Interactions between the local tumor and its metastases

Intensive chemotherapy in children with stage IV neuroblastoma

A retrospective analysis of effectiveness of sequential chemotherapy with cyclophosphamide, doxorubicin, cisplatin and etoposide in children with stage IV neuroblastoma was undertaken. Study group included 17 children of mores than one year old with median age of 3 years (range 18 months to 7 years). Fourteen were males and three females. Sites of primary tumor were abdomen in 12 patients, pelvis in 3, paravertebral in 1 and unknown in 1. Metastatic sites included bone marrow (88%), bone (82%), orbit (29.4%) and lymph node (11.7%). One patient had brain parenchymal disease and another had cerebrospinal fluid positivity for malignant cells. Fifteen of the 17 patients had major response with chemotherapy (complete response in two and partial response in 13). Ten of the 15 patients completed four courses of chemotherapy and five patients progressed while on chemotherapy and died. Only two of the ten patients, who had four courses chemotherapy are alive after 2 years. Hence the 2-year survival in this series is 11.7%. There was no toxic death in this study.

The role of surgery in the management of stage IV neuroblastoma: a single institution study

The role of surgery in the management of Stage IV neuroblastoma is still far from clear. Seventy-nine patients with this diagnosis presented to the Children's Hospital of Philadelphia during the 10-year period, 1977 to 1986. Four-year survival was 23%. A major resection of the primary tumor was undertaken in 54 patients. The timing of the procedure (at presentation or delayed) had no effect on survival. The patients were divided into three groups based on the extent of surgical resection: Group 1, no surgery or biopsy only (25); Group 2, complete gross resection (34); Group 3, incomplete resection with residual gross disease (20). Four-year survival was 16, 15, and 45%, respectively. The patients were then classified as favorable or unfavorable, on the basis of biological prognostic factors at presentation. When this analysis was combined with the extent of surgery it was discovered that Group 3 contained a higher proportion of favorable patients, accounting for the better survival. Within each group survival correlated with the expected prognosis. The outcome for a patient with Stage IV neuroblastoma depends on the biological characteristics of the tumor, and there is currently no evidence that these can be favorably altered by the timing or extent of surgical resection. Defining the appropriate role of surgery in the management of these patients will require a prospective randomized study which takes into account the inherent biological variability of the disease.

Growth patterns of pulmonary metastases and primary tumours from five murine fibrosarcoma cell clones

The growth patterns, including the size, shape and regional preferences, of lung metastases from five murine fibrosarcoma cell clones were studied. Spontaneous metastases developed from tumours formed by subcutaneous inoculation of the cell clones. Lung colonies (experimental metastases) were established by i.v. injection of cells. The numbers of both spontaneously and experimentally formed subpleural lung metastases were counted through a stereomicroscope. The fraction of colonies that was located subpleurally was determined in histological sections of lungs. The growth kinetics of clonally derived primary tumours, and the number of spontaneous and experimental lung metastases, differed greatly between certain cell clones. The number of spontaneous lung metastases was correlated with the maximum size of primary tumours. No close correlation was observed between the size of the primary tumours and the size of experimental metastases. There were differences between the cell clones in the shape and regional preferences of their lung deposits. The subpleural colonies were generally larger than the intrapulmonary ones. Thus, both the regional distribution and the growth pattern of lung deposits differed between the clones.

Growth of metastases of the mouse adenocarcinoma EO 771: an allometric relationship between growth of the primary tumors and their metastases

Growth and cell kinetic parameters have been studied of paraaortal lumbar lymph node metastases of the mouse adenocarcinoma EO 771 growing intramuscularly in the thigh. An allometric relationship was found between the growth of the metastasis and that of the primary tumor, i.e. a linear relationship exists between the logarithm of the size of the metastasis and that of the primary tumor which permits the estimation of the growth rate of the metastasis based on the growth curve of the primary tumor. However, growth of metastases differs quantitatively from that of the primary tumor: the specific growth rate (growth rate per unit size) of the metastasis (1) is greater than that of the simultaneously growing primary tumor but (2) is smaller than that of the primary tumor of the same size as the metastasis. The allometric growth relationship further suggests that metastases originate later than is generally predicted presuming exponential growth of metastasis.

Sensitivity of locally recurrent rat mammary tumour cell lines to syngeneic polymorphonuclear cell, macrophage and natural killer cell cytolysis

Using a recently developed model for studying the biology of locally recurrent (LR) mammary tumours in the 13762NF rat mammary adenocarcinoma system, we examined the sensitivity to polymorphonuclear cell, macrophage and natural killer cell cytolysis. The parental MTF7(T20) cell line; the 'primary' tumours which arose following subcutaneous inoculation into the mammary fat pad, sc1 and sc3; and the local recurrences (following surgical excision) LR1 and LR1a from sc1, and LR3 from sc3 were all cells generally resistant to specific PMN cytolysis. LPS-activated macrophages caused 25.1%, 38.7% and 58.8% specific cytolysis in MTF7, sc1 and LR1 cells, respectively at E:T of 20:1 and 72 h co-incubation. LR1a, sc3 and LR3 lysis ranged from 0-4.4% under the same conditions. Non-activated macrophages did not lyse any of the cell lines. Locally recurrent and 'primary' tumour cell lines were also not lysed by naive NK cells (range 0.5-4.0% cytolysis). NK cells activated with bropirimine, a potent immunomodulator currently being studied in clinical trials, and/or interleukin-2 were mildly more effective at killing LR cells. Our results show that locally recurrent tumours exhibit heterogeneous sensitivities and are different from 'primary' tumour cells in sensitivities to immune cell killing, but they are not necessarily more or less sensitive. Results with bropirimine-activated or IL-2-activated NK cells emphasize that nonspecific activation is insufficient to eliminate all tumour subpopulations.

