Syndrome of inappropriate antidiuresis in small-cell lung cancer. Classification and effect of tumor regression

Patients with small-cell lung cancer and hyponatremia were examined for the syndrome of inappropriate antidiuresis (SIAD). A comparison was made between the definition based on hyponatremia, serum hypoosmolality and urine hyperosmolality (classic SIAD, 12 patients) and a definition based on measurement of plasma ADH concentration by radioimmunoassay (RIA-SIAD, nine patients) and patients without SIAD (eight patients). A standard water load test was performed as a reference before initiation of cytostatic treatment. All tests were repeated if remission of the malignant disease occurred. RIA-SIAD patients were a subgroup of classic SIAD patients, with more pronounced homeostatic abnormalities. Biochemical abnormalities were reduced after tumor regression but a completely normal renal water handling was achieved in only few patients, even when complete remission of the tumor was achieved, presumably due to the persistence of subclinical disease. However, an effect of other yet unknown factors might be of influence.

Anti-tumor activity of recombinant human Interleukin-21 (rIL-21): Preliminary data from a phase 2a study in patients with stage IV malignant melanoma (MM) without prior treatment

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Background: rIL-21 is a pleiotropic class I cytokine that activates CD8+ T cells and NK cells. The safety and pharmacologic profile of rIL-21 was characterized in two phase 1 dose escalation studies including patients with MM, performed in Australia and the US, respectively. Two dosing schedules were tested: “5+9” (5 days of dosing followed by 9 days of rest) and “3/wk” (dosing 3 times per week for 6 weeks). The maximum tolerated dose (MTD) was determined to be 30 μg/kg for both dosing regimens and two complete remissions (at the 30 μg/kg dose level) were observed in the MM patients. A phase 2a study was initiated to estimate the preliminary efficacy of rIL-21 in patients with advanced MM. Methods: The phase 2a study design is an open-label, two-stage trial. Primary objective: antitumor efficacy as determined by response rate. Secondary objectives: safety, effects on blood biomarkers, and measurement of anti-rIL-21 antibodies. Eligible patients had unresectable MM with measurable disease, no prior systemic therapy (adjuvant interferon was permitted), adequate major organ function, good performance status, no brain metastases, and no evidence of significant autoimmune disease. rIL-21 was administered by i.v. bolus injection using the “5+9” regimen for 6 weeks (= three cycles) at 30 μg/kg dose level. Results: At the time of writing (January 2007), all 14 patients have entered the first stage of the phase 2a study and currently seven patients are evaluable for response after completion of 3 treatment cycles (6 weeks). One patient had a complete remission, five patients had stable disease, and one patient had progressive disease. So far, six patients have gone on to receive further treatment with rIL-21. Similar to the phase 1 experience, treatment with rIL-21demonstrated an acceptable safety profile. Updated interim study results, including response data, will be presented. Conclusions: rIL-21 administered at 30 μg/kg/day using the “5+9” regimen is well tolerated by patients with MM. Preliminary evidence of clinical response has been observed and the second stage of the two-stage phase 2a study has opened for accrual.

[Table: see text]

Overexpression of thrombospondin-1 reduces growth and vascular index but not perfusion in glioblastoma

Little is known about the effects of antiangiogenic therapy on perfusion of human tumors and the mechanisms by which tumors can adapt to these treatments and recur. Here, we examined the effects of serial passaging of LN-229 human glioma xenografts overexpressing thrombospondin (TSP)-1 on tumor growth, vascularity, and perfusion. Persistence of TSP-1 overexpression was confirmed after three serial s.c. passages of small xenografted tumor blocks of cells stably transfected with TSP-1 cDNA (clones C9 and E7) or vector controls (pooled clones A7-A9) in immunodeficient nu/nu mice. The tumor vascularity was estimated by noninvasive near infrared spectroscopy measuring blood volume at 800 +/- 10 nm and by histological vessel scores in CD31-immunostained cryosections. The tumor perfusion was assessed by noninvasive laser Doppler flowmetry. Overexpression of TSP-1 significantly inhibited tumor growth. In size-matched tumors (approximately 300 mm(3)), the blood volume and the histological vessel scores were lower in the TSP-1-transfected tumors than in controls, and this effect was more pronounced in tumors derived from the clone with the highest TSP-1 expression (clone E9). Despite this clear reduction in tumor vascularity, the tumor perfusion was the same in TSP-1-transfected tumors and controls. This study shows that TSP-1 overexpression slows glioma growth in vivo but does not prevent it from reaching a large size (300 mm(3)). Whereas a clear reduction in blood volume during tumor growth and a reduced vascular index at sacrifice are observed in TSP-1-transfected tumors, this did not affect perfusion when size-matched comparisons were performed. Given the increased time needed to reach equal size, it indicates that a fixed rate of perfusion must be maintained in the tumor to allow for growth. Elucidation of the mechanisms that allow this to happen has important consequences for the understanding of tumor recurrence after antiangiogenic therapy.

