Ovarian serous tumors of low malignant potential (borderline tumors): outcome-based study of 276 patients with long-term (> or =5-year) follow-up

Long-term outcomes following conservative surgery for borderline tumor of the ovary: a large population-based study

OBJECTIVES

To examine outcomes in women treated with conservative surgery for borderline ovarian tumor in a large population-based cohort with long-term follow-up.

METHODS

Women treated by conservative surgery for borderline tumor of the ovary from 1982-2004 within a large HMO setting were identified using electronic and tumor registry data. Chart review was performed when electronic data were incomplete. The indications for and outcomes from any subsequent gynecologic surgery and the risk of recurrent ovarian borderline and malignant tumor were determined. Risk factors for recurrence were analyzed using multivariate regression.

RESULTS

Among one hundred and ninety-three patients identified, the average age was 33 (12-95), with 97% having apparent Stage I disease. Patients were followed with remaining ovarian tissue in situ for a mean of 6.9 years, with 59 women having 10 or more years of such observation. There were 21 recurrences with borderline tumor (11%) with a median time to first recurrence of 4.7 years; women treated by cystectomy recurred three times more often compared to women treated by oophorectomy (23% versus 7%). Two patients (1%) recurred with malignant disease involving remaining ovarian tissue, both within the first 3 years after surgery, with one death due to recurrence. During long-term follow-up, 19% of patients eventually underwent complete removal of ovarian tissue: in 8%, the surgery was prophylactic, in 5%, surgery was done for benign pathology, and in 6% for recurrent disease.

CONCLUSIONS

In this population-based HMO setting, 11% of women treated with conservative surgery for borderline tumor recurred; however, half of these recurrences were successfully managed by repeat conservative surgery, with only 6% of women overall needing eventual complete removal of ovaries for recurrent disease. Patients treated by cystectomy were three times more likely to recur than those treated by oophorectomy. Malignant recurrences were rare, and while borderline recurrences often occurred more than 3 years after initial surgery, late malignant recurrences were not observed. These favorable long-term outcomes provide support for conservative surgery for these women.

Lymph node involvement in ovarian serous tumors of low malignant potential (borderline tumors): pathology, prognosis, and proposed classification

The occurrence of regional lymph node involvement (LNI) in patients with primary ovarian serous tumors of low malignant potential (S-LMP), although well described in the literature, continues to be problematic. Most studies indicate that LNI is not associated with an adverse prognosis, but there has not been a comprehensive study addressing the histologic patterns of LNI, the importance, if any, of classifying the type of LNI (ie, as either noninvasive or invasive in analogy to peritoneal implant classification), or the presence and significance of associated endosalpingiosis. To further evaluate LNI in S-LMP, 74 patients with ovarian S-LMP and a lymph node biopsy or sampling were studied. Thirty-one of 74 patients had LNI in pelvic (18; 58%), mesenteric/omental (9; 29%), paraaortic (8; 26%), or supradiaphragmatic (2; 6%) lymph nodes. The number of involved nodes ranged from 1 to 20 (mean, 11.1). Four patterns of LNI were identified: individual cells, clusters of cells, and simple, nonbranching papillae (28 of 31; 90%); intraglandular (21 of 31; 68%); cells with prominent cytoplasmic eosinophilia ("eosinophilic cell" pattern) (16 of 31; 52%); and micropapillary pattern (5 of 31; 16%). LNI was diffuse in at least one lymph node in 13 patients (42%) and formed nodular aggregates greater than 1 mm in 6 patients (19%). Nodal endosalpingiosis was present in 58% of cases with LNI compared with 35% without LNI (P=0.06). There was no significant difference in survival for patients with LNI compared with patients without LNI. However, the presence of discrete nodular aggregates of epithelium greater than 1 mm in linear dimension without intervening lymphoid tissue was associated with a statistically significant decreased disease-free survival when compared with other patterns of LNI (P=0.02). Nodular aggregates were strongly associated with desmoplastic fibrous stromal reaction (P=0.001) and micropapillary architecture (0.02). There was also a trend for decreased survival among patients with LNI without associated endosalpingiosis (56%) compared with patients with LNI associated with endosalpingiosis (85%) and those with endosalpingiosis only (93%). This study suggests that patients with ovarian S-LMP may be further substratified into risk categories by the presence of nodular aggregates of S-LMP in lymph nodes, a feature that is more common in cases with micropapillary architecture and associated stromal reaction in the intranodal tumor. This high risk pattern of LNI may have a predictive value similar to invasive peritoneal implants and deserves independent evaluation in future studies of S-LMP.

