Simulation code for the interaction of 14 MeV neutrons on cells.

The structure of the survival curve of melanoma cells irradiated by 14 MeV neutrons displays unusual features at very low dose rate where a marked increase in cell killings at 0.05 Gy is followed by a plateau for survival from 0.1 to 0.32 Gy. In parallel a simulation code was constructed for the interaction of 14 MeV neutrons with cellular cultures. The code describes the interaction of the neutrons with the atomic nuclei of the cellular medium and of the external medium (flask culture and culture medium), and is used to compute the deposited energy into the cell volume. It was found that the large energy transfer events associated with heavy charged recoils can occur and that a large part of the energy deposition events are due to recoil protons emitted from the external medium. It is suggested that such events could partially explain the experimental results.

Effects of low-dose neutrons applied at reduced dose rate on human melanoma cells.

Human melanoma cells that are resistant to gamma rays were irradiated with 14 MeV neutrons given at low doses ranging from 5 cGy to 1.12 Gy at a very low dose rate of 0.8 mGy min(-1) or a moderate dose rate of 40 mGy min(-1). The biological effects of neutrons were studied by two different methods: a cell survival assay after a 14-day incubation and an analysis of chromosomal aberrations in metaphases collected 20 h after irradiation. Unusual features of the survival curve at very low dose rate were a marked increase in cell killing at 5 cGy followed by a plateau for survival from 10 to 32.5 cGy. The levels of induced chromosomal aberrations showed a similar increase for both dose rates at 7.5 cGy and the existence of a plateau at the very low dose rate from 15 to 30 cGy. The existence of a plateau suggests that a repair process after low-dose neutrons might be induced after a threshold dose of 5-7.5 cGy which compensates for induced damage from doses as high as 32.5 cGy. These findings may be of interest for understanding the relative biological effectiveness of neutrons and the effects of environmental low-dose irradiation.

[Cell cycle regulation after exposure to ionizing radiation]. / Régulation du cycle cellulaire des cellules exposées aux radiations ionisantes.

When cells are exposed to ionizing radiation, they initiate a complex response that includes the arrest of cell cycle progression in G1 and G2, apoptosis and DNA repair. DNA is an important subcellular target of ionizing radiation, but oxydative damage to plasma membrane lipids initiates signal transduction pathways that activate apoptosis and that may play a role in cell cycle regulation. How is DNA damage converted into intracellular signals for cell cycle arrest? The ataxia telangectasia mutant (ATM) protein and/or the DNA-dependent protein kinase (DNA-PK), that are both activated by DNA damage, may initiate cell cycle arrest by activating the p53 tumor suppressor protein. The p53 protein acts as a transcription factor and regulates expression of several components implicated in pathways that regulate cell cycle progression. The best known, p21WAF1/CIP1 protein, is an inhibitor of cyclin-dependent kinases (CDK), a family of protein kinases known as key regulators of cell cycle progression. p21WAF1/CIP1 was shown to be able to inhibit several CDK, but is most effective toward G1/S cyclins. Other CDK inhibitors, p27KIP1 and p15INK4b are activated by irradiation and contribute to the G1 arrest. Moreover, radiation-induced G2 arrest was shown to require inhibitory phosphorylation of the kinase cdc2 via an ATM-dependent pathway. Mutations in cell cycle regulatory genes are common in human cancer and cell cycle regulatory deficiency can lead to increase resistance to ionizing radiation in cancer cells. The major function of p53-dependent G1 arrest may be elimination of cells containing DNA damage whereas G2 arrest following radiation has been shown to be important in protecting cells from death. Cell cycle checkpoints offer a new set of potential targets for chemotherapeutic compounds, especially the G2 checkpoint. Thus, abrogation of the G2 checkpoint with methylxanthines such as caffeine or protein kinase inhibitors such as staurosporine and UCN-01 (7-hydroxystaurosporine) was found to sensitize cells to ionizing radiation. These data did not lead to clinical applications, but confirm targeting of the G2 checkpoint may be an important strategy for cancer therapy.

