This study is one of the largest retrospective series of OCCC patients in which data were collected from patients at diagnosis to second recurrence. We mainly described the stage composition, recurrence status, and PFS of OCCC patients and found that FIGO stage and chemotherapy resistance are independent risk factors for prognosis. We also aimed to explain the limitations associated with CA-125 in the staging and recurrence monitoring of OCCC. The limitations of CA-125 in patients with FIGO stage I and those who experience recurrence are highlighted.
Among the 112 patients included, 53.57% were in stage I and 28.57% were in stage III, which is similar to the results of a national study performed in South Korea2 but quite different from other single-centre studies6 7. All patients underwent staging or cytoreductive surgery. Except for one patient who refused chemotherapy after surgery, all the other patients received platinum chemotherapy drugs. Approximately 1/4 of patients in stage III/IV receive advanced chemotherapy, although we found that advanced chemotherapy is not beneficial to prognosis. It is worth noting that the one-year PFS rate of patients with stage I, II and III disease was approximately 90%, and the three-year PFS rate varied greatly, with 86.44% for patients in stage I, 66.67% for patients in stage II, and 66.67% for patients in stage III 56.67%. These three indicators were slightly higher than the national research data of South Korea. Staging has been confirmed as a risk factor for the prognosis of OCCC in many studies, so I will not repeat it here. OCCC patients with platinum-resistant recurrence had a shorter PFS duration than those with platinum-sensitive recurrence (8 months vs 19 months). The median survival duration with single-agent chemotherapy and bevacizumab does not exceed 16 months12. Most other chemotherapy regimens are almost ineffective.11 A recent study summarized the biological rationale and available clinical data on immunotherapy in platinum-resistant ovarian cancer and discussed the challenges and future areas of research in the field13.
In contrast to other studies10 14, we found that the monitoring of CA-125 is of limited significance and has no predictive significance for prognosis.10 14 We previously published a study in which OCCC patients who visited PUMCH between 1993 and 2013 were analysed and found that CA-125 levels following treatment were a valid indicator for treatment monitoring10. Although the same method was used, in the current study, we obtained a negative result, that is, the normalization of CA-125 levels before 2 cycles of chemotherapy does not affect PFS or OS. This may be because the samples we collected are different. In addition, we found that 61.11% of stage I patients had CA-125 levels in the normal range when they first became ill. During treatment, there was no difference in the number of courses of chemotherapy or prognosis between these patients and other stage I patients, and 72.73% of these patients had normal CA-125 levels after surgery or 1 course of chemotherapy. Therefore, we believe that for patients who are not sensitive to the CA-125 test the first time, ultrasound, CT or MRI should be considered first. Importantly, an examination can reduce the disease burden on patients. In contrast to stage I patients, 76.67% of stage III patients had CA-125 levels greater than 35 IU/ml. We believe these patients are more suitable for CA-125 monitoring. Moreover, 50% of patients who experienced recurrence had CA-125 levels in the normal range, which further showed that monitoring CA-125 levels is of limited significance and may delay the discovery of recurrence.
We verified the value of Napsin A and HNF1B in the diagnosis of OCCC by calculating the false positive rate. In 2013, Skirnisdottir I15 proposed that the positivity of Napsin A is helpful for the diagnosis of OCCC. In 2020, Fatemeh Nili16 reported that the sensitivity of Napsin A in the diagnosis of OCCC was 85%. However, we found that 39.62% of patients were still negative for Napsin A. Only 15% of patients were negative for HNF1B, which is consistent with Wenbin Huang's findings17. We combined the two indicators and found that the false positive rate was 9%. It is also worth noting that patients who were in remission had a shorter follow-up time than patients who relapsed (22.50 vs 33.00), (not shown in the table due to space reasons). There is no doubt that disease monitoring has been gradually relaxed in these patients. We believe that clinicians should provide patients with continuous follow-up to detect disease recurrence in advance and intervene as soon as possible.
The patients included in the current study were from economically developed areas in China, and they had satisfactory economic and medical conditions, which suggests that in poor areas in China, the accessibility of treatment and prognosis may be worse. Due to the habit of case writing, clinicians are accustomed to recording key CA-125 values, such as preoperative CA-125 values and chemotherapy cycles of CA-125 normalization. CA-125 values that do not exhibit major changes, such as those after each chemotherapy procedure, cannot be obtained and are thus not conducive to our discussion of the monitoring value of CA-125.