Abstract 75P
Background
Leiomyosarcomas (LMS) belong to the group of soft tissue sarcomas (STS) and are one of the most common subtypes, along with liposarcoma (LPS). In the initial stages the gold standard treatment is based on surgery, while the role of chemotherapy (CT) is reserved for advanced stages, although its use has also been studied in the adjuvant and neoadjuvant context, with not enough evidence to support its use in these context. First-line treatment include doxorubicin in monotherapy or in association with other active agents such as gemcitabine, dacarbazine and trabectedin. Other molecules can be used for further lines such as hormone treatment, pazopanib and others.
Methods
We conducted a retrospective, longitudinal and observational study. We reviewed a total of 50 patients with LMS who have received treatment with CT either in the context of adjuvant or metastatic disease. The data was analyzed using the free statistics software Jamovi, using non-parametrical tests for variable associations and frequency measurements for descriptive analysis.
Results
Regarding adjuvant treatment, a total of 26 cases were analyzed, and the relapse rate was 57.6%. Not affected surgical margins was the only factor associated with better OS (50 vs 23 months, p value= 0.005) and RFS (12 vs 3, p value= 0.039). Of the 34 patients with metastatic disease analyzed. Main findings of different regimens and agents of RR, median OF and median PFS are shown in the table. Table: 75P
| Chemotherapy | OR (%) | p value | median OS (months) | p value | median PFS (months) | p value |
| First line: Adriamicine vs gemcitabine | 86 vs 50 | 0.07 | 36 vs 16 | 0.55 | 6 vs 4 | 0.96 |
| Second line: Gemcitabine vs trabectedin | 66 vs 57 | 1.00 | 11 vs 9 | 0.66 | 9 vs 5 | 0.1 |
| Subsequent lines: Gemcitabine Trabectedine Pazopanib | 66 33.3 50 | - - - | 9 6.5 4 | - - - | 6.5 3.5 3 | - - - |
Conclusions
The only factor that was associated with better RFS and OS in patients who received adjuvant treatment with CT was the presence of free surgical margins. First-line treatment with CT in patients with metastatic disease with regimens based on doxorubicin showed more activity compared with others such as gemcitabine, trabectedin, but no statistically significant differences were found. We consider that any of these three agents can be used for patients with metastatic disease.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.