Quantitative estimates of vascularity in solid tumors by non-invasive near-infrared spectroscopy

We examined the relationship between non-invasive estimates of the tumor hemoglobin concentration by near-infrared spectroscopy (NIRS) and histological scores of tumor vascularity by Chalkley counts in seven tumor lines in nude mice [malignant gliomas: U87, U118, U373; small cell lung cancers (SCLC): 54A, 54B, DMS79; prostate cancer: MatLyLu (MLL)]. We also evaluated the effect of continuous anti-angiogenic treatment with TNP-470 on tumor hemoglobin concentration and tumor vascularity in U87 and MLL tumors. Non-invasive NIRS recordings were performed with a custom-built flash near-infrared spectrometer using light guide-coupled reflectance measurements at 800+/-10 nm. Chalkley counts were obtained from CD31-immunostained cryosections. The NIRS recordings in arbitrary absorbance units increased with tumor size in the individual tumors until a plateau was reached at approximately 150 mm(3). This plateau was relatively tumor line-specific. NIRS recordings at the plateau phase were strongly correlated (P<.001, n=71) to the histological vessel score (Chalkley count) of the same individual tumors excised immediately after the NIRS was performed. Non-invasive NIRS recordings of the highly vascularized gliomas (U87, U118, and U373) plus the MatLyLu tumor line were significantly higher than the three less vascularized SCLC tumor lines (P<.001). Continuous treatment with the anti-angiogenic compound TNP-470, an endothelial cell inhibitor, significantly retarded tumor growth in both U87 and MLL tumors, but all tumors eventually grew. When comparing treated and untreated tumors of similar size, both NIRS recordings and Chalkley counts were significantly lower in TNP-470-treated tumors (P<.05). In conclusion, the NIRS technique provides a non-invasive measure of the degree of vascularization in untreated tumors and the NIRS technique can measure modifications in tumor vascularization by anti-angiogenic therapy.

Quantitative estimates of angiogenic and anti-angiogenic activity by laser Doppler flowmetry (LDF) and near infra-red spectroscopy (NIRS)

The use of laser Doppler flowmetry (LDF) and near-infra-red spectroscopy (NIRS) for non-invasive in vivo measurements of angiogenic and anti-angiogenic activity in nude mice was evaluated. Angiogenic foci were induced in the skin by implantation of slow release pellets containing 200 ng basic fibroblast growth factor (bFGF). LDF and NIRS recordings from induced foci were significantly higher than placebo implants (P<0.05) and controls (P<0.001), proving that LDF and NIRS provide measures of angiogenic activity. Correspondingly, by these methods, an anti-angiogenic activity was significantly demonstrated in bFGF-stimulated animals treated with either the specific anti-angiogenic compound TNP-470 (P<0.05) or the anti-inflammatory agent dexamethasone (P<0.001). We conclude that LDF and NIRS, alone or in combination, are useful non-invasive tools for early evaluation of angiogenic and anti-angiogenic activity in vivo.

Coregulation of glucose uptake and vascular endothelial growth factor (VEGF) in two small-cell lung cancer (SCLC) sublines in vivo and in vitro

We examined the relationship between (18)F- labeled 2-fluro-2-deoxy-d-glucose (FDG) uptake, and expression of glucose transporters (GLUTs) in two human small-cell lung cancer (SCLC) lines CPH 54A and CPH 54B. Changes in the expression of GLUTs and vascular endothelial growth factor (VEGF) during 12-, 18-, and 24 hours of severe hypoxia in vivo (xenografts) and in vitro (cell cultures) were recorded for both tumor lines. The two SCLC lines are subpopulations of the same patient tumor. In spite of their common genomic origin they represent consistently different metabolic and microenvironmental phenotypes as well as treatment sensitivities. There were higher levels of Glut-1 protein in 54B and a correspondingly higher FDG uptake in this tumor line (P<.001). During hypoxia a significant upregulation of in VEGF mRNA, GLUT-1 mRNA, and Glut-1 and -3 protein occurred with a distinctly different time course in the two cell lines. A similar co-upregulation of GLUT and VEGF was seen in hypoxic tumors of both lines. There were no significant changes of HIF-1alpha mRNA during hypoxia in either of the cell lines. A more detailed understanding of such correlations between glucose metabolism, angiogenesis, and microenvironmental phenotype of tumors, by positron emission tomography (PET) and molecular techniques might further sophisticate our interpretation of glycolytic predominance in tumors as seen by 18FFDG PET.

Relationship between vessel density and expression of vascular endothelial growth factor and basic fibroblast growth factor in small cell lung cancer in vivo and in vitro

In 21 human small cell lung cancer (SCLC) cell lines, we determined the expression of mRNA and secreted protein levels of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). The VEGF expression was highly variable between cell lines, with a > 100-fold variation, under identical in vitro conditions. The bFGF expression in cell lines was generally very low. Nine of the cell lines were further analyzed during growth as solid tumor xenografts in nude mice (in vivo). A more uniform VEGF protein expression was present in vivo. Compared with the variable in vitro expression, VEGF was relatively up-regulated in the tumor lines CPH 54A and CPH 54B and down-regulated in GLC 3. One line, DMS 79, had a high VEGF expression in vivo as well as in vitro. The vessel density was determined by Chalkley point counting on CD31 immunostained cryosections of tumors of each of the nine SCLC lines. We found a strong positive correlation between vessel density and tissue VEGF protein expression (r(s) = 0.75; P = 0.02) and a comparatively strong negative correlation (r(s) = -0.80; P = 0.01) between vessel density and tissue bFGF expression. No significant correlation was present between vessel density and in vitro VEGF expression. We conclude that VEGF and bFGF expression is dependent on microenvironmental conditions, as well as cell line-specific factors, and that a strong positive correlation exists between in vivo VEGF expression and vessel density, whereas high tissue levels of bFGF are not correlated with higher vessel densities in SCLC xenografts.