[Gene transfer and radiotherapy]. / Transfert génique et radiothérapie.

Recent studies have shown that experimental tumors could be treated more efficiently with ionizing radiation if genetic material was transfered into tumor cells. Several approaches have been reported, and among them, the first one consisted of increasing the apoptotic response to radiation by modulating genes involved in the regulation of the apoptotic pathway. Indeed the modulation of p53 and bcl-2 gene expression has recently been used successfully in several experimental models to increase the apoptotic death after radiation. A second approach consisted of taking advantage of the conditional expression of some genes after exposure to ionizing radiation. Indeed, some genes exhibit a radio-inducible promoter which can be combined to a gene, able to enhance or decrease the biological effect of radiation. The irradiation of such a transgene under the control of a radio-inducible promoter can lead to a second biological effect, concomitant to the irradiation, as reported for the TNF alpha under the control of the EGR (early growth response) promoter. A third approach consisted of enhancing the effect of radiation induced tumor cell death by the expression of a suicide gene in these cells, as suggested recently for the HSV-tk (herpes virus thymidine kinase gene). These preliminary results obtained in experimental models appear to be very promising and might improve the efficacy and specificity of radiation therapy in a not too distant future.

High-dose therapy and autologous bone marrow transplantation in first complete or partial remission for poor prognosis Hodgkin's disease.

We report the experience of three French centres which evaluated high-dose therapy (HDT) as consolidation therapy for poor prognosis Hodgkin's disease (HD). From March 1986 to April 1990, 23 consecutive patients with poor prognosis stage IV HD underwent HDT followed by autologous bone marrow transplantation (ABMT) after achieving either complete remission (CR1) or good partial response (GPR1) (reduction mass> 75%). The median age was 31 years (range 18 to 55 years), 14 were male. All patients except one initially had at least 2 poor prognosis factors such as: systemic symptoms (n = 19), bulky tumor (n = 16), more than one extranodal site (n = 9), bone marrow involvement (n = 5), lymphocyte count < or = 1.10(9)/1 (n = 8) and biological stage B (n = 21). All patients had previously been treated with alternating MOPP/ABVD. Ten patients were in GPR1 and 13 in CR1 before transplant. The conditioning regimens were: CBV (n = 17), BEAM (n = 5), BEAC (n = 1) followed by bone marrow rescue. Radiotherapy was introduced just before the conditioning regimen for 6 patients or after ABMT for 5 patients. Nine of 10 patients in GPR1 achieved CR after ABMT but one died early of treatment-related toxicity. Five of 22 patients who were in CR posttransplant, relapsed (3, 4, 4, 18, 36 months). Seventeen patients remain alive in continuous CR with a median follow-up of 60 months (range: 30-100 months). The overall survival (OS) and disease-free survival (DFS) projected at 5 years are 92% and 77% respectively. Consolidation by HDT and ABMT proved to be well tolerated. An international trial is currently underway to attempt to demonstrate a clear benefit on survival for this subset of poor prognosis HD patients.

The hematopoietic stem cell transplantation in Hodgkin's disease: questions and controversies.

Most patients with Hodgkin's disease (HD) are cured with chemotherapy and/or radiotherapy. However, half of those with advanced stage disease (IIIB, IV) do not respond adequately to treatment or relapse. Salvage therapy used in such cases gives from 10% to 50% complete remission but only 10% long term survival. The results of bone marrow transplantation reported in acute leukemia and non-Hodgkin's lymphoma encouraged some authors to develop this new therapeutic strategy in Hodgkin's disease. In the early 1980's promising results were achieved when refractory and relapsed patients were selected to receive myeloablative therapy followed by bone marrow transplantation. Today, high dose chemotherapy with hematopoietic stem cell transplantation (HSCT) is used more and more often in poor prognosis Hodgkin's disease. After a review of the literature concerning the results of transplantation in Hodgkin's disease, we develop the numerous problems associated with this procedure which remain to be solved such as: the optimal indication, the timing of HSCT, the type of graft, the conditioning regimen, the place of radiotherapy and the optimal use of hematopoietic growth factors. We conclude with future prospects.

