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the ovary is a common site of metastases from other primary malignancies , and 5 - 30% of ovarian cancers are metastatic malignancies .
the most common primary origins are the breast , colon , and stomach ( 1 ) .
the incidence rate of metastatic ovarian cancer appears to be somewhat higher in asia compared to western countries ( 2 - 7 ) .
the prevalence of metastatic ovarian tumors appears to be associated with the incidence rates and spread patterns of primary malignancies . when gynecologists are confronted with tumors metastasized to the ovaries , the pre- and intraoperative distinction of the tumors from primary ovarian malignancies is often difficult .
a history of malignancy can provide a useful clue for diagnosing metastatic ovarian tumor , but symptoms due to the tumor can mask the primary neoplasm . occasionally , metastatic ovarian tumors mimic a primary ovarian neoplasm morphologically and clinically .
furthermore , the radiological features of metastatic ovarian cancer show considerable variability ( 8 - 11 ) . because metastatic ovarian cancer is not a target of typical chemo- and radiotherapy , there are few clinical reports on tumor management or prognostic factors .
cytoreductive surgery in metastatic ovarian cancer may be beneficial for the initial diagnosis or symptom relief , but the survival benefit of surgery remains controversial ( 3 , 5 , 12 - 16 ) . in the present study , we evaluated the prevalence of metastatic ovarian cancer and preoperative characteristics , including diagnostic imaging findings , origin of primary malignancy , age of patient , mass size , bilaterality , and serum markers .
we identified patients from the records of the department of pathology at the catholic university of korea , retrieved through searches of the pathology report database and the medical informatics cancer registry at the catholic medical center .
the records of 821 patients with ovarian malignancies between 1 january 1996 and 31 december 2006 were screened , according to international classification of disease ( icd)-10 codes . for inclusion in this study ,
ovarian metastasis confirmed by histological and immunologic stains ( i.e. , cytokeratins 7 or 20 ) and pathological or clinical confirmation of the primary tumor were required .
we included data from patients with metastatic tumor from other genital tract ( i.e. , uterus , cervix and fallopian tube , only except ovary ) .
two cases of primary ovarian cancer and one case with uncertain information were excluded based on the advice of a participating pathologist ( a.w.l . ) .
we recorded patient information , including age , menopause status , origin of the primary malignancy , the sequence and interval of diagnosing the primary and secondary tumors , cell type , radiology findings , preoperative serum cancer antigen ( ca)-125 concentration , ascites , mass size , bilaterality , cytoreductive surgery results , and survival .
not all clinical data were available for all cases . therefore , we calculated percentages based on the number of cases for which appropriate data were available .
surgical treatment was categorized as ( 1 ) extensive ( e.g. , optimal mass removal by primary tumor resection plus total hysterectomy with unilateral or bilateral salpingo - oophorectomy and/or pelvic lymphadenectomy , omentectomy , or other excisional mass removal procedures ) or ( 2 ) minimal ( e.g. , palliative debulking , including incomplete removal of primary tumor and salpingo - oophorectomy , wedge resection or biopsy of ovarian masses ) .
surgery was defined as optimal when the largest residual tumor mass was < 2 cm .
statistical analyses included anova , fisher 's exact test , wilcoxon rank sum test and kruskal - wallis test as appropriate .
we computed survival curves using the kaplan - meier 's method , and we analyzed the prognostic variables with the log - rank test ( univariate ) and the cox proportional hazards model ( multivariate ) .
the study was approved by the appropriate institutional review board at the catholic medical center .
metastatic ovarian malignancy accounted for 112 ( 13.6% ) of the 821 ovarian malignancies . more than 70% of those were metastases from the gastrointestinal tract .
the mean age of patients was 46.811.0 yr , and 39 ( 34.8% ) of them were postmenopausal .
primary malignancies were detected first in 48 ( 42.9% ) patients and simultaneously with ovarian metastases in 61 ( 54.5% ) patients .
adjuvant therapy ( postoperative chemotherapyradiotherapy ) was done in most of patients ( 98.2% ) .
the number of patients with metastatic ovarian cancers that did not originate in the gastrointestinal or gynecologic organs was relatively small , and further classification of data was required for effective statistical analyses .
therefore , we re - categorized the data into four subgroups , according to primary origin : 1 ) colorectal cancer , 2 ) stomach cancer , 3 ) gynecologic cancer , and 4 ) others sites , including gallbladder , pancreas , breast , lung , lymphoma , and unknown origin .
eighty - four ( 75% ) cases were preoperatively diagnosed by ultrasonography , computed tomography , or magnetic resonance imaging .
the mean size of the largest masses was 9.75.5 cm , and 54.5% of the cases had bilateral ovarian involvement .
there were no statistically significant differences in the largest mass size or bilateral ovarian involvement among the subgroups .
we considered preoperative mass detection by imaging successful if provided any suspicion or suggestion of the ovarian metastasis or malignant mass .
accordingly , the preoperative detection rate with imaging was 75% , and it appeared to be higher for ovarian metastases from colorectal and gynecologic origins ( p=0.050 ) .
multilocularity was a typical pattern in ovarian metastases from colorectal or gynecologic origins ( p=0.028 ) .
a large number of metastatic ovarian cancers showed multilocular and mixed ( cystic - solid ) patterns with or without ascites , suggesting primary ovarian cancer .
thirty - two ( 40.0% ) of those had elevated serum ca-125 concentrations ( 35 u / ml ) , and the mean values of preoperative serum ca-125 , according to the primary tumor site , were not significantly different among the subgroups ( p=0.322 ) ( table 3 ) .
the survival rate of subgroup 3 ( gynecologic origin ) was significantly better than that of other subgroups ( p=0.002 ) , and there were no significant differences in survival among subgroups 1 , 2 , and 4 .
although we initially attempted curative and optimal cytoreduction for all patients , optimal resection was achieved by extensive surgery in 62 ( 55.4% ) .
the median patient survival was 17 months after extensive cytoreduction and 9 months after minimal surgery .