Abrogation of metastatic properties of tumour cells by de novo expression of H-2K antigens following H-2 gene transfection

H-2 gene transfection was used to restore expression of H-2K antigens in metastatic and non-metastatic subclones of a murine fibrosarcoma that lack their major histocompatibility complex-encoded H-2K antigens. De novo expression of H-2K reduced tumorigenicity and abolished the formation of metastasis in syngeneic mice. Expression of H-2K may lead to effective recognition of the disseminating tumour cells by the host immune system.

Antigen-specific therapy of experimental metastases

In a methylcholanthrene-induced tumor (MCA-F) model in C3H/HeJ mice, curative resection of a progressive tumor promotes artificial lung metastases following intravenous injection of a highly metastatic cell variant designated clone 9-4. The number of metastatic lung colonies depends upon the status of host immunity at the tumor resection: mice resected 7 or 14 days, but not 28 days after tumor inoculation display significantly retarded postoperative, experimentally induced lung metastases. The number of lung colonies in mice that had tumors resected at 14 days was three times greater than in mice that had 28-day neoplasms resected. Neither therapy with weekly injection of 50 micrograms tumor-specific transplantation antigen, which had been extracted using a single phase of 2.5% 1-butanol (CBE), nor 20 mg/kg cyclophosphamide (CY) alone prevented lung colonization. Assessment of helper-suppressor ratios in the spleen from mice after tumor surgery showed that CBE administration decreased the ratio in mice after resection of 14-day tumors, but not after resection of 28-day tumors. Combined therapy with specific tumor antigen and an antisuppressor cell agent reduced metastases, regardless of the tumor size.

Investigation of a new murine model of regional lymph node metastasis: characteristics of the model and applications

The RC tumor, originally a renal adenocarcinoma very sensitive to different classes of chemotherapeutic agents, maintained in CDF 1 mice, was examined for its ability to metastasize. When inoculated into the foot (with 10(7) tumor cells), bulky metastases developed in the popliteal and para-aortic lymph nodes, in a constant and reproducible pattern, producing a massive microscopic invasion of the liver, the lungs and the spleen. The antigenicity tests demonstrated a low immunogenicity of the tumor. Chemotherapy assays showed that adriamycin and vincristine were effective against metastatic dissemination when administered early after tumor cell inoculation and principally when combined with excision of the tumor-bearing leg. The RC model appears to be suitable for the study of lymph node metastasis and could be used in chemotherapy trials of new drugs potentially effective against metastases of the lymphatic system.

Surgery for pulmonary metastasis: a 20-year experience

During a recent 20-year period, 556 patients underwent operation for pulmonary metastasis at the University of Texas M.D. Anderson Hospital and Tumor Institute at Houston. The surgical mortality was 1.5% for 772 resections. A selection of 443 patients was made to evaluate the contribution of operative intervention as a primary treatment, with selective adjunctive therapy when applicable. The success of a surgical approach is dependent primarily on adherence to selection criteria; it is important that only patients in whom all known disease can be completely removed with the planned resection and who have full control of the primary site are treated. The overall survival for the group was 35%. For patients with carcinoma, survival ranged from 24% for those with primary uterine cervix tumors to approximately 54% for urinary tract, male genital tract, and corpus of uterus primary tumors. In the group with sarcoma, patients with skeletal tumors had a 46.4% survival rate (50.7% for those with osteogenic sarcoma), and 33% of the patients with soft tissue tumors had long-term survival. The outcome for patients with melanoma was poor; only 12.1% survived 5 years. If the original criteria apply, multiple and bilateral lesions can be successfully managed. Patients undergoing planned adjuvant treatment had a superior outcome compared with those not so treated. However, a significant survival advantage was shown only for patients with sarcoma. The failure to control all disease in patients in whom pulmonary metastasis is controlled surgically can only be improved on through the use of systemically active adjuvant treatment.

Cell surface molecules and tumor metastasis. Regulation of metastatic phenotypic diversity

Metastatic tumor cells are characterized by quantitative alterations in cell surface and other properties that confer to these cells their abilities to invade, disseminate, implant, survive and grow at secondary sites. Metastasis is also determined by a variety of host factors that prevent, allow or even stimulate metastatic processes. The emergence of diversified cell subpopulations in malignant tumors insures that some cells will ultimately become highly metastatic, resulting in tumor progression towards characteristics which are the most favorable for survival and growth. Unknown mechanisms appear to stimulate and then to control phenotypic diversification of tumor cell subpopulations. These mechanisms may be altered by genetic (mutational) and/or epigenetic (non-mutational) modifications that individually influence cells within a malignant neoplasm.

Influence of implantation site on formation of metastases

It has been suggested that local factors at the site of growth of a primary tumor might influence the outcome of the metastatic process. Compilation of the data from the literature revealed that growth of tumor cells in the selective medium of the intraperitoneal cavity, of the lymph node and/or of the spleen leads to progression towards a population of cells with a higher metastatic capacity. In search for an experimental model with transplantable rodent tumors that could be used to study the influence of the anatomic site of an implant on the formation of spontaneous metastases, we have considered heterogeneity of microenvironmental conditions in the subcutaneous milieu. For the MO4 mouse fibrosarcoma, a primary tumor growing subcutaneously in the tail was highly metastatic to lymph nodes and lungs while it failed to produce metastases when growing in the pinna. Implantation of a spheroidal aggregate of MO4 tumor cells, alternatively in the tail and in the pinna of syngeneic C3H/He mice, might be an appropriate model, which is discussed in this review.