[Prognostic value of beta-2-microglobulin in Hodgkin disease in young adults]. / Valeur pronostique de la bêta-2-microglobuline dans la maladie de Hodgkin de l'adulte jeune.

From 1977 to 1989, we measured serum beta-2-microglobulin (beta 2-MG) levels from 64 unselected and untreated patients, between 18 to 50-year-old, affected by Hodgkin's disease. Serum beta 2-MG level was measured by radioimmunoassay (Phadebas beta 2 microtest). Then, all patients received a chemotherapy such as MOPP or alternating MOPP/ABVD followed or not by radiotherapy. Elevated serum beta 2-MG level (> 2.4 mg/l) is associated with advanced stage disease (stage III-IV), presence of systemic symptoms and bulky tumor. Nevertheless, a multivariate analysis shows that the serum beta 2-MG level is the most significant prognostic indicator for disease free survival. The prognostic value of serum beta 2-MG is demonstrated for myeloma and non Hodgkin's lymphoma. A few authors have evaluated the prognostic impact of serum beta 2-MG in Hodgkin's disease. This study requires confirmation by multicentric and prospective trial.

Clinical relevance of immunohistochemical detection of multidrug resistance P-glycoprotein in breast carcinoma.

In 20 women with breast carcinoma, 17 of whom had locally advanced cancer and 3 of whom had confirmed metastases, the expression of P-glycoprotein was evaluated before the start of a chemotherapy regimen that included multidrug resistance-related drugs. With the use of the C494 monoclonal antibody in an avidin-biotin-immunoperoxidase technique, P-glycoprotein was detected in 17 of 20 tumor samples. Results were expressed in a semiquantitative manner, taking into account the number of positive tumor cells (N index) and the specific staining intensity (I index). The 17 patients with nonmetastatic cancer were followed from the first cycle of chemotherapy to cancer recurrence; subsequent to six cycles of chemotherapy, all of these patients except one were rendered clinically disease-free through surgery and/or radiation. The end point was defined as either local/regional recurrence or metastasis. Strong P-glycoprotein-positive staining in a majority of tumor cells (the N+/I+ phenotype) was significantly correlated with no initial response to chemotherapy (P less than .02) and with a shorter progression-free survival (P less than .02). Thus, the pretreatment evaluation of P-glycoprotein expression may be of prognostic value in patients with locally advanced breast cancer.

[Treatment of malignant intracranial germ-cell tumors in children. 7 cases]. / Traitement des tumeurs germinales malignes intracrâniennes de l'enfant. Sept cas.

Seven children, aged from 9 to 16 years, with intracranial germ cell tumour received post-operative chemotherapy prior to radiotherapy. Treatment consisted of several courses of vinblastine, bleomycin and cisplatin alternating or not with courses of cyclophosphamide and actinomycin D. In the 6 children whose tumours secreted alphafoetoprotein or chorionic gonadotrophin, chemotherapy brought these markers down to normal. Tumoral regression at radiology exceeded 75 per cent in 6 patients. These results demonstrate the effectiveness of chemotherapy against intracranial germ cell tumours such as pure germinomas or secreting tumours. They encourage the systematic use of pre-irradiation chemotherapy in order to reduce the radiation doses delivered and to improve the prognosis.

Initial chemotherapy and low-dose radiation in limited fields in childhood Hodgkin's disease: results of a joint cooperative study by the French Society of Pediatric Oncology (SFOP) and Hôpital Saint-Louis, Paris.

