Table 2.

Patients' treatment, outcome and CTCs counting and characterization.

Patient ID	Histological subtype	Positivity ratio EGFR	Number of EGFR positive CTCs in 1ml of blood	Number of EGFR negative CTCs in 1ml of blood	CTC/1ml	CTM	Collection before the first-line treatment	Treatment received after CTC collection	Line of treatment
1	Pleomorphic Sarcoma	1	4	0	1.25	–	Yes	Gemcitabine + Docetaxel	1st
2	Rhabdomyosarcoma	1	3	0	1	–	Yes	Ifosfamide + Doxorubicin	1st
3	Liposarcoma	1	5	0	11.25	+	Yes	Doxorubicin Monotherapy	1st
4	Synovial Sarcoma	0.7	5	1	4	+	Yes	Ifosfamide + Etoposide	1st
5	Pleomorphic Sarcoma	1	2	0	4.5	+	Yes	Epirubicin + Ifosfamide	1st
6*	Leiomyosarcoma	1	1	0	0.75	–	No	Ifosfamide + Etoposide	2nd
7*	Pleomorphic Sarcoma	0.1	2	12	6.25	+	No	Dacarbazine + Gemcitabine	3rd
8	Leiomyosarcoma	0.8	5	1	2	–	Yes	Ifosfamide + Doxorubicin	1st
9*	Leiomyosarcoma	0.3	1	2	0.75	–	No	Doxorubicin + Dacarbazine	2nd
10	Synovial Sarcoma	0	0	7	2	–	No	Ifosfamide	2nd
11	Synovial Sarcoma	1	2	0	1	–	Yes	Epirubicin + Ifosfamide	1st
12	Leiomyosarcoma	1	1	0	0.93	–	Yes	Dacarbazine Monotherapy	1st
13	Synovial Sarcoma	–	–	–	0	–	Yes	Ifosfamide + Doxorubicin	1st
14	Synovial Sarcoma	0.5	1	1	1.87	–	No	Ifosfamide	2nd
15	Leiomyosarcoma	0.5	2	2	9.6	–	No	Epirubicin + Ifosfamide	2nd
16	Synovial Sarcoma	–	–	–	0	–	No	Ifosfamide	3rd
17	Synovial Sarcoma	0.5	2	2	5	+	Yes	Epirubicin + Ifosfamide	1st
18	Pleomorphic Sarcoma	0.5	2	2	5.66	–	No	Doxorubicin	2nd

Positivity Ratio: The positivity ratio of EGFR was calculated as the number of EGFR-positive CTCs present on ISET membrane spot divided by the total CTCs present in the same spot.

CTC count per mL of blood: CTCs were counted in four spots of the membrane, which corresponds to 4 mL blood. After counting we calculated the mean of these four spots to obtain the amount of CTCs per1 mL of blood, according to Krebs et al. (2012).¹⁵

^*patients that underwent resection of primary tumor and metastasis in first line treatment were excluded from the progression-free survival analysis.