Retrospective cohort study of surgical staging for ovarian low malignant potential tumors

OBJECTIVE

The purpose of this study was to determine the benefit of surgically staging ovarian low malignant potential tumors.

STUDY DESIGN

This was a retrospective cohort study of all ovarian low malignant potential tumors that were diagnosed by frozen section or final pathologic review from 2003 to 2005.

RESULTS

Twenty-two of 32 patients (69%) were staged surgically. Sixteen low malignant potential tumors were stage I by final pathologic review, and 4 tumors were upstaged to stage II-III disease. Two other patients had early invasive ovarian carcinoma, despite a frozen section that suggested low malignant potential; 1 patient received adjuvant chemotherapy. The tumors of 10 women (31%) were unstaged. Frozen section suspicion of low malignant potential (P = .003) and surgery by a gynecologic oncologist (P < .001) correlated with staging. Preoperative CA-125, intraoperative blood loss, and postoperative hospitalization were increased in patients with staged disease (each P < .05). Two women who underwent fertility-sparing surgery experienced a recurrence in the contralateral ovary.

CONCLUSION

Surgical staging of ovarian low malignant potential tumors has limited value for most patients, unless invasive carcinoma is diagnosed by final pathologic review.

Gene Expression Profiling of Ovarian Tissues for Determination of Molecular Pathways Reflective of Tumorigenesis

Ovarian cancer is the fourth leading cause of gynecological cancer death among women in the United States. Early detection is a critical prerequisite to initiating effective cancer therapy. Gene microarray technology and proteomics have provided much of the biomarkers with potential use for diagnosis. However, more research is needed to fully understand disease onset and progression. To this end, we have performed microarray analysis with the goal of identifying molecular interaction networks defining tumor growth. Microarray analysis was performed on a limited set of ovarian tissues with various pathological diagnoses using Human Genome Focus Array (HGFA) for the detection of approximately 8500 human transcripts. Hierarchical clustering identified groups of ovarian tissues reflective of low malignant potential/early cancer onset and possible pre-cancerous stages involving small molecule, cytokine and/or hormone-dependent feed-back responses specific to the pelvic reproductive system and a priori initiated tumor suppression mechanisms. ANOVA followed by post hoc Scheffe confirmed our hypotheses. Moreover, we established a protein/protein interaction database associated with HGFA probe sets. This database was used to build and visualize molecular networks integrating small but significant changes in gene expression. In conclusion, we were able for the first time to delineate an intersecting genetic pattern linking ovarian tissues reflective of low potential malignancy/early cancer onset stages via long distance signaling between tissues of gynecological origin.

Autoimplants in Serous Borderline Tumors of the Ovary

The clinical and pathologic features of serous borderline tumors (SBTs) with autoimplants (AIs) were studied with emphasis on their relation to survival, ovarian SBT with a micropapillary pattern, and their distinction from serous adenocarcinoma. The 30 patients ranged in age from 17 to 70 years (mean, 35.8 years). Two had stage I disease, 10 had stage II disease, and 18 had stage III disease. Twenty-five patients had bilateral ovarian tumors. In 28 cases, AIs were present on the surface of the neoplasm or between exophytic surface tumor papillae; in 2 cases, AIs were between papillae within intracystic tumor. The AIs consisted of single cells or glands and clusters of cells with mild to moderate nuclear atypia within a fibroblastic stroma; the stroma dominated over the epithelium in extent within the AI. In many cases, the epithelial cells in the AI had abundant eosinophilic cytoplasm. All but 2 of the patients had coexisting noninvasive peritoneal implants; 3 of them also had invasive peritoneal implants. Six of the SBTs had a micropapillary pattern; 3 of these were stage III and 3 stage II tumors. Clinical follow-up was available for 11 patients. Eight were alive and well after 4 to 7 years (mean, 5 years); 3 of these patients had stage II disease and 5 had stage III disease. Three were dead of disease after 7 to 12 years (mean, 9 years). Two patients who died of disease had stage III disease, and 1 of them had invasive implants. The third patient had stage II disease, invasive implants, and the tumor was of the micropapillary type. Our study indicates that the majority of patients with SBT with AI have stage II or III disease and abundant exophytic tumor. SBTs with AI had a micropapillary pattern in 20% of the cases. AIs do not appear to have an adverse impact on survival when controlled for peritoneal implant type and for this reason must be distinguished from true stromal invasion in serous carcinoma, a misdiagnosis sometimes made, or seriously entertained, initially in these cases. Features that favor AI over carcinoma arising in an SBT are 1) a location between tumor papillae or on the ovarian surface 2) a predominance of stroma over epithelial cells, and 3) the "borderline" cytologic appearance of epithelial cells.