Therapeutic synergy of TNP-470 and ionizing radiation: effects on tumor growth, vessel morphology, and angiogenesis in human glioblastoma multiforme xenografts

We examined the effect on tumor growth, vessel morphology, and expression of angiogenic factors of combining radiotherapy and antiangiogenesis in the human glioblastoma line U87 grown in the flank or intracranially in the nude mouse. The antiangiogenic agent TNP-470 was given 6.7 mg/kg s.c. daily on day 1-7 starting 1 week after transplantation. Irradiation (IR), 10 Gy x 1, was administered on day 7. A series of tumors were excised 8 and 48 h after the end of treatment. The vascular morphology was evaluated in CD31 immunostained cryosections and by electron microscopy, and the pattern of expression of angiogenic factors (mRNA and protein) was quantitatively analyzed by phosphorimaging of Northern blots and Western blots. Significant inhibition of s.c. flank tumor growth relative to untreated controls was achieved by monotherapy with both TNP-470 (P < 0.001) and IR (P < 0.001). A significant enhancement of this effect was obtained by combining TNP-470 and IR (P < 0.05). We saw no effect of TNP-470 either alone or in addition to the effect of IR on the survival of mice with intracranial tumors. CD31 immunostaining of s.c. tumors showed acute endothelial swelling and luminal protrusion in irradiated tumor vessels but never in tumors pretreated with TNP-470, and not in the untreated controls. The vessel density (Chalkley point counts) was unchanged by TNP-470 therapy. In the TNP-470-treated tumors, we observed a distinct broadening of the endothelial basement membrane by an approximately 400-700-nm-thick electron-dense yet uncharacterized fibrillar material. TNP-470 treated tumors +/- IR also had a significantly increased mRNA expression of angiopoietin-1, whereas angiopoietin-2, vascular endothelial growth factor and basic fibroblast growth factor mRNA were unchanged by the treatments. In conclusion, TNP-470 significantly enhanced the tumor effect of ionizing IR, and our findings strongly indicate that acute microvascular damage after IR is effectively prevented by concurrent TNP-470 treatment. A significant up-regulation of angiopoietin-1 seems to play a role in this protective mechanism, which as yet is not fully elucidated.

Prophylactic cranial irradiation for patients with small-cell lung cancer in complete remission. Prophylactic Cranial Irradiation Overview Collaborative Group

BACKGROUND

Prophylactic cranial irradiation reduces the incidence of brain metastasis in patients with small-cell lung cancer. Whether this treatment, when given to patients in complete remission, improves survival is not known. We performed a meta-analysis to determine whether prophylactic cranial irradiation prolongs survival.

METHODS

We analyzed individual data on 987 patients with small-cell lung cancer in complete remission who took part in seven trials that compared prophylactic cranial irradiation with no prophylactic cranial irradiation. The main end point was survival.

RESULTS

The relative risk of death in the treatment group as compared with the control group was 0.84 (95 percent confidence interval, 0.73 to 0.97; P= 0.01), which corresponds to a 5.4 percent increase in the rate of survival at three years (15.3 percent in the control group vs. 20.7 percent in the treatment group). Prophylactic cranial irradiation also increased the rate of disease-free survival (relative risk of recurrence or death, 0.75; 95 percent confidence interval, 0.65 to 0.86; P<0.001) and decreased the cumulative incidence of brain metastasis (relative risk, 0.46; 95 percent confidence interval, 0.38 to 0.57; P<0.001). Larger doses of radiation led to greater decreases in the risk of brain metastasis, according to an analysis of four total doses (8 Gy, 24 to 25 Gy, 30 Gy, and 36 to 40 Gy) (P for trend=0.02), but the effect on survival did not differ significantly according to the dose. We also identified a trend (P=0.01) toward a decrease in the risk of brain metastasis with earlier administration of cranial irradiation after the initiation of induction chemotherapy.

CONCLUSIONS

Prophylactic cranial irradiation improves both overall survival and disease-free survival among patients with small-cell lung cancer in complete remission.

Time until initiation of tumor growth is an effective measure of the anti-angiogenic effect of TNP-470 on human glioblastoma in nude mice

We examined the effect of the anti-angiogenic compound TNP-470 on early tumor growth characteristics following subcutaneous implantation of 1 mm3 tissue blocks of human glioblastoma U87, in nude mice. The mice received daily injections with TNP-470, 7 mg/kg, from one day before until either 3, 7, 11, or 15 days after inoculation. The time from inoculation until initiation of exponential tumor growth was determined along with the post-therapeutic growth delay and the initial tumor doubling time (TD) for each individual tumor (n=103) on the basis of tumor volume growth curves. We found that: i) the onset of growth of U87 xenografts was effectively inhibited by concurrent treatment with TNP-470 beyond the first three days after inoculation, ii) this effect was fully reversible upon termination of therapy, and iii) the post-therapeutic growth delay was independent of the accumulated dose. These findings demonstrate that the in vivo effect of TNP-470 on tumor growth is tumor inhibitory rather than cytotoxic. The lack of effect of the anti-angiogenic compound, TNP-470, in the early 3-day schedule is consistent with the existence of an early avascular phase which precede the angiogenesis-dependent tumor growth.

Treatment of newly diagnosed glioblastoma multiforme with carmustine, cisplatin and etoposide followed by radiotherapy. A phase II study

A meta-analysis and several studies of patients with grade III and IV gliomas have indicated that the addition of nitrosurea based chemotherapy to surgery and radiation may improve survival. We performed a phase II study of pre-irradiative chemotherapy with BCNU, cisplatin and etoposide. This implies a short total treatment duration and a reliable response evaluation. The treatment schedule was three cycles of BCNU 200 mg/m2 i.v. on day 1, cisplatin 20 mg/m2 i.v. on day 1-5 and etoposide (VP-16) 100 mg/m2 i.v. on day 1-5, given every five weeks and followed by localized radiation, 60 Gy in 30 fractions. Twenty-nine patients with newly diagnosed glioblastoma multiforme (GBM), mean age 50 (27-66) and performance status (PS) 0-2 were included. Using the Macdonald criteria 33% had partial remission (PR), 41% stable disease (SD) and 26% progressive disease (PD) after chemotherapy. After additional radiation 44% had PR, 37% SD and 19% PD. Non-hematological toxicity and leukopenia was mild, but thrombocytopenia (TP) frequent. Grade III and IV TP occurred in 25% and 57% respectively, and grade III bleeding in 45%. No severe or fatal complications was seen. Median time to progression (TTP) was 7.6 months (6.0-9.1) and median survival was 11.4 months (10.1-12.7). We conclude that this regimen is effective and feasible in patients with GBM. The short course pre-irradiatory chemotherapy may be less cumbersome than adjuvant chemotherapy and the regimen may be even more active in grade III gliomas.

