There were total 220 participants including 127 patients in prednisone treatment group (91 females and 36 males; mean age, 41.46 ± 11.65), and 93 patients in control group (73 females and 20 males; mean age, 43.12 ± 11.19). No differences were found between the two groups (P > 0.05). The study compared clinical features associated with thyroid cancer. There was no significantly statistical difference in T stage, N stage, ATA risk classification and pre-ablation Tg between the two groups (all P > 0.05). Details were showed in Table 2.
Table 2
Clinicopathological characteristics of participants
Variables | Control(n = 93) | Prednisone(n = 127) | Statistics | P value |
Age | 43.12 ± 11.19 | 41.46 ± 11.65 | 1.064 | 0.289 |
Gender | | | 1.324 | 0.250 |
Female | 73(78.50) | 91(71.65) | | |
Male | 20(21.51) | 36(28.35) | | |
T stage | | | | 0.755 |
T1a | 40(44.44%) | 53(42.74%) | | |
T1b | 27(30.00%) | 45(36.29%) | | |
T2 | 13(14.44%) | 14(11.29%) | | |
T3 | 9(10.00%) | 9(7.26%) | | |
T4a | 1(1.11%) | 3(2.42%) | | |
N stage | | | 0.039 | 0.980 |
N0 | 6(6.45%) | 9(7.09%) | | |
N1a | 41(44.09%) | 55(43.31%) | | |
N1b | 46(49.46%) | 63(49.61%) | | |
ATA classification | | | 0.306 | 0.858 |
Low | 47(54.02%) | 63(52.94%) | | |
Intermediate | 37(42.53%) | 50(42.02%) | | |
High | 3(3.45%) | 6(5.04%) | | |
Pre-ablation Tg | 2.93(0.65, 6.59) | 2.48(0.68, 8.95) | 5831 | 0.874 |
8–12 months after the initial RAI therapy, combined with TSH-suppressed Tg, TgAb and DxWBS, the response to RAI of participants were evaluated according to 2015 ATA guideline. As Fig. 1 showed the distribution of four responses to RAI therapy in two groups, ER accounted for the largest proportion in both prednisone treatment group and control group, and proportions were 56.69% and 61.29%, respectively. There was no significant difference in the distribution of four kinds of responses to RAI therapy between the two groups (\({\chi }^{2}=1.889\), P=0.596). Furthermore, as Table 3 showed the distribution of four responses to RAI therapy in prednisone treatment group and control group classified by ATA stratification. In ATA low, intermediated, high classification, separately, no significant difference was found in the distribution of four kinds of responses to RAI therapy between prednisone and control groups. Details were showed in Table 3.
Table 3
The distribution of four responses to RAI therapy in prednisone treatment group and control group classified by ATA classification
Variables | Control | Prednisone | Statistics | P value |
ATA-low | 47 | 63 | 0.248 | 0.970 |
ER | 30(63.83%) | 43(68.25%) | | |
IDR | 6(12.77%) | 7(11.11%) | | |
BIR | 4(8.51%) | 5(7.94%) | | |
SIR | 7(14.89%) | 8(12.70%) | | |
ATA-intermediate | 37 | 50 | 4.333 | 0.228 |
ER | 23(62.16%) | 23(46.00%) | | |
IDR | 2(5.41%) | 8(16.00%) | | |
BIR | 6(16.22%) | 6(12.00%) | | |
SIR | 6(16.22%) | 13(26.00%) | | |
ATA-high | 3 | 6 | . | 0.500 |
ER | 0(0.00%) | 3(50.00%) | | |
BIR | 2(66.67%) | 2(33.33%) | | |
SIR | 1(33.33%) | 1(16.67%) | | |
After receiving radiotherapy 2–3 months, participants received a questionnaire of adverse reactions (additional Table 1). Compared with the control group, the proportion of parotid enlargement in prednisone treatment group was lower (25.98% VS 39.78%, P = 0.030). The distribution of gastrointestinal reaction severity was different between the two group (P = 0.010). Patients in prednisone treatment group had higher proportion of no gastrointestinal reaction (70.08% VS 52.69%) and the proportion of moderately gastrointestinal reaction was lower in prednisone treatment group compared with the control group (3.15% VS 10.75%). Details were showed in Table 4.
