Alternating non-cross-resistant combination chemotherapy for small cell anaplastic carcinoma of the lung

Therapeutic resistance in lung cancer

Despite considerable progress over the last 25 years in the systemic therapy of lung cancer, intrinsic and acquired resistance to chemotherapeutic agents and radiation remains a vexing problem. The number of mechanisms of therapeutic resistance in lung cancer has expanded considerably over the past three decades, and the crucial role of stress resistance pathways is increasingly recognised as a cause of intrinsic and acquired chemo- and radiotherapy resistance. This paper reviews recent evidence for stress defence proteins, particularly RALBP1/RLIP76, in mediating intrinsic and acquired chemotherapy and radiation resistance in human lung cancer.

Optimal control of tumor size used to maximize survival time when cells are resistant to chemotherapy

The high failure rates encountered in the chemotherapy of some cancers suggest that drug resistance is a common phenomenon. In the current study, the tumor burden during therapy is used to slow the growth of the drug-resistant cells, thereby maximizing the survival time of the host. Three types of tumor growth model are investigated--Gompertz, logistic, and exponential. For each model, feedback controls are constructed that specify the optimal tumor mass as a function of the size of the resistant subpopulation. For exponential and logistic tumor growth, the tumor burden during therapy is shown to have little impact upon survival time. When the tumor is in Gompertz growth, therapies maintaining a large tumor burden double and sometimes triple the survival time under aggressive therapies. Aggressive therapies aim for a rapid reduction in the sensitive cell subpopulation. These conclusions are not dependent upon the values of the model constants that determine the mass of resistant cells. Since treatments maintaining a high tumor burden are optimal for Gompertz tumor growth and close to optimal for exponential and logistic tumor growth, it may no longer be necessary to know the growth characteristics of a tumor to schedule anticancer drugs.

Low-intensity combination chemotherapy maximizes host survival time for tumors containing drug-resistant cells

Recent clinical trials have shown that for some cancers, high-intensity alternating chemotherapy does not significantly improve either survival times or response rates compared with nonalternating therapy. The current study uses optimal control to determine the best way to treat a tumor that contains drug-resistant cells that cannot be destroyed. The delivery of two non-cross-resistant chemotherapeutic agents is limited by bounds on the drug concentration and the dose intensity. This ensures that the drug toxicity stays within a tolerable range. The aim of the therapy is to maximize the host survival time, defined as the time over which the tumor burden can be kept below a fixed bound. The model is posed as a free terminal time, optimal parameter selection problem in which the constraints are continuously parametrized by time and the number of courses of therapy is free to vary. New theory is developed so that the optimal parameter selection problem can be solved as a sequence of fixed terminal time problems using existing optimal control software. Numerical simulations of Gompertz tumor growth showed that a treatment maintaining a high tumor burden doubled and sometimes tripled with survival time under aggressive therapy. When these simulations were repeated using exponential and logistic tumor growth models, the tumor burden during treatment had little influence upon survival time. In all simulations, survival time was not extended by delivering the anticancer drugs concurrently instead of staggering the treatment arms.

[Sequential induction chemotherapy and radiation treatment of inoperable small cell bronchial cancer. Results of a prospective randomized study]

To study the potential benefit of sequential chemotherapy in inoperable small cell lung cancer (SCLC), from 1982 to 1986 ninety-one patients with histologically proven and previously untreated SCLC (median age: 53 years; median Karnofsky status: 80%) were randomly assigned to an initial therapy with adriamycin (since 1984 epirubicin), cyclophosphamide, vincristine (ACO resp. EPICO) or etoposide/cisplatin (VP16/DDP). Treatment courses were repeated every 3 weeks for a total of less than or equal to 6 courses with a crossover after a maximum of 3 cycles of either regimen. Limited disease (LD) patients with bronchoscopical, computertomographical and (re-) mediastinoscopical complete remission (CR) randomly received either a thoracic irradiation with 40 Gy or observation only. Overall, 60 out of 85 evaluable patients achieved an objective remission. A CR was observed in 24/51 patients (47%) with limited disease, and in 8/34 patients (24%) with extensive disease. Both, ACO (EPICO) and VP16/DDP were equally effective as initial and second-line therapy. Moreover, after failure to the initial therapy an objective remission could be achieved in 13% of the patients following the alternative second line combination. In 28% of LD patients with an otherwise complete remission residual tumor was detected by (re-) mediastinoscopy. Median survival times were 14 (CR: 16) months in LD patients and 10 (CR: 15) months in ED patients. At present, median survival is significantly improved in irradiated versus non-irradiated LD patients (25 vs. 13 months, p less than 0.04). The remission rates and median survival times observed in this study are comparable to those of a historical control group treated with ACO plus radiotherapy alone.