The rat Subcutaneous Air Sac model: a quantitative assay of antiangiogenesis in induced vessels

A new in vivo experimental model--the Subcutaneous Air Sac (SAS) model-has recently been presented to replace a previous in vivo rabbit cornea assay where neovascularisation was induced by chemical injury of the cornea or by implantation of tumour cells intracorneally, a methodology which is believed to cause severe pain to the animals. In the SAS model, an air sac is induced by injection of air subcutaneously on the back of the animal. After 10-14 days the air sac appears as an almost transparent avascular membrane in which induction of new vessels can be studied. We present recent developments of this technique: In the SAS-tumour technique, vascular endothelial growth factor-producing tumour cells are inoculated subcutaneously directly on the membrane, and the formation of new vessels is measured 8 days later. In the SAS-pellet technique, slow-release pellets containing angiogenic factors, basic fibroblast growth factor or vascular endothelial growth factor are implanted on the subcutaneous membrane by a simple operation. The formation of new vessels is measured 10 days later. The ability of the SAS-tumour- and SAS-pellet techniques to detect an antiangiogenic effect of a systemically administered compound was investigated using the fumagillin analogue TNP-470 (o-chloroacetyl-carbamoyl)-fumagillol) as a positive control given subcutaneously for 7 and 9 days, respectively. At a dose of 10 mg TNP-470/kg/day the angiogenesis was reduced by approximately 70% in the SAS-tumour technique and by 40-60% in the SAS-pellet technique. The animals were unaffected by the SAS methodology. The SAS-tumour and SAS-pellet models are considered complementary and make use of simple and almost similar techniques which facilitate the evaluation.

Effect of radiation therapy on small-cell lung cancer is reduced by ubiquinone intake

The effect of oral ubiquinone (Q10) intake on the in vivo response of tumors to single dose radiotherapy was examined. The human small-cell lung cancer (SCLC) line CPH 054A, which is sensitive to relatively low doses of X-radiation, was grown as subcutaneous transplants in the flanks of nude nu/nu mice. When macroscopical growth was established, groups of mice received either 10, 20 or 40 mg/kg Q10 in 30 mL soy oil intragastrically daily on 4 consecutive days. Controls received either 30 mL of pure soy oil or nothing. Three h after the last dose half of the tumors in each group received a single radiation dose of 5 Gy, using a 300 kV therapeutic unit. The macroscopic growth pre- and posttreatment was analyzed according to a transformed Gompertz algorithm using the software program GROWTH. Treatment with Q10 or soy oil alone had no effect on tumor growth compared with untreated controls. Groups of tumors that received Q10 and radiotherapy had a significantly lower specific growth delay (SGD) than the radiotherapy-only groups. This effect was significant at 40 mg/kg and borderline at 20 mg/kg, whereas at 10 mg/kg no radioprotection was seen. We conclude that systemic Q10 reduces the response to single dose tumor irradiation inxenotransplanted human SCLC tumors.

Tumor angiogenesis--a new therapeutic target in gliomas

Tumor growth is critically dependent on angiogenesis, which is sprouting of new vessels from pre-existing vasculature. This process is regulated by inducers and inhibitors released from tumor cells, endothelial cells, and macrophages. Brain tumors, especially glioblastoma multiforme, have significant angiogenic activity primarily by the expression of the angiogenic factor VEGF Anti-angiogenic therapy represents a new promising therapeutic modality in solid tumors. Several agents are currently under evaluation in clinical trials. The present review describes the principal inducers and inhibitors of angiogenesis in tumors and summarizes what is known about their mechanisms of action in relation to CNS tumors. Potential areas for clinical use are also discussed.

Superiority of cisplatin or carboplatin in combination with teniposide and vincristine in the induction chemotherapy of small-cell lung cancer. A randomized trial with 5 years follow up

PURPOSE

The introduction of platinum compounds and epipodophyllotoxins in combination with vincristine as induction chemotherapy in small-cell lung cancer (SCLC) was investigated in order to: (1) compare the efficacy of cisplatin with that of carboplatin in combination with teniposide and vincristine as inducers of remission over three cycles; (2) compare the toxicity pattern of carboplatin and of cisplatin when given in combination regimens; and (3) compare a chemotherapeutic regimen consisting of three alternating combinations with that of regimens consisting of four alternating combinations.

PATIENTS AND METHODS

From November 1985 to September 1991, 484 consecutive, previously untreated patients with SCLC, performance status 0-4, entered a three armed randomized trial with three cycles of cisplatin (arm I) or carboplatin (arm II) in combination with teniposide and vincristine alternating with three treatment blocks of cyclophosphamide, etoposide, lomustine and vincristine (block A), doxorubicin and vincristine (block B) and cisplatin, hexamethylmelamine and vindesine (block C) versus alternating treatment with block A, B and C (arm III).

RESULTS

No difference in efficacy or toxicity was found between cisplatin and carboplatin at the present dosages. Induction chemotherapy with teniposide plus cisplatin or carboplatin did not result in higher complete response rates (objective response rates 63%, 72% and 65%, respectively) or in significantly greater toxicity, but overall survival was superior compared with the arm III (log-rank test, P = 0.02). The median survival difference was 7 weeks, and two year survival 15% versus 9%. The Cox regression analysis identified the arm III, poor performance status and elevated LDH as factors with statistically significant negative impact on survival.

