ESMO Congress 2023 | OncologyPRO

Abstract 1961P

Background

Sarcomas are rare malignant tumors and represent a heterogeneous group of tumors. An accurate diagnosis of histology is important for treatment strategies. We assessed the pathological review of all patients diagnosed with sarcoma at Siriraj Hospital over a 5-year period to identify the number of first diagnoses compared to the central expert review.

Methods

Histological data from patients diagnosed with sarcoma at Siriraj Hospital were collected over a 5-year period. The initial diagnoses were compared with a certified soft tissue and bone tumor pathologist.

Results

Of the 185 selected patients, 107 (57%) met the inclusion criteria and were analyzed. Full concordance between primary diagnosis and second opinion (the first pathologist and expert reached identical conclusions) was observed in 35 (32.7%) cases, partial concordance (identical diagnosis of connective tumor but different grade or histological type) in 12 (11.2%) cases, and complete discordance (benign versus malignant, different histological type, or invalidation of the diagnosis of sarcoma) in 60 (56.1%) cases. The rate of discordance was higher in incomplete initial IHC (p = 0.003), private laboratory, grade 2 and 3, tumor size ≥ 100 mm (p = 0.01) and age >18. The most common 'full concordance' histology is osteosarcoma (100%, 4 of 4). The main discrepancies were related to histological type (n = 60, 56.1%), subtype (n = 8, 7.5%), and grade plus subtype (n = 4, 3.7%). The mean duration from diagnosis to treatment was 96 days. Only the complete initial report appeared different in the subgroup <97 days group 39 (73.6%) and 97 days group 14 (26.4%) (p=0.03).

Conclusions

More than 65% of the first histological diagnoses were modified in the second reading, possibly resulting in different treatment decisions. The second opinion of the expert improves the quality of diagnosis and possibly the treatment of patients.