Clinical significance of the pathological type of tumor in common forms of ovarian cancer: A retrospective study

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Introduction

Epithelial forms of ovarian cancer account for up to 90% of all ovarian malignancies [1]. Epithelial forms of ovarian cancer are classified according to the WHO criteria of 2014 into several types: the most common are serous carcinomas (70%), mucinous carcinomas (3%), endometrioid tumors (10%), light cell cancer, transitional cell cancer, mixed and undifferentiated carcinomas are rare [2, 3, 4].
According to the molecular genetic subtype, ovarian cancer is divided into type I and type II tumors. Type I tumors are characterized by low malignant potential, are more often asymptomatic and are detected at early stages. They include highly differentiated serous, mucinous, endometriodic and light-cell tumors, malignant Brenner tumor [5]. Type II tumors include low-grade serous, endometrioid, mixed and undifferentiated tumors. Often, the disease is detected at a late stage, has pronounced genetic instability and an unfavorable course [6].
One of the important prognostic factors is the prevalence of the tumor process. The five-year survival rate of patients with ovarian cancer of the initial stages with a high degree of tumor differentiation reaches 90%, but the presence of prognostically unfavorable factors reduces the five-year survival rate to 50% [7]. The five-year survival rate of patients with advanced forms of ovarian cancer reaches 5-20% [8].
The aim is to study the overall survival and progression–free survival depending on the stage of the disease, the pathologic-anatomical type of tumor and the degree of differentiation of tumor cells.
Materials and methods
A retrospective analysis of the treatment of 467 patients with stage IIIC-IVB ovarian cancer in the Primorsky Krai Oncological Dispensary for the period from 2003 to 2021 was carried out. The obtained parameters were processed using standard statistical analysis methods using the IBM SPSS Statistics 26 program.

Results and discussion

The case histories of 467 patients with stage IIIC-IVB ovarian cancer treated at the Primorsky Krai Oncological Dispensary in the period from 2016 to 2021 were subjected to a retrospective analysis. According to the histological structure, the patients were divided as follows: the largest group consisted of patients with serous ovarian cancer high-grade 345/467 (73.9%), with serous ovarian cancer low-grade 60/467 (12.8%), patients without indication of the degree of differentiation 47/467 (10.0%), patients with endometrioid carcinoma 4/467 (0.8%), with mucinous , light - cell and malignant Brenner 's tumor – 5/467 (1,1%), 2/467 (0,4%) and 1/467 (0.2%), respectively (Fig.1).

 

 

 

The overall survival of ovarian cancer patients, depending on the pathologic and anatomical type of tumor, is shown in Figure 2. Significantly worse overall survival rates among patients with stage IIIC-IVB were noted in the group of patients with mucinous cancer – the median overall survival was 4.0±5.5 months. HR 7.7 (95% CI 2.8 – 21.0).

 

Figure 2 – Overall survival of patients with ovarian cancer IIIC–IVB depending on histological type (Kaplan-Meyer assessment)

Median progression-free survival in the high-grade serous cancer group was 18±1.0, significantly worse indicators in the group of patients with low–grade serous ovarian cancer were 19.0±3.9 months, OR 0.7 (95% CI 0.5 - 0.9) and in the group of patients without indication of the degree of differentiation 28.0±4.5 months, OR 0.7 (95% CI 0.5 – 0.9) (Fig.3).

Figure 3 – Progression–free survival of patients with stage IIIC-IV ovarian cancer depending on histological type (Kaplan-Meyer assessment)

 

When determining the status of the BRCA1/2 mutation in patients, it was revealed that patients with the presence of the BRCA 1 mutation have the best overall survival rates – 70.0±10.6, compared to patients with a negative mutation status or untreated for the mutation 45.0±5.2 months, HR 1.7 (95% CI 1.2 – 3.2) and 45.0±6.0 months., HR 1,9 (95% CI 1,2 – 3,1), respectively (Fig.4). When analyzing progression-free survival, no significant differences were obtained in the groups.

 

Figure 4 – Overall survival of patients with ovarian cancer of stage IIIC–IVB depending on BRCA1, BRCA2 mutations (Kaplan-Meyer estimate)

The analysis of overall survival and progression-free survival in patients, depending on the timing of surgical treatment, was carried out. Patients who underwent surgical treatment in full or optimal volume at the first stage have an advantage in overall survival rates at 55 months and progression–free survival at 23 months relative to patients who underwent surgery after neoadjuvant chemotherapy (Fig.5,6).

 

Figure 5 – Overall survival of patients with stage IIIC-IVB in depending on the type of operation, detailed gradation (Kaplan-Meyer evaluation)

Figure 6 – Progression–free survival of stage IIIC-IV patients, depending on the type of surgery, detailed grading (Kaplan-Meyer assessment)

The overall results showed that the most favorable course of stage IIIC-IVB ovarian cancer has a serous type of ovarian cancer, probably due to its sensitivity to chemotherapy and aggressive surgical tactics. Patients with a mutation in the BRCA1/2 genes have a better prognosis in overall survival rates. BRCA1/2 mutations are associated with an improved response to chemotherapy with platinum-based drugs [9].
To date, according to clinical recommendations, all patients with newly diagnosed ovarian cancer should begin treatment with surgery, as well as patients with serous and endometrioid types of ovarian cancer, testing for the presence of mutations in the BRCA1/2 genes is mandatory [10, 11].

Conclusion

Ovarian cancer is a disease that most often proceeds asymptomatically, is diagnosed at late stages and has an unfavorable prognosis. The analysis made it possible to determine the most favorable prognostic factors for advanced stages of ovarian cancer, when comparing the groups of high-grade and low-grade III–IV stage serous carcinoma, it was noted that the median overall survival, depending on the histological type, is better in the group of patients with low-grade III–IV stage serous carcinoma. When comparing, depending on the timing of the operation performed, it can be noted that the median overall survival and median progression-free survival rates are better in the group of patients who received primary cytoreductive surgery.

About the authors

Varvara N. Zhurman

Primorsky Regional Oncological Dispensary; Pacific State Medical University

Author for correspondence.
Email: varvara2007@yandex.ru
ORCID iD: 0000-0002-6927-3336
SPIN-code: 1781-0007

Candidate of Medical Sciences, oncologist-gynecologist of the oncological gynecological department

Russian Federation, st. Russkay 63A, 690000 Vladivostok; Vladivostok

References

Supplementary files