CONCLUSION

Cisplatin and carboplatin produced similar response and survival rates and similar toxicity. Induction with platinum and epipodophyllotoxins did not improve objective response rates, but significantly improved survival without increasing the toxicity.

Intratumor pharmacokinetics, flow resistance, and metabolism during gemcitabine infusion in ex vivo perfused human small cell lung cancer

The relationship between tumor physiology and the pharmacokinetics of 2',2' difluorodeoxycytidine [gemcitabine (dFdC)] in ex vivo perfused human small cell lung cancer was examined. Two small cell lung cancer sublines, 54A and 54B, with known in vivo sensitivity to dFdC, were grown as tissue-isolated tumors in athymic mice and perfused ex vivo with or without 20-40 micrometer dFdC. Arteriovenous differences in gases, pH, and metabolites were determined before and during drug infusion. The geometric flow resistance (FR) of individual tumors was calculated, and dFdC and its inactive metabolite 2',2' difluorodeoxyuridine were determined by high-performance liquid chromatography of consecutive samples from the output line. Both tumors had prominent lactate production concurrent with a significant O2 consumption. The arteriovenous pH drop was approximately 0.3 in both tumor lines. Significant metabolic differences between 54A and 54B tumors were found that elucidated previously described differences further. Pharmacokinetic analysis showed that the initial tumor uptake of dFdC was flow limited, and a significant inverse correlation between the geometric FR and initial drug uptake was found. The rate constant for recovery of the drug in the tumor outflow was greater in 54B tumors (P < 0.05), and the geometric FR was greater in 54A tumors (P < 0.01). The drug conversion rate was independent of physiological parameters. Attempts to modify the delivery of dFdC should be directed at the tumor blood flow distribution. More generally, our experimental model provides useful new insight into metabolism and intratumor pharmacokinetics of chemotherapeutic agents in solid tumors.

Growth inhibition in response to estrogen withdrawal and tamoxifen therapy of human breast cancer xenografts evaluated by in vivo 31P magnetic resonance spectroscopy, creatine kinase activity, and apoptotic index

Estrogen withdrawal versus tamoxifen (TAM) treatment was compared in two human breast cancer xenografts, the estrogen-dependent ZR75-1 and its estrogen-independent subline ZR75/LCC-3. The following parameters were determined: tumor growth, NTP:P(i) by 31P magnetic resonance spectroscopy, apoptotic index, and creatine kinase (CK) activity. Tumors of each line were grown in ovariectomized nude mice during stimulation from a s.c. 17 beta-estradiol pellet. At a tumor size of approximately 350 mm3, the pellet was removed from one-half of the animals. The remaining one-half served as controls. In parallel experiments, injections of TAM were initiated instead of estrogen withdrawal. Estrogen withdrawal as well as TAM induced growth inhibition of ZR75-1 tumors, whereas ZR75/LCC-3 was resistant to both types of therapy. Growth inhibition of ZR75-1 by estrogen withdrawal, but not by TAM, was accompanied by an 80% increase of the NTP:P(i) ratio (P < 0.01) and a significantly decreased cytosolic CK activity (P < 0.01). No significant change in pH was observed. These changes seemed not to be related to changes in apoptotic index. None of the described changes occurred in ZR75/LCC-3. The present data indicate: (a) ZR75-1 and ZR75/LCC-3 xenografts respond differently to estrogen withdrawal and TAM with regard to growth inhibition, 31P magnetic resonance spectroscopy, and CK activity; (b) estrogen withdrawal, but not TAM, induced a decrease in the CK activity of estrogen-dependent tumor tissue, and (c) increased apoptosis did not explain the growth inhibition and the increase in NTP:P(i) induced by estrogen withdrawal. The results indicate other growth inhibitory mechanisms of TAM in addition to competitive inhibition of the estrogen receptor.

Prophylactic cranial irradiation in small cell lung cancer--an update

The role of prophylactic cranial irradiation (PCI) in the management of patients with small cell lung cancer is reviewed, with emphasis on 11 randomised trials. Several interpretive and methodological problems related to PCI investigations are identified, and it is argued that given the current data PCI should be considered as an optional treatment component in CR patients, that these authors do not recommend, while other investigators do.

Effect of estrogen withdrawal on energy-rich phosphates and prediction of estrogen dependence monitored by in vivo 31P magnetic resonance spectroscopy of four human breast cancer xenografts

The effect of estrogen withdrawal on energy metabolism was studied in four human breast cancer xenografts: the estrogen-dependent MCF-7 and ZR75-1 and the estrogen-independent ZR75/LCC-3 and MDA-MB-231. The tumors were grown in ovariectomized nude mice with a s.c. implanted estrogen pellet. After Gompertzian growth was verified, the estrogen pellet was removed from half of the animals. In vivo 31P magnetic resonance spectroscopy of the tumors was performed 1 day before and on days 2, 6, and 14 after estrogen removal. Estrogen withdrawal induced a significant increase in the nucleoside triphosphate:Pi ratio in the two estrogen-dependent xenografts, whereas this ratio remained unchanged in the estrogen-independent tumors. In ZR75/LCC-3 tumors a slight decrease in nucleoside triphosphate:Pi was observed following onset of estrogen stimulation after initial growth without estrogen. Extracts of freeze-clamped tumors prepared 14 days after estrogen removal were analyzed for ATP and phosphocreatine content. Our findings suggest a correlation between estrogen withdrawal and the steady-state concentrations of ATP, phosphocreatine, and Pi in human breast cancer xenografts. Discrimination analysis of the pretherapeutic spectra enabled us to identify the tumor line and the estrogen dependence of the tumors in 80-90% of all cases.