Ovarian Atypical Proliferative (Borderline) Mucinous Tumors: Gastrointestinal and Seromucinous (Endocervical-Like) Types are Immunophenotypically Distinctive

Ovarian atypical proliferative (borderline) mucinous tumors of gastrointestinal and seromucinous types are considered subtypes within the mucinous tumor category despite the presence of distinctive clinicopathologic features that seromucinous tumors share with pure serous tumors. Immunophenotypic differences have not been extensively investigated. Immunohistochemical studies were performed to compare the expression patterns of cytokeratins 7 and 20 (CK7, CK 20), estrogen and progesterone receptors (ER, PR), CA-125, mesothelin, and WT-1 in 28 tumors of gastrointestinal type and 12 tumors of seromucinous type. Both gastrointestinal and seromucinous type tumors had a high frequency of CK7 expression (93% and 100%, respectively). The gastrointestinal type tumors were characterized by frequent expression of CK20 (86%) and CDX2 (39%), infrequent expression of CA-125 (11%) and mesothelin (7%), and lack of expression of ER, PR, and WT-1. In contrast, the seromucinous type tumors were characterized by frequent expression of ER (100%), PR (67%), CA-125 (92%), and mesothelin (83%), infrequent expression of WT-1 (8%), and lack of expression of CK20 and CDX2. The gastrointestinal and seromucinous types of atypical proliferative mucinous tumors are immunophenotypically distinctive tumors. The former are characterized by expression of markers of gastrointestinal-type differentiation (CK20 and CDX2), whereas the latter are characterized by expression of "müllerian-type" markers (ER, PR, CA-125, and mesothelin). Expression of the latter markers in the seromucinous tumors, which also are expressed in pure serous tumors, and lack of expression of gastrointestinal-type markers, combined with the clinicopathologic features these tumors share with pure serous tumors, support the concept that this subtype is more closely related to serous than gastrointestinal type mucinous tumors and justify the designation "seromucinous."

Distinction between serous tumors of low malignant potential and serous carcinomas based on global mRNA expression profiling

OBJECTIVES

The molecular pathogenesis of ovarian serous tumors of low malignant potential (S-LMP) is not well understood, although the collective data suggest that they arise through molecular mechanisms distinct from those leading to conventional serous carcinomas (S-Ca). To further examine the molecular differences between these two diseases, we studied the gene expression pattern of ovarian S-LMP and S-Ca using high-density spotted cDNA and tissue microarrays.

METHODS

Total RNA from 23 ovarian S-LMP and S-Ca was analyzed on 43,200 spot cDNA microarrays and the differential expression of proteins encoded by differentially expressed genes was validated using tissue microarrays.

RESULTS

Unsupervised hierarchical clustering analysis of filtered data showed a complete separation between S-LMP and S-Ca, based predominantly on a small set of genes expressed at higher levels in S-LMP than in S-Ca. Many genes previously identified as up-regulated in ovarian carcinoma relative to normal ovarian tissue were expressed at even higher levels in S-LMP. These genes included mucin-1, mesothelin, HE4, PAX 8, and apolipoprotein J/clusterin. Immunohistochemical staining of tissue microarrays confirmed higher expression of selected proteins encoded by these genes in the S-LMP. Few genes were expressed at a higher level in S-Ca; these included E2F1, topoisomerase IIalpha, and cyclin E, with higher levels of cyclin E protein confirmed by immunohistochemistry.

CONCLUSIONS

S-LMP and S-Ca are distinguished at the molecular level by a relatively small gene set, suggesting the pathogenesis of S-LMP as well as S-Ca may involve molecular pathways that escape detection by global gene expression profiling. In order to obtain biologically and clinically relevant information about the mechanisms involved in ovarian carcinogenesis, future studies based on molecular profiles of ovarian cancer should include analyses of low malignant potential tumors. Inclusion of such tumors is also critical to the evaluation of the efficacy of potential new diagnostic and/or therapeutic biomarkers.