ONYX-015 genome in the peripheral blood by quantitative PCR, up to 7 days after the last viral dose provide evidence for adenoviral replication. There was evidence of antitumor activity in one out of six patients. Further investigation of this approach in patients with recurrent sarcomas is warranted.

Single-spin asymmetries in semi-inclusive deep-inelastic scattering on a transversely polarized hydrogen target

Single-spin asymmetries for semi-inclusive electroproduction of charged pions in deep-inelastic scattering of positrons are measured for the first time with transverse target polarization. The asymmetry depends on the azimuthal angles of both the pion (phi) and the target spin axis (phi(S)) about the virtual-photon direction and relative to the lepton scattering plane. The extracted Fourier component sin((phi+phi(S))(pi)(UT) is a signal of the previously unmeasured quark transversity distribution, in conjunction with the Collins fragmentation function, also unknown. The component sin((phi-phi(S)(pi)(UT) arises from a correlation between the transverse polarization of the target nucleon and the intrinsic transverse momentum of quarks, as represented by the previously unmeasured Sivers distribution function. Evidence for both signals is observed, but the Sivers asymmetry may be affected by exclusive vector meson production.

Prostate carcinoma cells that have resided in bone have an upregulated IGF-I axis

BACKGROUND

Prostate cancer (PC) has a propensity to metastasize to the skeleton, inducing an osteoblastic response in the host. Recent epidemiological studies have suggested that circulating IGF-I may be important for both the pathogenesis and dissemination of PC. We have postulated that tumor secreted IGF-I in conjunction with endogenous IGF-I contributes to the osteoblastic phenotype characteristic of metastatic PC.

METHODS

To test this thesis we studied the established LNCaP PC progression model consisting of three genetically related human PC cell lines.

RESULTS

Using RIA, we found serum-free conditioned media (CM) of LNCaP and C4-2 had no measurable IGF-I, whereas IGF-I was easily detected in CM from C4-2B cells at 24 hr (i.e., 1.8 +/- 0.53 ng/mg cell protein). Real-time PCR of IGF-I mRNA showed that C4-2B expressed 100-fold more IGF-I mRNA than LNCaP cells. In addition, C4-2B expression of IGF-I mRNA was substantially increased in the presence of exogenous IGF-I to nearly twofold. While IGFBP-3 and IGFBP-1 were not detectable in the CM of any PC line, all cells secreted IGFBP-2. C4-2B cells produced 40% more IGFBP-2 than LNCaP or C4-2 cells (C4-2B at 167 +/- 43 ng/mg cell protein). RANKL, a product of bone stromal cells, was also differentially expressed: LNCaP had threefold higher RANKL mRNA compared to C4-2 and C4-2B and at least equivalent protein expression.

CONCLUSIONS

Our results suggest that PC cells that have metastasized to bone have an upregulated IGF-I regulatory system. This suggests an activated IGF-I axis contributes to the host-PC interaction in promoting osteoblastic metastases.

Mesenchymal stem cells: aesthetic applications

Adult stem cells may have significant aesthetic surgery applications. Their replicative capacity and plasticity may be useful in engineering autologous grafts for soft tissue and facial skeletal augmentation. Another possibility is that increasing the concentration of mesenchymal stem cells in the facial soft tissue at regular intervals during adulthood will maintain volume and elasticity. (Aesthetic Surg J 2003;23:504-506.).

A phase I study of sequential irinotecan and 5-fluorouracil/leucovorin

BACKGROUND

Irinotecan (CPT-11) and 5-fluorouracil (5-FU)/leucovorin are active agents in colorectal cancer. A sequence-dependent synergism of SN-38 followed by 5-FU/leucovorin in vitro led us to conduct a phase I trial of CPT-11 followed by 5-FU/leucovorin to determine the maximum tolerated dose (MTD) and toxicities of this regimen and to obtain preliminary indications of its activity in patients with advanced solid tumors.

PATIENTS AND METHODS

Fifty-six patients were enrolled in sequential cohorts to receive escalating doses of CPT-11 (90 min infusion) on day 1, followed by leucovorin 20 mg/m(2) (intravenous push) and 5-FU (90 min infusion) on days 2-5 of each 21-day cycle.

RESULTS

A total of 347 treatment cycles (median 4, range 1-25) were administered. Dose-limiting toxicities were diarrhea, neutropenia and fatigue. Nine patients with colorectal cancer and one with gastric cancer had partial or minor responses. Eight of the 10 had prior chemotherapy.

CONCLUSIONS

CPT-11 and 5-FU/leucovorin, as constituents of this novel mechanism-based schedule, have promising activity in patients who have received prior chemotherapy. The recommended phase II/III starting doses are CPT-11 275 mg/m(2) over 90 min on day 1, and 5-FU 400 mg/m(2) plus leucovorin 20 mg/m(2) on days 2-5 every 21 days. This combination can be administered safely to this schedule if there is strict adherence to the 90 min infusion time for both CPT-11 and 5-FU.

IGF-I regulates osteoprotegerin (OPG) and receptor activator of nuclear factor-kappaB ligand in vitro and OPG in vivo

IGF-I, a ubiquitous polypeptide, plays a key role in longitudinal bone growth and acquisition. The most predominant effect of skeletal IGF-I is acceleration of the differentiation program for osteoblasts. However, in vivo studies using recombinant human (rh) IGF-I and/or rhGH have demonstrated stimulation of both bone formation and resorption, thereby potentially limiting the usefulness of these peptides in the treatment of osteoporosis. In this study, we hypothesized that IGF-I modulates bone resorption by regulating expression of osteoprotegerin (OPG) and receptor activator of nuclear factor-kappaB (RANK) ligand (RANKL) in bone cells. Using Northern analysis in ST2 cells, we found that human IGF-I suppressed OPG mRNA in a time- and dose-dependent manner: 100 micro g/LIGF-I (13 nM) decreased OPG expression by 37.0 +/- 1.8% (P < 0.002). The half maximal inhibitory dose of IGF-I was reached at 50 micro g/liter ( approximately 6.5 nM) with no effect of IGF-I on OPG message stability. Conditioned media from ST2 cells confirmed that IGF-I decreased secreted OPG, reducing levels by 42%, from 12.1-7 ng/ml at 48 h (P < 0.05). Similarly, IGF-I at 100 micro g/liter (13 nM) increased RANKL mRNA expression to 353 +/- 74% above untreated cells as assessed by real-time PCR. In vivo, low doses of rhGH when administered to elderly postmenopausal women only modestly raised serum IGF-I (to concentrations of 18-26 nM) and did not affect circulating OPG concentrations; however, administration of rhIGF-I (30 micro g/kg.d) for 1 yr to older women resulted in a significant increase in serum IGF-I (to concentrations of 39-45 nM) and a 20% reduction in serum OPG (P < 0.05). In summary, we conclude that IGF-I in a dose- and time-dependent manner regulates OPG and RANKL in vitro and in vivo. These data suggest IGF-I may act as a coupling factor in bone remodeling by activating both bone formation and bone resorption; the latter effect appears to be mediated through the OPG/RANKL system in bone.