(P 155) PRIMARY MESENCHYMAL TUMORS OF THE HEART: A 8-YEARS, SINGLE INSTITUTION EXPERIENCE

Objective: Heart tumors represent an ultra-rare and heterogeneous category of neoplasms, with an incidence ranging between 0.001 and 0.28 %. Among the primary cardiac neoplasms, only 20% are malignant, with sarcomas comprising 95% of these cases.
The management of primary cardiac sarcomas represents a formidable challenge for the cardiothoracic surgery, medical oncology and radiation oncology communities alike.
Considering these assumptions, we aim to retrospectively analyzed clinical, pathological and survival data of 17 patients (pts) with primary cardiac mesenchymal tumors diagnosed between 2015 and 2023 and evaluated at our center, Humanitas Research Hospital, Rozzano (MI), Italy.

Methods: We collected data from the pathology archive, encompassing all diagnoses of primary cardiac mesenchymal tumors either treated or reviewed at our Institute. Data analyzed included medical history, pathologic details, treatments and outcome.
Each patient underwent a complete cardiologic and radiologic assessment at diagnosis, including transthoracic/transesophageal echocardiography, cardiac magnetic resonance imaging (MRI) and a chest-abdomen CT scan in order to characterize both the local and distant extent of disease.
All the cases were evaluated in a sarcoma-dedicated multidisciplinary board in order to devise the most suitable therapeutic approach for each patient.
Survival analysis was performed using Kaplan-Meyer Survival curves.

Results: The cohort of primary cardiac mesenchymal tumors included 16 cardiac sarcomas (8 females and 8 men) and 1 mesenchymal neoplasm without evidence of malignancy, with a median age at diagnosis of 50 years (range 25-76).
The histological subtypes were as follows: angiosarcoma (4, 23%), intimal sarcoma (6, 35%), leiomyosarcoma (1, 6%), malignant peripheral nerve sheath tumor (MPNST) (1, 6%), pleomorphic rhabdomyosarcoma (1, 6%), extra-skeletal Ewing sarcoma (1, 6%), monophasic synovial sarcoma (1, 6%), low-grade sarcoma (1, 6%), mesenchymal neoplasm without evidence of malignancy (1, 6%). (Table 1).
At diagnosis, localized disease was detected in 8/17 pts (47%), while 6/17 (35%) cases had locally-advanced-disease and the remaining 3/17 pts (18%) had distant metastasis.Cardiac surgery was performed in 10 out of 17 pts (59%) and in 9/10 cases resulted in R1 margins. One patient underwent emergency surgery with R2 margins.
A second cardiac resection was feasible in 3/10 pts when they experienced local relapse in the heart.

Chemotherapy was administered to 13 out of 17 pts: 3/13 (23%) received adjuvant treatment, with a disease-free interval (DFI) of 14, 5 and 11 months, respectively; 2/13 (15%) were treated with cytoreductive chemotherapy (that was achieved in one case of intimal sarcoma of the pulmonary artery) and 8/13 (62%) underwent palliative chemotherapy.
Treatment strategies and responses are summarized in Table 2.

3/17 (18%) pts received cardiac radiotherapy (2 with adjuvant intent and 1 for palliative purpose).

Follow-up data was available for 16/17 pts, with a median follow-up of 13,50 months and a median overall survival (OS) of 18 mo. (95% CI 11-43). (Figure 1).
At the time of our analysis, 11/16 (69%) pts had died due to disease; 2/16 (12%) pts were alive with disease at 17 and 9 months from the diagnosis, while 3/16 pts (19%) were alive with no evidence of disease after surgical resection, with survival of 15, 16 and 12 months, respectively.

Conclusion: According to literature data, PCS represent an ultrarare disease with a dismal prognosis.
Our findings argue for the importance of referral of cardiac sarcoma pts to high-volume centers. Considering the specific primary sites of PCS, their variable clinical manifestations and the difficulties in achieving an R0 resection, the only modifiable factor remains the multidisciplinary management of the disease.