Spatial heterogeneity in tumor perfusion measured with functional computed tomography at 0.05 microliter resolution

High speed (200 ms temporal resolution) functional computed tomography was used to demonstrate tumor vascular heterogeneity with 0.05 microliter spatial resolution. Vascular topologies were investigated in 2 human small cell lung cancer lines implanted either s.c. or as a tissue isolated preparation in immunocompromised mice. Peripheral versus central vascular topology was identified in the s.c. and tissue-isolated preparations, respectively. Pharmacokinetic analysis demonstrated that tumor physiology was influenced by cell line (P = 0.016) and not by location (P > 0.6). This new technique has the potential to characterize individual tumors in patients with minimal invasiveness, permitting more detailed prognosis and management.

Tissue-isolated human tumor xenografts in athymic nude mice

An ex vivo perfused solid tumor preparation provides control over the physiological, biochemical, and pharmacological composition of the arterial input and easy access to the venous output. This is advantageous for studies of transport and metabolism in solid tumors. Here we present a tissue-isolated tumor preparation adapted to the nude mouse, allowing ex vivo perfusion of human tumor xenografts. Previously, such preparations have only been developed in rats, to study primarily rodent tumors. In the present study this new tumor preparation is physiologically characterized in comparison with subcutaneously transplanted tumors in nude mice using the human colon adenocarcinoma LS174T.

Comparison of clinical neurological function and CT response during chemotherapy for initial brain metastases from small cell lung cancer

We compared the clinical neurological and functional response with changes in CT during systemic combination chemotherapy in 20 patients with initial brain metastases from small cell lung cancer (SCLC). Seven patients died within four weeks from start of chemotherapy, leaving 13 patients for evaluation of treatment response. Eight patients improved to or maintained a high neurological score, meaning no or insignificant neurological deficits or disability. Three patients had a stable neurological score, and 2 patients deteriorated. The median duration of the clinical response was 20 weeks. Based on changes in CT four patients had complete remission, six had partial remission, and two showed no change. One patient had a rapid deterioration of her clinical condition and died without CT control. Five patients with late CNS relapse were treated with second-line cranial irradiation inducing clinical improvement in three. Median survival was 11 weeks, and in assessable patients, excluding early deaths, 28 weeks. In conclusion initial brain metastases respond to systemic chemotherapy as readily as extracranial locations of SCLC, and in many patients prolonged neurological and CT remission can be achieved.

Should current management of small cell lung cancer include prophylactic cranial irradiation?

The literature on the use of prophylactic cranial irradiation (PCI) in the management of small cell lung cancer (SCLC) is reviewed, focusing on the ten randomized trials published until 1991. Eight out of ten randomized trials have shown some reduction in the frequency of CNS relapse in patients who have had PCI, whereas none have shown any survival benefit associated with PCI. Current data indicate that survival is exclusively dependent on an effect of PCI in only a very limited subgroup of patients (10% of complete responders). It is generally agreed that PCI is not justified in patients who are not in CR, but even in this situation it is unknown whether PCI is necessary. The current therapeutic potentials seem to leave comparable fractions of patients without sufficient palliation of their symptomatic brain metastases regardless of whether or not PCI is given. Data from sufficiently large randomized trials have to be matured and analyzed, before the role of PCI in SCLC can be defined.

Dexamethasone reduces the interstitial fluid pressure in a human colon adenocarcinoma xenograft

The effect of dexamethasone on interstitial hypertension was evaluated in a human colonic adenocarcinoma. Two weeks after transplantation of the tumor line LS174T into SCID mice, recipients with tumors > 8.5 mm in diameter received one daily injection i.p. on days 1-4, at five different doses in the range of 0.3-30 mg/kg. Controls received saline. The interstitial fluid pressure (IFP) was determined in all tumors pretherapeutically on days 1, 4, and 7. A total of 68 tumors were examined, and in an additional group of 22 mice, the effect of 4-day dexamethasone therapy on blood pressure was evaluated. In the 3-, 10-, and 30-mg/kg dose groups a significant reduction in IFP was found, comparing treated versus controls and individual measurements from day 1 versus day 4. No effects were observed on day 7. A marginal effect was observed after 1.0 mg/kg, whereas 0.3 mg/kg did not affect the IFP. The systemic blood pressure was slightly increased by the dexamethasone therapy, and no treatment related changes in tumor sizes were observed. Our findings indicate that the reversible decrease in tumor IFP by dexamethasone is an effect of a reduced microvascular permeability and vascular hydraulic conductivity in the tumors.

Prospective evaluation of the effect on initial brain metastases from small cell lung cancer of platinum-etoposide based induction chemotherapy followed by an alternating multidrug regimen

BACKGROUND

During the 1980s reports describing the effect of systemic chemotherapy on brain metastases from chemosensitive tumours emerged, including a few retrospective reports on small cell lung cancer (SCLC) patients.

DESIGN

Previously untreated SCLC patients with no other malignancy, but in some cases with mixed histological subtype, who had symptomatic brain metastases verified by contrast enhanced CT-scan, were treated with a multidrug combination chemotherapy regimen and no cranial irradiation. Radiotherapy was optional at cranial relapse or progression at the discretion of the physician in charge. The intracranial effect was evaluated by 4-weekly CT-scan and neurological examination, according to a standardized scoring system.

END POINTS

Intracranial response, duration of response, neurological score, terminal CNS status, and survival.

