Nomogram is a diagram that represents the relations between three or more variable quantities through multiple scales. Sarculator is an online validated nomogram that predicts overall survival of patients with primary trunk and extremity sarcomas, mostly created using European data from patients treated at high-volume centers.
Between March 18th and 19th, SSO 2021 (International Conference on Surgical Cancer Care) took place in virtual format. During the event, it was presented a study compared the overall survival predicted by the Sarculator nomogram with the overall survival in U.S. patients using the National Cancer Database. Sarculator is an online validated algorithm that predicts the overall survival of patients with sarcomas of the trunk and resected primary extremities, created mainly from European data from individuals treated in high-volume centers. However, its ability to accurately predict outcomes in sarcoma patients in the United States was still unknown.
The trial evaluated 9,738 patients from the National Cancer Database (2006–2016) with primary sarcoma of the extremity or trunk in stage I to III who underwent R0/R1 resection. The predicted overall survival was calculated using the Sarculator algorithm, which includes patient age, tumor size (cm), grade (I – III), and histology. The predicted overall survival was compared to the actual overall survival, and the Harrell’s C index was calculated to determine the discrimination of the predicted overall survival model of the Sarculator (0.7 = good model, 0.8 = strong model, 1.0 = perfect model).
The analysis showed that undifferentiated pleomorphic sarcoma (17%), leiomyosarcoma 15.7%) and myxoid liposarcoma (10.9%) were the most common individual histologies. Of the patients analyzed, 8,829 (90%) underwent R0 resection, 1,599 (16.3%) received chemotherapy and 5,832 (59.5%) received radiotherapy.
The five-year predicted overall survival was 73.7%, compared to an actual overall survival of 68.9%. The C index for the entire cohort was 0.726. By stage, the C index was 0.730 for stage I, 0.708 for stage II, and 0.679 for stage III disease. By histology, the C index was highest for leiomyosarcoma (0.745), myxoid liposarcoma (0.719), and other histologies (0.719), and it was lowest for malignant peripheral nerve sheath tumor (0.656), liposarcoma (0.679), and synovial sarcoma (0.694).
The authors conclude that, overall, Sarculator is a good predictor of actual overall survival for patients with primary trunk and extremity sarcomas in the USA. Sarculator performs slightly better for early stages (I/II) and better for leiomyosarcoma, myxoid liposarcoma and other histologies, being a good clinical tool for surgeons and oncologists to help with prognosis.