Study Characteristics
The systematic review resulted in 806 articles with 351 screened after duplicates were removed (Figure 1). Following the criteria described above, a total of 305 studies were excluded. Forty-six full-text articles were assessed. Among them, 26 were excluded as they conducted adjuvant therapy studies and did not provide relevant outcomes. Twenty different studies fulfilled the predefined inclusion criteria. The main details of the included articles are shown in Table 1.
No randomized control trials were available to be included in this review. Two studies met the criteria as good quality studies. The remaining 18 studies were of poor quality(Table 2.).