RESULTS

21 patients were included, corresponding to 8.6% of consecutive SCLC patients at our institution. 8 patients died before follow-up leaving 13 evaluable for response. In the former group, all patients had WHO performance status of 3-4 compared to 6/13 in the latter group. Of the 13 evaluable patients, 1 had early progression in the CNS and 1 had no change. 11 had CT-scan verified response, with a median duration of 135 days. Most patients, including all complete responders, had improvement in their neurological score. 6 out of 11 responders died without active CNS disease. The crude median survival was 111 days, whereas the median survival (early deaths excluded) was 197 days.

CONCLUSION

Systemic combination chemotherapy was effective for palliation of initial brain involvement in the majority of patients in a small consecutive series. The role of consolidating cranial irradiation in responders should be assessed by a randomized trial.

Intratumoral pharmacokinetic analysis by 19F-magnetic resonance spectroscopy and cytostatic in vivo activity of gemcitabine (dFdC) in two small cell lung cancer xenografts

BACKGROUND

Gemcitabine, 2'2'difluoro-deoxycytidine (dFdC), has shown activity in several preclinical models, and presently the compound is being clinically evaluated in patients with lung cancer and other solid tumors.

DESIGN

The cytostatic in vivo activity of dFdC was tested in the two human small cell lung cancer (SCLC) tumor xenografts CPH SCCL 54A and 54B in nude mice. Non-invasive monitoring of the uptake and elimination of fluorine in the individual tumors was performed by in vivo 19F-magnetic resonance spectroscopy, using a 2.9 T magnet. Five dose levels in the range 5-80 mg/kg i.p. every third day, four times were applied.

RESULTS AND CONCLUSION

Significant activity of gemcitabine was demonstrated in both SCLC tumor lines. The tumor line 54A is the most sensitive to radiotherapy, doxorubicin, and nitrosoureas; but in this case the 54B tumors were more sensitive to gemcitabine therapy than 54A. This difference in sensitivity seems to be related to different delivery or uptake of the compound in the two tumor lines, since the 19F-MRS demonstrated a significantly higher antitumor accumulation of fluorine in 54B tumors compared with 54A (p < 0.05, Wilcoxons 2-sided test) following the same single dose of the drug.

Systemic chemotherapy of brain metastases from small-cell lung cancer: a review

PURPOSE

For decades the treatment of choice in small-cell lung cancer (SCLC) with brain metastases has been corticosteroids and radiotherapy (RT) because of a presumed lack of penetrance of cytostatic agents into parenchymatous brain metastases. In recent years, several reports have appeared on radiologic and clinical responses to systemic chemotherapy without additional RT in patients with metastatic SCLC in the brain. We reviewed the literature and focused on the methodologic aspects in comparison with RT data.

DESIGN

We reviewed 12 patient series that included 116 patients and were published between 1981 and 1990.

RESULTS

The overall brain response to chemotherapy without irradiation in patients with intracranial metastases at diagnosis was 76%, whereas the response rate of brain relapses was 43%.

CONCLUSIONS

We conclude that intracranial metastases from SCLC seem to respond to chemotherapy as readily as other metastatic locations of SCLC do. Thus first-line cranial irradiation probably should be applied routinely only in cases of delayed brain metastases. Whether consolidating cranial RT should be given after a few courses of initial chemotherapy in SCLC patients with brain metastases at diagnosis is unclear and warrants a randomized evaluation.

Different early effect of irradiation in brain and small cell lung cancer examined by in vivo 31P-magnetic resonance spectroscopy

Early effects of irradiation were evaluated by non-invasive in vivo 31P-magnetic resonance spectroscopy (31P-MRS) of two small cell lung cancer (SCLC) tumor lines CPH SCCL 54A and 54B, in nude mice. The tumors were originally derived from the same patient and have similar morphology and growth characteristics, but a different radiosensitivity. The 54A tumors are twice as radiosensitive as the 54B's. In the present study the tumors were treated with 2.5, 10, and 40 Gy. For comparison, nude mice were given cranial irradiation at the same three doses, and the effect was evaluated by in vivo 31P-MRS. No effect was observed in brain at any dose level. In contrast, 40 Gy induced a statistically significant reduction in ATP/Pi ratio during the 12-h post-irradiation period. This effect was more pronounced in 54A than in 54B. Some reduction was observed following 10 Gy, whereas 2.5 Gy induced no changes in ATP/Pi. The differential effect on tumors and brain might be relevant for monitoring irradiation effects by in vivo 31P-MRS in patients with brain metastases.

Biochemical and physiological changes induced by nicotinamide in a C3H mouse mammary carcinoma and CDF1 mice

We have continued our investigation into the mechanism by which nicotinamide can enhance radiation damage in tumors, using a C3H mouse mammary carcinoma grown in CDF1 mice. Biochemical analysis of tumor extracts showed that nicotinamide (1000 mg/kg; i.p.) increased the ATP/Pi and ATP/ADP + AMP ratios. This change in metabolic activity was consistent with nicotinamide increasing tumor oxygenation. Moreover, the greatest effect occurred 0.5-2.5 hr after drug injection, a time at which radiosensitization by nicotinamide in this tumor had previously been shown to be maximal. These changes were observed without any apparent modification in tumor blood perfusion, measured using the 86-RbCl uptake procedure, and occurred despite nicotinamide producing a 50% decrease in mean arterial blood pressure, estimated directly by a carotid cannulation technique.