Table 4
Adverse reactions of RAI compared between PTC patients with and without application of prednisone
| Control (n = 93) | Prednisone (n = 127) | \({\chi }^{2}\) | P value |
Fatigue | | | 0.056 | 0.972 |
No | 56(60.22) | 76(59.84) | | |
Yes | 36(38.71) | 50(39.37) | | |
Parotid enlargement | | | 4.713 | 0.030 |
No | 56(60.22) | 94(74.02) | | |
Yes | 37(39.78) | 33(25.98) | | |
Retroauricular edema | | | 0.002 | 0.964 |
No | 87(93.55) | 119(93.70) | | |
Yes | 6(6.45) | 8(6.30) | | |
Pharyngeal | | | 7.463 | 0.058 |
None | 72(77.42)a | 106(83.47)a | | |
Globus pharyngeus | 4(4.30)a | 6(4.72)a | | |
Pain | 8(8.60)a | 13(10.24)a | | |
Dysphagia | 5(9.68)a | 2(1.57)b | | |
Thirst | | | 1.110 | 0.292 |
No | 62(66.67) | 93(73.23) | | |
Yes | 31(33.33) | 34(26.77) | | |
Dysgeusia | | | 0.290 | 0.590 |
No | 62(66.67) | 89(70.08) | | |
Yes | 31(33.33) | 38(29.92) | | |
Sour | 11 | 5 | | |
Sweet | 11 | 9 | | |
Salty | 31 | 38 | | |
Gastrointestinal reaction | | | 9.129 | 0.010 |
No | 49(52.69)a | 89(70.08)b | | |
Mild | 34(36.56)a | 34(26.77)a | | |
Moderate | 10(10.75)a | 4(3.15)b | | |
Menstruation | | | 0.044 | 0.834 |
Eumenorrhea | 36(73.47) | 43(71.67) | | |
Abnormal | 13(26.53) | 17(28.33) | | |
The study also compared start time and duration time of adverse reactions for RAI in the two groups of participants. The start time of all adverse reactions including fatigue, parotid enlargement, retroauricular edema, pharyngeal symptoms, thirst, dysgeusia and gastrointestinal reaction happened were the first day after RAI. When compared duration time between the two group, the duration of gastrointestinal reaction in the prednisone treatment group was shorter than that in the control group (3 days VS 4 days, P = 0.045).
Until the end of the follow-up of adverse reactions (after receiving radiotherapy 2–3 months), some of adverse reactions in some patients like fatigue (25/220, 11.36%), parotid enlargement (5/220, 2.27%), syndrome of pharynx (17/220, 7.72%), syndrome of thirst (5/220, 2.27%) and dysgeusia (13/220, 5.91%) were not disappeared. Details were showed in Table 5.
Table 5
Start time and duration time of adverse reactions for RAI compared between PTC patients with and without application of prednisone
Variables | Start time | Duration time |
Control | Prednisone | | Control | Prednisone | W | P value |
Fatigue (n = 88) | 1 | 1 | | 15(7, 30) | 30(7, ∞) | 905 | 0.744 |
Parotid enlargement (n = 70) | 1 | 1 | | 7(3, 7) | 5(3, 21) | 625.5 | 0.863 |
Retroauricular edema (n = 14) | 1 | 1 | | 2.5(2, 6) | 5(3, 7.75) | 18.5 | 0.514 |
Pharyngeal symptoms (n = 44) | 1 | 1 | | 7(7, ∞) | 21(7, ∞) | 231.5 | 0.807 |
Thirst (n = 65) | 1 | 1 | | 30(7, ∞) | 10(7, ∞) | 601.5 | 0.317 |
Dysgeusia (n = 69) | 1 | 1 | | 30(12, 30) | 20(10.30) | 556.5 | 0.670 |
Gastrointestinal reaction (n = 83) | 1 | 1 | | 4(3, 7) | 3(1, 7) | 1075 | 0.045 |