Cisplatin plus oral etoposide in the treatment of patients with advanced small cell lung cancer. Japan Clinical Oncology Group

History of Japan Clinical Oncology Group (JCOG) Lung Cancer Study Group

The Japan Clinical Oncology Group Lung Cancer Study Group has been carrying out clinical studies, exploring new strategies of treatment, supportive therapies (antiemetics, etc.), etc., for a variety of cancers, including not only small cell lung cancer and non-small cell lung cancer but also rare chest tumours (represented by thymoma) and cancer-associated conditions (cancerous pericarditis, cancerous pleuritis, etc.). In this review, an overview of all studies conducted from 1985 to 2019 is provided.

A systematic review of survival following anti-cancer treatment for small cell lung cancer

OBJECTIVES

We conducted a systematic review and meta-analysis of survival following treatment recommended by the European Society of Medical Oncology for SCLC in order to determine a benchmark for novel therapies to be compared with.

MATERIALS AND METHODS

Randomized controlled trials and observational studies reporting overall survival following chemotherapy for SCLC were included. We calculated survival at 30 and 90-days along with 1-year, 2-year and median.

RESULTS

We identified 160 for inclusion. There were minimal 30-day deaths. Survival was 99 % (95 %CI 98.0-99.0 %, I²33.9 %, n = 77) and 90 % (95 %CI 89.0-92.0 %, I²79.5 %, n = 73) at 90 days for limited (LD-SCLC) and extensive stage (ED-SCLC) respectively. The median survival for LD-SCLC was 18.1 months (95 %CI 17.0-19.1 %, I²77.3 %, n = 110) and early thoracic radiotherapy (thoracic radiotherapy 18.4 months (95 %CI 17.3-19.5, I²78.4 %, n = 100)) vs no radiotherapy 11.7 months (95 %CI 9.1-14.3, n = 10), prophylactic cranial irradiation (PCI 19.7 months vs No PCI 13.0 months (95 %CI 18.5-21.0, I²75.7 %, n = 78 and 95 %CI 10.5-16.6, I²81.1 %, n = 15 respectively)) and better performance status (PS0-1 22.5 months vs PS0-4 15.3 months (95 %CI 18.7-26.1, I²72.4 %, n = 11 and 95 %CI 11.5-19.1 I²77.9 %, n = 13)) augmented this. For ED-SCLC the median survival was 9.6 months (95 %CI 8.9-10.3 %, I²95.2 %, n = 103) and this improved when irinotecan + cisplatin was used, however studies that used this combination were mostly conducted in Asian populations where survival was better. Survival was not improved with the addition of thoracic radiotherapy or PCI. Survival for both stages of cancer was better in modern studies and Asian cohorts. It was poorer for studies administering carboplatin + etoposide but this regimen was used in studies that had fewer patient selection criteria.

CONCLUSION

Early thoracic radiotherapy and PCI should be offered to people with LD-SCLC in accordance with guideline recommendations. The benefit of the aforementioned therapies to treat ED-SCLC and the use of chemotherapy in people with poor PS is less clear.

Extensive disease small cell lung cancer dose-response relationships: implications for resistance mechanisms

BACKGROUND

Some studies (but not others) suggested that high doses are beneficial in small cell lung cancer (SCLC). We hypothesized that dose-response curve (DRC) shape reflects resistance mechanisms.

METHODS

We reviewed published SCLC clinical trials and converted response rates into estimated mean tumor cell kill, assuming killing is proportional to reduction in tumor volume. Mean % cell survival was plotted versus planned dose intensity. Nonlinear and linear meta-regression analyses (weighted according to the number of patients in each study) were used to assess DRC characteristics.

RESULTS

Although associations between dose and cell survival were not statistically significant, DRCs sloped downward for five of seven agents across all doses and for all seven when lowest doses were excluded. Maximum mean cell kill across all drugs and doses was approximately 90%, suggesting that there may be a maximum achievable tumor cell kill irrespective of number of agents or drug doses.

CONCLUSIONS

Downward DRC slopes suggest that maintaining relatively high doses may possibly maximize palliation, although the associations between dose and slope did not achieve statistical significance, and slopes for most drugs tended to be shallow. DRC flattening at higher doses would preclude cure and would suggest that "saturable passive resistance" (deficiency of factors required for cell killing) limits maximum achievable cell kill. An example of factors that could flatten the DRC at higher doses and lead to saturable passive resistance would be presence of quiescent, noncycling cells.