Radiotherapy may improve survival of ES-SCLC with distant metastasis only for patients with one metastatic site: A population-based study

Factors associated with overall survival, progression-free survival and toxicity in patients with small cell lung cancer and thoracic irradiation in a clinical real-world setting

BACKGROUND

Small-cell lung cancer (SCLC) is a malignant tumor known for its poor prognosis. In addition to chemotherapy and immunotherapy irradiation plays a big role especially in inoperability. This study evaluated prognostic factors in patients with SCLC, receiving chemotherapy and thoracic irradiation, that may affect overall survival (OS), progression-free survival (PFS) and toxicity.

METHODS

Patients with limited disease (LD) SCLC (n = 57) and extensive disease (ED) SCLC (n = 69) who received thoracic radiotherapy were analyzed retrospectively. The prognostic factors sex, age, Karnofsky performance status (KPS), tumor-, nodal-stage and timepoint of start of irradiation in relation to the first cycle of chemotherapy were evaluated. Start of irradiation was stratified as early ([Formula: see text] 2 cycles of chemotherapy), late (3 or 4 cycles) and very late ([Formula: see text] 5 cycles). Results were analyzed by Cox univariate and multivariate as well as logistic regression analysis.

RESULTS

The median OS of LD-SCLC patients was 23.7 months in early, and 22.0 months in late start of irradiation. In very late start, median OS was not reached. PFS was 11.8, 15.2 and 47.9 months, respectively. In patients with ED-SCLC OS was 4.3 months in early, 13.0 months in late and 12.2 months in very late start of irradiation. PFS was 6.7, 13.0 and 12.2 months, respectively. Prognosis of patients with LD- or ED-SCLC receiving late or very late start of irradiation was significantly prolonged in OS and PFS compared to an early start (p < 0.05). KPS [Formula: see text] 80 shows a significant increase of OS and PFS in ED-SCLC. Female sex and smaller mean lung dose were associated with lower risk of toxicity.

CONCLUSION

Late or very late start of irradiation is a prognosis-enhancing factor in LD-SCLC and ED-SCLC for OS and PFS. KPS [Formula: see text] 80 increases prognosis of OS and PFS in ED-SCLC as well. Toxicity is less common in female sex and patients with low mean lung dose in LD-SCLC.

Clinicopathological Difference and Survival Impact of Patients with c-SCLC and SCLC

Background

Combined small cell lung cancer (c-SCLC) distinguishes itself from small cell lung cancer (SCLC) due to its inclusion of both SCLC and non-small cell lung cancer (NSCLC) components. Few studies have compared clinicopathological characteristics, prognosis and factors affecting survival. We therefore addressed the issues in this study.

Patients and Methods

A total of 400 c-SCLC and 20,841 SCLC patients were enrolled using SEER database. Difference in clinicopathological characteristics of SCLC and c-SCLC patients was analyzed using chi-square. Kaplan–Meier was applied to compare their survival before and after propensity score matching (PSM). Cox regression model was adopted to assess the impact of different clinical variables on survival. Logistic regression was applied to identify risk factors for c-SCLC and SCLC patients.

Results

Differences in race, sex, T stage, N stage, surgery, bone, brain and liver metastasis were detected between c-SCLC and SCLC patients. c-SCLC patients had better overall survival (OS) than SCLC patients before PSM. Age, race, sex, T stage, N stage, surgery, bone, brain, liver and lung metastasis were prognostic factors affecting OS for c-SCLC and SCLC (P < 0.05). However, a significant OS benefit was not observed in c-SCLC after adjusting for clinicopathological variables (HR, 0.950; 95% CI, 0.842–1.073; P=0.411). No significant OS difference was found between c-SCLC and SCLC patients after PSM (P = 0.789). c-SCLC patients had lower risk of lymph node (OR: 0.555; 95% CI: 0.439–0.703; P < 0.001) and liver metastasis (OR: 0.591; 95% CI: 0.448–0.779; P < 0.001), whereas had no significant differences in bone and brain metastasis risks (P > 0.05) compared with SCLC patients.

Conclusion

The prognosis of c-SCLC did not significantly differ from that of SCLC if clinicopathological characteristics are controlled. Better prognosis for c-SCLC patients over SCLC patients may be ascribed to fewer liver and lymph node metastases upon diagnosis.

Current progress and mechanisms of bone metastasis in lung cancer: a narrative review

Lung cancer is a kind of malignant tumor with rapid progression and poor prognosis. Distant metastasis has been the main cause of mortality among lung cancer patients. Bone is one of the most common sites. Among all lung cancer patients with bone metastasis, most of them are osteolytic metastasis. Some serious clinical consequences like bone pain, pathological fractures, spinal instability, spinal cord compression and hypercalcemia occur as well. Since the severity of bone metastasis in lung cancer, it is undoubtedly necessary to know how lung cancer spread to bone, how can we diagnose it and how can we treat it. Here, we reviewed the process, possible mechanisms, diagnosis methods and current treatment of bone metastasis in lung cancer. We divided the process of bone metastasis in lung cancer into three steps: tumor invasion, tumor cell migration and invasion in bone tissue. It may be influenced by genetic factors, microenvironment and other adhesion-related factors. Imaging examination, laboratory examination, and pathological examination are used to diagnose lung cancer metastasis to bone. Surgery, radiotherapy, targeted therapy, bisphosphonate, radiation therapy and chemotherapy are the common clinical treatment methods currently. We also found some problems remained to be solved. For example, drugs for skeletal related events mainly target on osteoclasts at present, which increase the ratio of patients in osteoporosis and fractures in the long term. In all, this review provides the direction for future research on bone metastasis in lung cancer.