Clinicopathological and Prognostic Features of 67 Cases with Pulmonary Sarcomatoid Carcinoma: An 18-Year Single-Centre Experience

Case report: Pulmonary sarcomatoid carcinoma demonstrating rapid growth on follow-up CT

Background

The tumor growth rate and tumor volume doubling time are crucial parameters in diagnosing and managing lung lesions. Pulmonary sarcomatoid carcinoma (PSC) is a unique and highly malignant subtype of lung cancer, with limited documentation on its growth feature. This article aims to address the gap in knowledge regarding a PSC's growth patterns by describing the characteristics of a confirmed case using computed tomography, thereby enhancing the understanding of this rare disease.

Case presentation

A 79-year-old man was transferred to our center presenting with a mild cough, blood-tinged sputum, and a malignant nodule in the left upper lobe. Chest CT revealed a solid nodule in the left upper lobe. A follow-up CT ten days later showed a significant increase in the size of the nodule, accompanied by ground-glass opacity in the surrounding lung. The rapid preoperative growth of the nodule suggested a non-neoplastic lesion, and intraoperative frozen pathology also considered the possibility of tuberculosis. Subsequently, a left upper apical-posterior segment (S1 + 2) resection was performed. Postoperative tumor pathology confirmed the diagnosis of pulmonary sarcomatoid carcinoma with extensive giant cell carcinoma and necrosis. Immunohistochemistry indicated approximately 60% PD-L1 positive and genetic testing revealed a MET mutation. The patient was discharged with oral crizotinib targeted therapy, and his condition remained stable postoperatively. The patient is currently undergoing regular follow-up at our hospital, with no evidence of distant metastasis or recurrence.

Conclusion

Pulmonary sarcomatoid carcinoma can exhibit rapid tumor growth on imaging, and PSC should be considered in the differential diagnosis for lesions that present with a fast growth rate. Timely and appropriate treatment for PSC may lead to a good prognosis.

Survival analysis and nomogram for pulmonary sarcomatoid carcinoma: an SEER analysis and external validation

OBJECTIVE

Uncommon and particularly deadly, pulmonary sarcomatoid carcinoma (PSC) is an aggressive type of lung cancer. This research aimed to create a risk categorisation and nomogram to forecast the overall survival (OS) of patients with PSC.

METHODS

To develop the model, 899 patients with PSC were taken from the Surveillance, Epidemiology, and End Results database from the USA. We also used an exterior verification sample of 34 individuals with PSC from Fujian Provincial Hospital in China. The Cox regression hazards model and stepwise regression analysis were done to screen factors in developing a nomogram. The nomogram's ability to discriminate was measured employing the area under a time-dependent receiver operating characteristic curve (AUC), the concordance index (C-index) and the calibration curve. Decision curve analysis (DCA) and integrated discrimination improvement (IDI) were used to evaluate the nomogram to the tumour-node-metastasis categorisation developed by the American Joint Committee on Cancer (AJCC-TNM), eighth edition, and an additional sample confirmed the nomogram's accuracy. We further developed a risk assessment system based on nomogram scores.

RESULTS

Six independent variables, age, sex, primary tumour site, pathological group, tumour-node-metastasis (TNM) clinical stage and therapeutic technique, were chosen to form the nomogram's basis. The nomogram indicated good discriminative ability with the C-index (0.763 in the training cohort and 0.746 in the external validation cohort) and time-dependent AUC. Calibration plots demonstrated high congruence between the prediction model and real-world evidence in both the validation and training cohorts. Nomogram outperformed the AJCC-TNM eighth edition classification in both DCA and IDI. Patients were classified into subgroups according to their risk ratings, and significant differences in OS were observed between them (p<0.001).

CONCLUSION

We conducted a survival analysis and nomogram for PSC. This developed nomogram holds potential to serve as an efficient tool for clinicians in prognostic modelling.

Integrated Clinical, Molecular and Immunological Characterization of Pulmonary Sarcomatoid Carcinomas Reveals an Immune Escape Mechanism That May Influence Therapeutic Strategies

Pulmonary sarcomatoid carcinoma (PSC) has highly aggressive biological behaviour and poor clinical outcomes, raising expectations for new therapeutic strategies. We characterized 179 PSC by immunohistochemistry, next-generation sequencing and in silico analysis using a deep learning algorithm with respect to clinical, immunological and molecular features. PSC was more common in men, older ages and smokers. Surgery was an independent factor (p < 0.01) of overall survival (OS). PD-L1 expression was detected in 82.1% of all patients. PSC patients displaying altered epitopes due to processing mutations showed another PD-L1-independent immune escape mechanism, which also significantly influenced OS (p < 0.02). The effect was also maintained when only advanced tumour stages were considered (p < 0.01). These patients also showed improved survival with a significant correlation for immunotherapy (p < 0.05) when few or no processing mutations were detected, although this should be interpreted with caution due to the small number of patients studied. Genomic alterations for which there are already approved drugs were present in 35.4% of patients. Met exon 14 skipping was found more frequently (13.7%) and EGFR mutations less frequently (1.7%) than in other NSCLC. In summary, in addition to the divergent genomic landscape of PSC, the specific immunological features of this prognostically poor subtype should be considered in therapy stratification.

Multimodality Treatment of Pulmonary Sarcomatoid Carcinoma: A Review of Current State of Art

Pulmonary sarcomatoid carcinoma (PSC) is an unconventional non-small-cell lung cancer (NSCLC) that is currently managed under guidelines used for conventional NSCLC and has poor survival. Surgery is the optimal choice for resectable PSC, and the prevalence of mutations in this type of tumor laid the foundation for novel systemic therapies such as targeted therapy and immunotherapy. PSC is resistant to chemotherapy and radiotherapy, and the effects of the 2 therapies are controversial. Targeted therapies have been reported to confer survival benefits, and savolitinib, an oral selective MET tyrosine-kinase inhibitor, has been approved in metastatic patients with MET exon 14 skipping mutations. Expression and positive rate of programmed death ligand 1 in PSC are high; our previous research has also revealed a high mutational burden and a T-cell-inflamed microenvironment of PSC. Correspondingly, immune checkpoint inhibitors have shown preliminary antitumor effects (overall response rates of 40.5% (15/37) and 31.6% (6/19) in two retrospective studies, respectively) in PSC patients. In summary, patients should receive operations at an early stage and multimodality treatments are needed to maximize the benefits of patients with advanced disease.