Chemotherapeutic results in small cell lung cancer

SCLC-State of the Art and What Does the Future Have in Store?

Worldwide, the total number of diagnosed lung cancer cases amounts to 1.8 million every year. Small-cell lung cancer (SCLC) accounts for about 15% to 17% of all diagnosed lung cancers. Despite all progress made in the field of non-small-cell lung cancer, the prognosis and therapeutic options in SCLC are still limited. The resistance of SCLC to conventional therapy as well as its high recurrence rate can be attributed to the heterogeneous genetic structure of SCLC; however, a targeted therapy approach to SCLC may build on this very heterogeneous genetic structure. SCLC is by now a well-characterized cancer with various genetic alterations; for example, mutations in tumor suppressor genes TP53 and RB1, alterations in chromosome 3p, JAK2, FGFR1, and MYC genes were discovered. Based on these findings, various treatment options (eg, aurora kinase inhibitors, PARP inhibition, immune checkpoint inhibition and vaccine therapy) are currently evaluated with the goal of determining their clinical effectiveness. In this article, we review the existing knowledge of SCLC genetics and the current treatment standards and highlight new approaches of immunotherapy and other targeted therapies, which may yield new treatment options and improve the outcome of patients with SCLC.

The results of treatment in 100 patients with limited-stage small cell lung cancer

BACKGROUND

In an attempt to improve treatment results of small cell lung cancer (SCLC), combined induction chemotherapy and thoracic and prophylactic brain radiation therapy were administered.

METHOD

From December 1980 to December 1987, 112 patients with limited-stage SCLC were treated with combination induction chemotherapy and thoracic or prophylactic brain radiation therapy; 100 were evaluable.

RESULTS

The complete response rate was 40%, and complete and partial responses totaled 94%, with a 5-year survival rate of 23%. There was no difference in remission and survival rates between three-drug and four-drug induction chemotherapeutic regimens. Six chemotherapeutic courses produced longer survival than less therapy. Although the occurrence of brain metastases was no different with or without prophylactic brain radiation therapy, the 3-year survival after this procedure was improved.

CONCLUSION

Treatment of limited-stage SCLC with induction chemotherapy and thoracic and prophylactic brain radiation therapy produced improved remission and survival rates.

[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.

Is there any clinical relevance of serial determinations of serum carcinoembryonic antigen in small cell lung cancer patients?

Carcinoembryonic antigen (CEA) serum concentrations were serially determined by an enzyme immunoassay before, during, and after chemotherapy and radiotherapy in 129 male patients with small cell lung cancer (SCLC). Pretherapeutic CEA concentrations were as follows: 2.5 ng/ml or less for 37% of the patients; greater than 2.5 but less than or equal to 5 for 27%; and greater than 5 for 36%. Before therapy, CEA levels in patients with extensive disease (median value, 5.8 ng/ml) were higher than those in patients with limited disease (3.0 ng/ml; P less than 0.01). Median survival in patients with pretherapeutic CEA titers of 5 ng/ml or less (median survival, 14.3 months) was significantly longer than in patients with CEA levels greater than 5 but less than or equal to 10 and CEA levels greater than 10, respectively (8.3 and 9.7 months; P less than 0.01). Patients with pretherapeutic CEA levels greater than 10 ng/ml showed a significant decrease (P less than 0.01) of CEA while reaching partial remission (PR) or complete remission (CR). In five of 16 evaluable patients, a continuous increase of CEA titers was seen starting at least 3 months before relapse could be defined by clinical, radiologic, or endoscopic means. However, the number of patients for whom CEA serum determinations reliably indicate stage of disease and outcome of therapy is small (at best, 10% of all SCLC patients), and pretherapeutic CEA level cannot be used for individual prognosis. Moreover, it is still uncertain whether earlier detection of relapse in SCLC can improve the therapeutic results. So far, the clinical relevance of serial CEA serum determinations in SCLC patients is rather low.

TNM stage, immunohistology, syntactic structure analysis and survival in patients with small cell anaplastic carcinoma of the lung

TNM stage, immunostaining with various monoclonal and polyclonal antibodies, analysis of distance of neighboring cells, remission rates, and survival were analyzed in 60 patients suffering from small cell anaplastic carcinoma of the lung. The majority of patients showed advanced tumors at the time of admission to hospital (T2, T3 stage). Distant metastases prior to chemotherapy were detected in 34 patients. Partial remissions lasting 2-4 months were observed in 38 patients, and complete remission was documented in 7 patients. The remission rate was independent of cell type but dependent on the stage of the tumor. Some 30 patients showed positive staining with an antibody recognizing epitopes detectable on carcinoembryonic antigen, whereas 60% of the tumors were positive to a polyclonal neuron-specific enolase antibody. Tissue polypeptide antigen was found to stain positively in 5 cases only. Some 14 patients with negative staining against the monoclonal antibody BMA 406/14 showed prolonged survival compared to patients with positive staining (P less than 0.05). Patients suffering from tumors with smaller distances between neighboring cells had worse prognoses compared to patients with larger distances (P less than 0.01). Survival of patients was found to be indistinguishable if cohorts were grouped according to T stage, N stage, or existence of distant metastases. Ten patients who underwent surgical treatment of tumors did not show prolonged survival compared to 50 patients treated by combined chemotherapy only.