Table 4 Published studies focusing on the clinical outcomes of patients with relapsing oral cavity cancer according to the relapse interval

Liao et al. (current study)

(2011 − 2017)

16.9% (2327/13,789),

84%/2-year

None

26%/74%

Cox proportional hazards model with spline

≤ 330 days (1630)

/>330 days (697).

After propensity score matching:

≤ 330 days (654)

/>330 days (654)

DSS: relapse interval, age, pN, p-Stage, DOI, distant relapse

OS: relapse interval, male sex, age, pT, pN, poor differentiation, DOI, distant relapse

Propensity score-

matched groups:

DSS: 30%/58%

(p < 0.0001);

OS: 22%/49%

(p < 0.0001)

Liao et al. [5]

(1996 − 2005)

28.5% (272/953)

NR

None

28%/72%

Kaplan-Meier

≤ 10 months (161)

/>10 months (111)

Early relapse (DSS/OS) ^a: p-Stage, poor differentiation, DOI, distant relapse

Late relapse (DSS/OS) ^a: pT, poor differentiation, ENE, distant relapse, neck recurrence

DSS: 14%/54%

(p < 0.0001),

OS: 12%/54%

(p < 0.0001)

Weckx et al. [6]

(2002 − 2015)

23% (159/691)

60%/2-year

< 6 weeks

43%/57%

Every 4 months followed by 1 year

1–4 months (11)

/5–8 months (32)

/9–12 months (15)

/13–24 months (37)

/>24 months (64)

OS: relapse interval, ENE, margins, salvage therapy

OS: 0%/40%/52%/49%

/87%

(p < 0.001)

Liu et al. [7]

(1995 − 2003)

50.5% (648/1282)

NR

< 6 months

54%/46%

ROC curve analysis

< 18 months (239)

/≥18 months (162)

OS: relapse interval, age, p-Stage

Survival after relapse:

28%/38% (p < 0.001)

Schwartz et al. [8]

(1956 − 1992)

28% (99/350)^b

92%/3-year

≤ 3 months

47%/53%

NR

≤ 6 months (11)

/>6 months (27)

NR

Mean survival time:

20/54 months (p, NR)

Mucke et al. [9]

(1992 − 2006)

23.9% (185/773)

71%/3-year

≤ 6 months

46%/54%

ROC curve analysis

≤ 18 months (88)

/>18 months (97)

NR

Survival after relapse:

21%/42% (p = 0.03)