Prediction Cause-Specific Mortality for Soft Tissue Cardiac Sarcoma Patients in the United States: A Competing Risk Analysis
Authors: Ahmmad Roungu 
Published: March 2023

Objectives

Several studies have revealed contradictory findings on survival by exposing cancer treatments with disparities of sociodemographic and tumor histologic factors. However, this study aimed to evaluate the effect of cancer treatments on mortality among patients with soft tissue cardiac sarcomas (CS) in the United States. We also estimated the overall survival probability through a competing risk nomogram for this notorious disease.

Methods

The data was taken from the US National Cancer Institute’s Surveillance Epidemiology, and End Results (SEER) -18 dataset, version 2020. Between the years 2000 and 2018. The study cohort included patients diagnosed with soft tissue cancer, including cardiac sarcoma. We computed the cumulative incidence function (CIF) and sub-distributional hazard by the Fine and Gray model for evaluating the risk of mortality. In addition, using a competing-risk nomogram we forecasted the overall survival probability for patients with soft tissue CS. Calibrations and Brier scores were used to validate and compare the prediction to ensure predictive accuracy.

Results

A total of 416 completed cases were selected for evaluation in this study. There was 66.5% mortality from soft tissue CS in the patients during this study period, while there was only 16.3% death from other diseases. For patients with soft tissue CS, the five-year cumulative incidence of cause-specific mortality was 74%, while only 18% was caused by other diseases. Non-whites, older age groups, and more advanced cancer stages all contributed to a higher cause-specific cumulative incidence, but sex was not a significant predictor of soft tissue CS deaths. Patients who underwent surgical intervention [sdHR: 0.55, 95%CI:0.28-0.98] and chemotherapy [sdHR: 0.29, 95%CI:0.02-0.36] on prime site had a significant decrease in CS death compared with no intervention, whereas primary systemic therapy and radiation intervention were not significantly decreased patients mortality. The patients who received surgery on the prime site survived 2, and 5 years above 70%, and 60%, respectively, whereas those who did not receive surgery on the prime site survived only 10%. Nomograms for assessing the hazard of mortality for patients with soft tissue cancers were well calibrated and had a good discriminatory ability.

Conclusion

Despite the small sample size, this study provided a reliable model-based prediction of the effect of cancer treatment on rare malignancies. The use of surgery and chemotherapy significantly reduced patient cause-specific mortality; however, the use of primary systemic treatment and radiation did not significantly reduce patient mortality among patients with soft tissue CS.

Clinical Perspective

What is New?

Patients with soft tissue Cardiac Sarcoma (CS) are more likely to die if they are older, at a distant stage, and have not received treatment.

Among patients with CS, there is no significant association between race, gender, radiotherapy, or primary systemic therapy with mortality

There is a greater reduction in mortality rate associated with chemotherapy and surgical intervention at the primary site than without these interventions.

What are the Clinical Implications?

A competing risk nomogram suggests that soft tissue CS is associated with a lower probability of cause-specific survival than other causes of mortality.

The survival rate for patients who underwent surgery on prime sites was 70%, 55%, after two, and five years, whereas the survival rate for patients who did not undergo surgery was only 10%.

A cause specific nomogram revealed that radiation intervention increases survivability compared to not receiving radiation intervention, and that age, sex, treatment, and cancer stages affected survival.