Measurement of clinical data in in the experimental and control groups
A total of 173 patients with OE were identified and retrospectively examined. Among these, 21 patients had spontaneously ruptured OE and were considered the experimental group. Of experimental group patients, seven were classified as early stage (I–II), and 15 exhibited advanced disease (III–IV). The 152 unruptured OE cases were defined as the control group; in this group, 59 patients were classified as early stage, while 93 exhibited advanced stage disease.
Both groups were similar in age. In the spontaneously ruptured (experimental) group, the mean age was 33.0±7.3, while in the control group, the mean age was 32.2±6.9. The measurement of CA-125, CA19-9, D-D, FIB, CA-153, and CA-724 levels in the experimental and control groups are shown in Table 1.
In the experimental group, the level of CA-125 was significantly elevated compared to the control group (852.51±1002.71 U/ml vs. 70.53±64.49 U/ml, P < 0.0001). The level of CA19-9 was also significantly elevated in the experimental group (343.09±367.67 U/ml) compared to the control group [36.84±40.01U/ml (P< 0.0001)].
We also measured the expression of D-D and FIB routinely before surgery. For the experimental group, both D-D level and FIB were remarkably increased compared with the control group. To be specific, the experimental group D-D value was 3.39±4.90 mg/L vs. 0.43 ± 0.29 mg/L in the control group (P<0.0001). Meanwhile, the level of FIB was 6.42±6.44 g/L in the experimental group and 2.55±0.58 g/L in the control group (P<0.0001).
The difference of CA-125, CA19-9 levels, and plasma D-D in the experimental and control groups
We subdivided the experimental group into unilateral and bilateral cases. This group was also subdivided into early and advanced disease groups. We then analyzed the levels of CA-125, CA19-9, and D-D according to the various subgroups.
Our results showed no difference in CA-125 levels between the unilateral and bilateral subgroups (884.92±1039.83 U/ml vs. 658.00±892.96 U/ml P=0.796), with similar results for CA19-9 level (369.18±386.250 U/ml vs. 186.52±202.10 U/ml, P=0.503). For plasma D-D, there was no difference between the unilateral and bilateral subgroups (3.56±5.238 mg/L vs. 2.40±2.19 mg/L, P=0.51) (the results were shown in table 2).
When we compared patients with early versus advanced stage disease, we detected no differences in the levels of CA-125, CA19-9, or D-D. To be specific, the level of CA-125 was 960.08 in ±907.93 U/ml (experimental) vs. 786.31±1087.37 U/ml (control; P=0.962), CA19-9 was 427.65±519.979 U/ml (experimental) vs. 291.05±244.72 U/ml (control; P=0.271), D-D was 4.27 ± 5.918mg/L (experimental) vs. 1.98 ± 2.177 mg/L (control; P=0.242) between the two groups (the results were shown in table 2).
Serum CA-125 and CA19-9 levels in the experimental and control groups
We then explored the difference between CA-125 and CA19-9 levels in patients with different stages of unruptured OE, and differences between the unilateral and bilateral subgroups. Both levels of CA-125 and CA19-9 were much higher in the bilateral group compared to the unilateral group; however, the difference of CA-125 showed no significant difference (89.90±67.56 U/ml vs.58.91±59.99 U/ml P=0.095), as showed in Table 3. Meanwhile, the level of CA19-9 was significantly higher in the bilateral group versus the unilateral group (47.09 ±51.72 U/ml vs. 30.69±29.60 U/ml, P=0.036).
The levels of CA-125 and CA19-9 were higher in patients with advanced stage vs. early stage disease. As shown in Table 3, the difference in CA-125 levels was significant (80.00±77.45 U/ml vs. 55.59± 30.71 U/ml, P=0.004), while there was no significant difference in the CA19-9 levels (42.99±44.64 U/ml vs. 27.13± 29.16 U/ml P=0.093).
Performance of serum concentration of CA-125, CA 19-9, and D-D in identifying the spontaneously ruptured OE.
Finally, we applied a ROC curve to assess the importance of serum levels of CA-125, CA 19-9, and D-dimer for differentiating patients with spontaneously ruptured OE. The results were shown in Figure 1A, Table 4, and Supplementary Table 1.
The area under the curve (AUC) showed a statistically significant difference from the null hypothesis (AUC of 0.5), except for OE diameter (shown in Figure 1B and Table 4). To be specific, the AUC for CA-125 was 0.912 (95% CI, 0.859–0.950), while the sensitivity was 85.71, with a specificity of 85.53. The AUC for CA19-9 was 0.918 (95% CI, 0.867–0.955), with sensitivity and specificity of 80.95% and 94.08%, respectively. Besides, the AUC for D-D was 0.924 (95% CI, 0.874–0.959), with a sensitivity and specificity of 85.71% and 81.46%, respectively. The cut-off values of CA-125, CA19-9, and D-D were calculated as 108.1, 95.13, and 0.6, respectively, using MedCal version 19.05. Furthermore, we found the AUC value for the combination of CA19-9 and D-D was 0.975 (95% CI, 0.939–0.993), with the highest specificity of 96.69, and LR+ of 25.89 and LR− of 0.15, while the sensitivity was 85.71. The AUC for the diameter of OE was 0.514 (95% CI, 0.436–0.591), with a sensitivity of 66.67%, and a specificity of 21.33.
We then compared the ROC curves for each marker alone and in combination. The AUC value for CA-125 was G1, the AUC value for CA19-9 was G2, and the AUC value for D-D was G3. The AUC curve of the combined CA-125 and CA19-9, CA-125 and D-D, and CA19-9 and D-D were named G4, G5, and G6, respectively. We concluded that the AUC value for the combined CA19-9 and D-D was significantly higher compared to the AUC value of CA-199, CA-125, and D-D alone, respectively (S Table 1).