To minimize the drawbacks of treatment we had shown in a previous study that it was possible after chemotherapy to limit the radiation fields to the involved areas only. Pursuing our policy of deescalation, we started in January 1982 a study in 29 French pediatric and hematologic centers, with two aims: (1) To compare the efficacy of 4 cycles of two different chemotherapeutic regimens (4 ABVD vs 2 MOPP + ABVD) in early stages (CSIA and II A) while other stages would receive 6 cycles of the same regimen (3 MOPP + 3 ABVD); (2) To evaluate the efficacy of irradiation given at a low dose (20 Gy) in the patients who had a minimum 70% reduction of the size of their nodes (good responders). From January 1982 to March 1987, 174 patients were entered in this study, of whom 157 completed their treatment program at the time of analysis. On completion of chemotherapy, 94% were considered as good responders and were irradiated to 20 Gy. Only 6 patients received a mediastinal boost (up to 40 Gy). Of the 6% (10/157) poor responders a complete remission was obtained in 6 after 40 Gy. Among the good responders, 5 patients relapsed, with only 3 within an area irradiated to 20 Gy. So that 4 nodal relapses occurred among 364 involved lymph areas. The actuarial survival at 42 months (median 30 months) is 95% (IA + IIA = 100%, IB + IIB + III = 94% and IV = 80%) and the disease-free survival 88% (respectively 94, 93 and 54). Until now there is no statistically significant difference between the 2 randomized arms. This study shows that it is possible to achieve a durable remission in most children treated with a less toxic protocol eliminating or reducing Nitrogen Mustard and reducing the dose of irradiation. Less late complications and sequelae are expected with a longer follow-up.

Sequential combination of 5-fluorouracil, cis-platinum and irradiation. 1. Advanced head and neck cancers.

Based on the synergistic action of 5-fluorouracil (5-FUra), cis-dichlorodiamminoplatinum(II) (cis-DDP) and gamma-rays, which was suggested in experiments on murine tumours, a sequential treatment combining irradiation and chemotherapy for human solid tumours known to be resistant to conventional treatments has been developed. A pilot study was carried out on 30 patients with recurring head and neck cancers previously treated by radiotherapy and surgery. The good tolerance and the initial results justified applying this protocol to previously untreated cases. The second study involved 40 patients with stage III and IV tumours. After 3 cycles of combined radio- and chemotherapy followed by a conventional radiotherapy, 78% were good responders (51% in complete remission). Oropharynx and oral cavity, without base of tongue, have a 51% actuarial survival at 3 years when they achieved an early complete remission.

Chemotherapy with low doses of radiation followed by definitive radiotherapy for advanced unresectable carcinoma of the head and neck.

Thirty-six patients with advanced unresectable carcinoma of the head and neck were treated with a combination of three courses of chemotherapy and low doses of radiation, followed after 3 weeks by definitive irradiation. Each course was repeated every 3 weeks with the following sequence. Cisplatin (20 mg/m2) was given in a 20-minute infusion, followed by a 2-hour infusion of 5-fluorouracil (400mg/m2), on days 1,2,5, and 6. Low doses of radiation were given on days 3 and 4, followed by a 2-hour infusion of 5-fluorouracil (400 mg/m2) with a dose of 3 Gy on the target volume. For definitive irradiation, a total dose of 60 Gy was delivered in 30 fractions within 6 weeks. The complete response rate reached 30%, and the partial response rate was 30%. With a median follow-up of 11 months, median overall survival was 10 months; median survival was 21 months for patients with complete response, 9 months for patients with partial response, and 6 months for those with no response (P=.02).

[Medical treatment of urothelial tumors of the bladder]. / Les traitements médicaux des tumeurs urothéliales de la vessie.

Intravesical chemotherapy is widely used in the management of superficial urinary bladder tumors. A complete response rate of 30 to 50% is observed in unresected tumors. Prophylactic instillations of the drugs after transurethral resection of the tumors seem able to delay recurrences. BCG can also be as effective, particularly in carcinoma in situ. Confirmation of efficacy of retinoids needs further studies. Invasive or metastatic bladder carcinoma can be responsive to systemic chemotherapy in about 40% of the cases for a period of 6 to 12 months. The value of adjuvant chemotherapy remains to be proved. Enhancement of radiation therapeutic effects by CisPlatinum in an interesting field of clinical research.