2 , extensive surgery improved the survival outcome of metastatic ovarian cancer ( p=0.041 ) .
we analyzed prognostic variables and estimated hazard ratios for patient death with a log - rank test and cox proportional hazards model ( table 4 ) .
metastasis from non - gynecologic malignancies and minimal resection were unfavorable prognostic factors in a univariate analysis .
ovarian metastasis from gynecologic origin was a significant favorable prognostic factor in multivariate analysis ( p=0.004 ) .
in the present study , metastatic ovarian cancer accounted for 13.6% of all ovarian malignancies .
the overall incidence of metastatic ovarian cancer in the korean population is higher than that in europe and north america .
colorectal and stomach cancer were major primary origins , and the proportion of breast cancer origin was much lower in the present study compared to data from western countries ( 3 - 7 ) .
the global incidence of stomach cancer is concentrated in eastern asia and some south american , southeastern european , and african countries .
regionally , stomach cancer is the most common cancer in eastern asia and the third most common cancer in south america and southeastern europe .
breast cancer is the second most common and colorectal cancer is the third most common cancer worldwide after lung and breast .
the incidence rates of breast and colorectal cancer are highest in developed western countries and lowest in africa and asia
. however , japan and korea are exceptions , having age - standardized rates similar to europe ( 20 ) . according to the 2005 korean cancer registry , stomach , breast , and colorectal cancer , in that order , were the most common cancers in korean women .
the prevalence of metastatic ovarian cancer seems to reflect the overall incidence and ethnic variances of primary cancer . in the present study ,
the mean age of patients with metastatic ovarian cancer was approximately 10 yr lower than that of patients with primary ovarian cancer ( 17 ) .
. a known history of a primary malignancy is useful for diagnosis , but many cases present symptoms related to an ovarian mass without a history of malignancy . in this study ,
more than half of the metastatic ovarian cancers were diagnosed simultaneously with primary malignancies , and the proportion of bilateral ovarian involvement was 54.5% .
there were no significant differences in bilaterality and the largest mass size of metastatic ovarian malignancies based on the primary tumor site .
as described in previous radiology studies , the nature of an ovarian mass and lesion size may be useful for diagnosis ( 8 , 10 ) . in the present study ,
multilocularity was a more frequent pattern in metastatic ovarian tumors from colorectal or gynecologic malignancies .
however , differential diagnosis of ovarian masses based solely on radiology carries the risk of misinterpretation and may have adverse consequences for patients .
as shown in table 3 , serum concentration of ca-125 was not useful for detection .
in addition to morphological and clinical information , further evaluation , such as immunostains for cytokeratins 7 and 20 and other histopathological markers may be useful for differential diagnosis of metastatic ovarian cancers ( 2 , 18 , 19 ) .
the multivariate analysis to evaluate prognostic factors for metastatic ovarian cancer showed that the primary tumor site was the most important factor .
ovarian metastases of gynecologic origin had a much better prognosis than those from non - gynecologic organs . compared with metastases from non - gynecologic malignancy , carcinomatosis of advanced gynecologic cancer
is relatively confined to the intraabdominal cavity without distant metastasis and shows superficial spreading patterns ( 21 , 22 ) . from these reasons ,
the metastatic ovarian cancer from gynecologic malignancy might show longer survival than those from non - gynecologic organs .
metastatic cancer of colorectal origin showed favorable prognosis among other non - gynecologic cancers , but there was no significant prognostic difference in non - gynecologic metastatic cancers based on the primary tumor site .
as described in previous studies , surgical resection should be considered as indicated by a patient 's condition ( 5 , 12 - 15 ) .
second , information regarding diagnosis and treatment outcome was limited due to the study 's retrospective design .
however , it is difficult to execute a well - designed , prospective trial on this topic . continued follow - up and large - scale data collection will provide accurate , long - term information about metastatic ovarian cancer and the benefits of a secondary tumor screening program .
in addition to studies that evaluate outcomes of surgical resection , studies of chemotherapy outcomes are necessary . in conclusion , the incidence of metastatic ovarian cancer appears to be higher in korean women compared to the incidence in western countries .
the differential diagnosis of metastatic ovarian cancer is problematic , and multiple diagnostic approaches are required to enhance detection accuracy .
surgical intervention may be appropriate in some cases , and the extent and type of surgery should be decided on a case - to - case basis .
approximately 5 - 30% of the ovarian cancers are metastatic malignancies . 
 the prevalence of metastatic ovarian tumors varies with the incidence rates and spread patterns of primary malignancies . 
 we evaluated the prevalence , pre- and postoperative characteristics of metastatic ovarian cancer in korean women . 
 we reviewed the records for 821 ovarian malignancies with pathological consultation from 1996 - 2006 and recorded patient demographical , radiological , histopathological , and survival data . 
 the study included 112 cases of histologically confirmed metastatic ovarian cancer . 
 metastatic ovarian cancer accounted for 13.6% of all ovarian malignancy , primarily arising from the gastrointestinal tract . 
 the preoperative detection rate with imaging was 75% , and none of the radiological or serological features were useful for differential diagnosis . in multivariate analysis for prognostic variables , 
 the only significant factor was the primary tumor site ( p=0.004 ) . 
 furthermore , extensive resection increased survival for some patients . 
 the differential diagnosis of metastatic ovarian cancer can be problematic , so multiple diagnostic approaches are necessary . 
 the extent of cytoreductive surgery for this type of tumor must be decided on a case - by - case basis .