Table 4 Overview of the characteristics of the 42 trials included in the analysis

Type of neoplasm

Gastrointestinal

9

21.4

Breast

9

21.4

Hematological

6

14.3

Gynecological

4

9.5

Lung

3

7.1

Genitourinary

3

7.1

Skin

3

7.1

Head and neck

2

4.8

Non-specific

3

7.1

Decade of initiation

1980s

2

4.8

1990s

5

11.9

2000s

12

28.6

2010s

23

54.8

Study status

Completed

35

83.3

Ongoing

7

16.7

Protocol availability

Accessible

23

54.8

Inaccessible

19

45.2

Clinical phase

I

2

4.8

I/II

1

2.4

II

9

21.4

II/III

1

2.4

III

7

16.7

IV

1

2.4

N/A

21

50.0

Randomization

Randomized

31

73.8

Non-randomized

5

11.9

Single-arm

6

14.3

Blinding

Blinded

2

4.8

Open-label

40

95.2

Number of study arms

1

6

14.3

2

30

71.4

3 or more

6

14.3

Type of intervention

Pharmacotherapy

24

57.1

Surgery

13

31.0

Radiotherapy

16

38.1

Other

7

16.7

Combination

15

35.7

Type of comparator

Active

34

81.0

Standard of care or equivalent

28

66.7

Placebo

2

4.8

None

7

16.7

Primary endpoint(s)

Overall survival

6

14.3

Quality of life

1

2.4

Surrogate

26

61.9

Secondary endpoint(s)

Overall survival

26

61.9

Quality of life

23

54.8

Surrogate

36

85.7

Site-level setting

Monocentric

11

26.2

Multicentric

31

73.8

Country-level setting

National

29

69.0

International

13

31.0

Legal sponsorship

By industry

3

7.1

By other party

39

92.9

Funding source

Commercial

15

35.7

Non-commercial or academic

27

64.3

Median

IQR

Study duration (in years)

5.5

3–8

Impact factor journal of publication

9.162

4.853–41.316

Number of participants

Phase II trials

68

51–121

Phase III trials

501

231.5–748

Overall

161

87.5–538.5