According to the results of our study, in patients with advanced ovarian, tubal and peritoneal epithelial cancer, involvement of the hilus and capsule was found to be the most common sites of the splenic involvement. It was observed that the effects of involvement of different parts of the spleen on the overall survival were different. The treatment of ovarian cancer depends on multifactorial features that include the stage of the disease, performance status of the patient and tumor features and some other clinical factors. Also, the complete resection of all macroscopic disease at primary debulking surgery has been shown to be the single most important independent prognostic factor in advanced disease . For this reason, the surgical management for optimal treatment of ovarian cancer shifted in recent years from surgical resection of pelvic organs to a major surgery involving the upper abdomen. Brislow et al. showed that a 10% increase in cytoreduction resulted in a 5.5% increase in the patient’s survival in their meta-analysis report .
In patients with clinically significant upper abdominal disease, splenectomy can be accepted as part of primary or secondary cytoreductive surgery . Although we did not conduct research on surgical methods in our study, we would like to state that in the last years, minimally invasive surgical techniques have been increasingly used in surgical and gynecological oncology practice. For selected patients, laparoscopic splenectomy can a feasible and safe approach in recurrent ovarian cancer patients with isolated spleen metastasis. Less blood loss bleeding, decreased morbidity, more rapid recovery and shorter interval to the initiation of adjuvant therapy can be listed as the advantages of this surgical method [11, 12].
In the study by Magtibay et al., splenic metastasis was detected in 46% of patients with ovarian cancer. In addition, they indicated the most common involvement of the spleen region as hilus (65%), capsule (52%), and parenchyma involvement (16%), respectively . In the study by Tanner et al. of ovarian, tubal, and peritoneal cancer patients, the most common spleen involvement site was indicated as capsule, hilum, and parenchyma, respectively . In addition, the most common spleen involvement site was reported as capsule in a study consisting of a similar patient group by Yasin et al. . In the study by Bacalbasa et al. which only included of patients with ovarian cancer, splenic involvement area was showed as capsule in the first frequency and parenchyma in the second frequency . In our study, parenchymal involvement of the spleen was not the most frequent occurrence, similar to the literature. When spleen involvement sites were evaluated, it was observed that hilus involvement was the most common when there was a single involvement site, and, if multiple involvement regions existed, the togetherness of hilus and capsule together was the most frequent.
Parenchymal involvement of the spleen is considered stage 4, according to the ovarian cancer FIGO staging system. However, Magtibay et al. reported that patients with disease that directly involved the splenic parenchyma did not appear to have a more unfavorable prognosis compared to patients with disease involving only the splenic hilum or capsule . They added that parenchymal splenic disease did not affect overall survival when compared to that of patients exhibiting only hilar or capsular disease involvement. On the other hand, Bacalbasa et al. reported that the presence of parenchymal splenic metastases is associated with significantly poorer survival when compared to hilar or peritoneal seeding in ovarian cancer . Tanner et al. reported similar results, and they reported that parenchymal splenic involvement is an independent risk factor for poor prognosis in patients with advanced ovarian, fallopian tube, and primary peritoneal cancer . Contrarily, Yasin et al. reported in their study that advanced ovarian, tubal, and peritoneal epithelial cancer patients with hilus involvement have a lower overall survival . In our study, there was no statistically significant difference between spleen involvement sites and overall survival. However, the worst survival in our study was found in those with only capsule involvement although this was not statistically significant.
The strengths of our study are high number of cases, the surgical and histopathological evaluation performed in a single tertiary cancer center by the same team and the long patient’s follow-up period.
There are many factors affecting prognosis in ovarian cancer such as tumor histology, stage, BRCA mutation, angiogenic phenotype. We could not evaluate the effects of each of these prognostic factors separately in overall survivals that we compared in our study. This is the important limitation of our study. It is not a routine practice to look at the BRCA mutation in patients with ovarian cancer in our country, and the use of PARP inhibitors is not yet approved in our country. Therefore, although the number of patients with BRCA mutation positive and using PARP inhibitors has increased in recent years, it is still limited. On the other hand, the retrospective design and low number of patients with only parenchymal metastases can be considered as the weaknesses of the study.
In the future, studies involving large numbers of patients are needed to examine the relationship of splenic involvement sites with survival and other prognostic factors in advanced ovarian, tubal and peritoneal epithelial cancer.
In conclusion, this study had the largest number of patients in the literature in an examination of the relationship between spleen involvement and overall survival. When the subgroups were evaluated in this study, although it was not statistically significant, the worst overall survival was found in the group with capsule involvement of the spleen.
While parenchymal involvement of the spleen is considered to be stage IV according to FIGO staging, failure to detect low overall survival in patients with parenchymal involvement in our study will provide a remarkable perspective on the relationship between parenchymal involvement and prognosis.