The prognostic value of response to the first cycle of chemotherapy in small cell lung cancer. Results of a multicenter German trial

The prognostic significance of evaluation of response according to chest X-ray after only one cycle of treatment was investigated in patients with small cell lung cancer (SCLC). Three hundred and six patients entered a multicenter randomized German trial testing alternating vs. sequential chemotherapy. Decrease of tumor size after the first cycle was seen to be 78% in the alternating group and 70% in the sequential group. Stable disease occurred in 25% of the sequentially treated and 19% of the alternatingly treated patients. No substantial differences in pretreatment characteristics were noticed between patients with stable disease in sequential and alternating treatment. In sequential therapy, median survival was 323 days for patients with decrease of tumor size after the first cycle and 219 days for patients with no change. Only five out of 21 patients with no change after one cycle responded to continuous administration of this regimen including one complete remission. In alternating therapy, median survival was 347 days for patients with decrease in tumor size after the first cycle and 378 days for patients with no change indicating no difference in prognosis. Twelve out of 18 patients with no change responded to continuous administration of alternating treatment including six complete remissions. We concluded that response to the first cycle according to chest X-ray is a reliable and prognostically valid response criterion if sequential therapy is used. In this treatment modality no change in tumor size after the first cycle indicates poor prognosis, and improvement of the patients' outcome may be achieved by a switch to a second non-cross resistant drug combination.

Small cell bronchogenic carcinoma

We have attempted to highlight the most important aspects of SCBC in this review. The significant strides made in a variety of areas have been associated with increased response rates and survival as well as with a prolonged disease-free interval in a fraction of patients. The consensus is that 50% or more of patients with LD can achieve a CR, with an overall objective response rate of 80% or greater and a median overall survival of 14 months or longer. Furthermore, 15% to 20% of such patients may expect a disease-free interval of at least three years that appears to be associated with cure in at least some of these patients. Patients with ED may experience a 20% or greater CR, an 80% or greater objective response, and have a median overall survival of at least seven months. Extensive research is ongoing in a variety of areas. Further refinements in developing more effective chemotherapeutic regimens are likely, as is obtaining new information concerning the intensity, duration, and selection of chemotherapeutic agents and their role in relationship to radiotherapy. Improvement in radiotherapy techniques may lead to improved therapeutic results. Only recently has a reevaluation of the role of surgery in SCBC begun to take place. Also, several new areas of investigation are on the horizon, ranging from improved staging with thoracic and abdominal computed tomography to the role of warfarin, monoclonal tumor antibodies, and several currently investigational chemotherapeutic and biologic response modifier agents.

Vindesine/cisplatin chemotherapy in relapsed or primarily resistant small-cell carcinoma of the lung

Thirty-eight pretreated patients with primarily resistant [6] or relapsed [32] small-cell lung cancer were treated with a combination of vindesine (3-4 mg/m2) and cisplatin (60-100 mg/m2). Eight patients responded to this therapy with three (8%) complete and five (13%) partial remissions. Minor responses were noted in 12 (32%) additional patients. Chemotherapeutic response was rare in regions of prior irradiation. In the complete remission group survival from start of vindesine/cisplatin therapy lasted 61, 48 and 38 weeks, respectively. In the "less-than-complete-remission" group median survival was 12 weeks. Nausea and vomiting were the prominent side-effects, while only mild to moderate myelosuppression was noticed in most cases. The vindesine/cisplatin combination showed significant activity in heavily pretreated small-cell lung carcinoma. However, the remission rates remain low in this unfavourable condition, which might be due to pronounced chemotherapeutic resistance in previously irradiated areas.

Cancer chemotherapy. Current status, coming innovations

A wide number of agents are now available for chemotherapeutic treatment of cancer. The agents fall into four categories: the alkylating agents, the antimetabolites, the anti-tumor antibiotics, and the mitotic inhibitors. Various combinations of the agents are used to gain greater treatment efficacy and reduce resistance, and chemotherapy used as an adjunct to surgery can give added benefit in some cases. Since successful chemotherapy depends on using active drugs, new assays to predict drug responsiveness are being developed. Toxicity of cytotoxic drugs remains a major problem, although attempts at modification hold promise. Clinical trials, the mainstay for evaluating efficacy and toxicity of chemotherapy, must be carefully analyzed to interpret results meaningfully.