Different energy metabolism in two human small cell lung cancer subpopulations examined by 31P magnetic resonance spectroscopy and biochemical analysis in vivo and in vitro

Two human small cell lung cancer tumor lines, maintained as solid tumor xenografts on nude mice and as in vitro cell cultures, were studied by in vivo 31P magnetic resonance spectroscopy and by biochemical analysis of extracts of solid tumors and cell cultures. The tumor lines CPH SCCL 54A and CPH SCCL 54B are subpopulations from the same tumor. In solid tumors (n = 125), the ATP/Pi ratio was greater in 54A than in 54B. This was due to a higher ATP level in 54A, whereas there was no difference in Pi, ADP, and AMP. A decrease in ATP/Pi during growth was caused by a decline in ATP, whereas Pi remained unchanged. Small amounts of phosphocreatine were found in the xenografts and in tumor extracts, but not in the cell extracts; correspondingly, there was a low creatine kinase activity in solid tumors and no activity in the cell cultures. Thus, the phosphocreatine content of the solid tumors originated from the stroma. A difference in ATP content between 54A and 54B was also found in cell cultures; hence, the metabolic difference is an intrinsic quality of the malignant cells and is not caused by the host system.

Second-line chemotherapy in small cell lung cancer

The literature on second-line chemotherapy in small cell lung cancer (SCLC) for the period 1979-1989 is reviewed. The reports consisted mainly of Phase II type studies and comprised a total of 987 patients with relatively few patients per study. The information was frequently incomplete with regard to duration of response on first-line chemotherapy, length of any drug-free interval and duration of response on second-line chemotherapy. The overall second-line response rate was 30%, but only 5% were complete responses (CR). The response rates obtained by the combination of cisplatinum (P) and VP-16 (E) or reinduction therapy were 45% and 64% (medians), respectively. These rates were superior to regimens consisting of supposedly non-cross-resistant agents. With P and E not given in combination, the response rates were less than 20%.

Early effects of radiotherapy in small cell lung cancer xenografts monitored by 31P magnetic resonance spectroscopy and biochemical analysis

31P magnetic resonance spectroscopy (31P MRS) and biochemical analysis of extracts were applied to study the metabolic response to X-irradiation of small cell lung cancer in nude mice. Two small cell lung cancer xenografts, CPH SCCL 54A and 54B, with different radiosensitivity, although derived from the same patient, were studied. A total of 126 individual tumors were examined. Following 5.0-Gy irradiation, a reversible increase in the ATP/Pi ratio, reaching twice the pretreatment level within 2 wk, was observed with 31P MRS, while 20 Gy induced a reversible decrease in the ATP/Pi ratio. The t1/2 of this decline was 2 to 3 h for 54A and about 6 h for the less radiosensitive 54B. The 31P MRS data were compared with biochemical analysis of tumors freeze-clamped and extracted at similar intervals after 20 Gy. It appeared that an acute reversible increase in Pi concentration was the major cause of the ATP/Pi decrease induced by 20 Gy. A linear correlation between ATP/Pi estimated by 31P MRS and by analytical biochemistry was found. The ATP/Pi ratio may be valuable for early assessment of radiosensitivity of small cell lung cancer tumors.

Pulmonary absorption of instilled and inhaled DTPA in smokers

Pulmonary absorption of DTPA (diamine-triethylene-penta-acetic acid) has been widely adopted as an index of pulmonary epithelial permeability. The aim of this study was to analyse: (1) if measurements of pulmonary absorption are influenced by the amount of fluid being administered to the lungs together with the DTPA; and (2) if all DTPA administered to the lungs is equally accessible for pulmonary absorption. To this end DTPA was instilled into a lung segment of six smokers in association with a bronchoscopy. In six other subjects (five smokers and one ex-smoker) the DTPA was inhaled as an aerosol. Pulmonary absorption of DTPA was calculated from the plasma DTPA content, as determined for 4-10 h after the administration of the DTPA. We found that the mean transit time for the absorption of instilled DTPA, t(L), across the pulmonary membranes was significantly (P less than 0.05) longer (median 1498 min, range 955-2636 min) than the t(L) of the absorption of the inhaled DTPA (median 131 min, range 44-512 min). Pulmonary clearance of the inhaled aerosolized DTPA tended to be faster when determined by external detection for 4 h, than when estimated from plasma samples, suggesting that not all pulmonary DTPA may be equally accessible for absorption from the pulmonary lining fluids. We conclude that pulmonary absorption of DTPA is influenced by the volume of fluid being administered to the lungs in association with the measurements. Not all pulmonary DTPA, however, is equally accessible for absorption, rendering external detection of pulmonary clearance of DTPA sensitive to a variety of factors other than pulmonary absorption.

Brain metastases from small cell lung cancer treated with combination chemotherapy

Ten patients with metastatic small cell lung cancer (SCLC) in the brain, shown by CT scan at time of diagnosis, were treated with systemic combination chemotherapy. Repeated CT scans were performed every 4 weeks. Seven patients were evaluable, since three patients died during the first 2-3 weeks. Significant responses on CT scans as well as neurologic improvement were demonstrated in all evaluable patients. Four of seven patients obtained a complete response in the brain, while three had partial remissions. The impact of this observation on the overall treatment strategies in SCLC has further to be defined.

Hypouricemia and urate excretion in small cell lung carcinoma patients with syndrome of inappropriate antidiuresis

Urate concentrations in serum and renal urate clearance were prospectively evaluated in patients with small cell lung cancer (SCLC). Serum urate and renal urate clearance were measured before and during cytostatic treatment until disease progression (PD) in 12 patients with the syndrome of inappropriate antidiuresis (SIAD) and in 8 patients without. Hypouricemia occurred in 4 SIAD patients before treatment and also when tumor regression was obtained. Two normouricemic SIAD patients developed hypouricemia when PD occurred. No patient without SIAD experienced hypouricemia. Serum urate in patients with SIAD was lower than in those without SIAD before cytostatic treatment but not 3 months after the treatment. Hypouricemic patients had higher urate clearance than normouricemic and it remained higher even after tumor regression. Serum urate was invalid as marker of tumor regression or relapse. SIAD patients have higher glomerular filtration rates than patients without SIAD, which may influence the renal excretion of cytostatic drugs.