[Ureteral dosimetry during gynecological curietherapy. Possible effects on the occurrence of postoperative ureteral complications]. / La dosimétrie urétérale en curiethérapie gynécologique. Incidence possible sur la survenue des complications urétérales postopératoires.

The dosage of radiations delivered during gynaecological brachytherapy is usually calculated for the bladder and the rectum. A new technical approach is described in order to known the dose of radiation received by the terminal portion of the ureter. During placement of the Fletcher suit one of the ureters is catheterized by a special stent which appears on the X-rays control used for dosimetry. Data of 16 pre-operative brachytherapies for carcinoma of the cervix were studied. In half of the cases, the dose debit was higher on the ureter than on the bladder and the rectum. In 7 cases, the dose delivered was also higher on the ureter rather than on the bladder and the rectum. And in 3 cases this dose was higher than 50 grays. It is concluded that the ureter is frequently the most irradiated organ in the pelvis during brachytherapy for carcinoma of the cervix. This may be a physiopathologic explanation for some ureterovaginal fistulas occurring after radical hysterectomy.

A monoclonal antibody against LAV gag precursor: use for viral protein analysis and antigenic expression in infected cells.

A murine monoclonal antibody (MAb), named C.V.K., was produced after immunization with highly purified and sonicated lymphadenopathy-associated virus (LAV). No monoclonal antibody was observed with intact virus used as immunogen. C.V.K. MAb recognizes an epitope present on the precursor gag protein of 55 kilodaltons. Western blot analysis and pulse-chase experiments support the interpretation that after p55 cleavage into p25, p18, and p13, only p18 expresses this epitope. C.V.K. MAb selectively stained only LAV-infected lymphocytes. This intracytoplasmic staining appears 3 days after the infection and is correlated with reverse transcriptase activity. Neither membrane immunofluorescence of infected lymphocytes nor neutralizing activity was observed with C.V.K. MAb. These facts suggest that p55 and p18 are not expressed at the cell membrane or on the viral envelope. C.V.K. MAb should prove useful not only in the purification of core proteins but also for detecting infected cells producing the virus in suspension or on histologic sections.

[Pre and postoperative chemotherapy of osteosarcoma with an adriamycin-cisplatin combination. Risks of a neoadjuvant chemotherapy which is not sufficiently effective]. / Chimiothérapie de l'ostéosarcome par l'association adriamycine-cisplatinum pré et postopératoire. Risques de la chimiothérapie néoadjuvante lorsqu'elle n'est pas suffisamment efficace.

The authors evaluated a new protocol of neoadjuvant chemotherapy for osteosarcoma, easier to manage and different from T10. The good results obtained with the postoperative ADR-CDDP association led us to undertake a pilot study between 1982 and 1984, using ADR-CDDP as preoperative chemotherapy. The records of sixteen patients were available for follow-up. The average age of the patients was 19.9 years. Patients received two or three preoperative courses, and a total of six identical courses. Tolerance was good. Pain usually disappeared but this was often misleading because associated with radiological and/or clinical tumor progression, low histological necrosis or poor outcome. The continuous disease-free survival actuarial rate was less than 57 and 40% at 18 months and two years respectively. The actuarial survival rate was 87% at one year and 65% at two years respectively. Disappointing results of this preoperative protocol, compared to results with the SO4 78 or T10 protocols for example, led to publish these data early in order to underline their potential dangers. As a result, we stopped our study. The charter of pilot studies justifies this publication. As well, these data point out the necessity of very close follow-up of neoadjuvant chemotherapy by sophisticated medical imaging. Neoadjuvant chemotherapy, if ineffective, must be stopped early, and should lead to surgery, followed by adequate postoperative chemotherapy.