Ovarian Tumors of Low Malignant Potential

Ovarian epithelial tumors of low malignant potential or borderline ovarian tumors account for approximately 15% of ovarian epithelial tumors.13 Borderline ovarian tumors with serous or mucinous histologies are the most commonly observed (65% and 32%, respectively). Patients with these lesions tend to be younger than those with invasive ovarian carcinoma (average age at diagnosis: 49 years), and a large portion of these tumors occurs in the 15- to 29-year-old age group.79

Surgery is required for diagnosis, and staging is approached in the same fashion as for invasive ovarian carcinoma. In review of the literature, Tinelli and colleagues80 showed 70% of cases presented as stage I and an additional 10% presented as stage II. Borderline tumors have an excellent prognosis with 5-year survival ranging between 85% and 97% and 10-year survival between 70% and 95% mainly owing to late recurrences13 (Fig. 7-26).

The more frequent occurrence of ovarian tumors of low malignant potential among women of reproductive age and the overall excellent prognosis have cast doubt on the need for aggressive surgical staging in these patients. Lin and colleagues81 compared traditional staging approaches with limited procedures in a cohort of 255 women diagnosed with serous borderline ovarian tumors. Forty-seven percent of patients were upstaged and women undergoing cystectomy alone were more likely to recur in either the ipsilateral or contralateral ovary. Morris and colleagues82 reviewed the outcomes of 43 patients at a single institution who were diagnosed with borderline ovarian tumors and had undergone conservative surgery. Patients undergoing ovarian cystectomy were more likely to require additional surgery (63% versus 40%) in the future and were more likely to have recurrences (75% versus 24%) compared with women undergoing oophorectomy. In one of the largest series reported in the literature, Zanetta and colleagues83 showed a recurrence rate of 19% in 189 cases treated conservatively versus 4.6% in 150 cases treated by hysterectomy and bilateral oophorectomy. Conservative surgery did not seem to impact survival, and all but one woman with recurrent disease were salvaged by further surgery. It seems reasonable to offer conservative surgery to women with borderline ovarian tumors desiring fertility preservation; however, they should be cautioned regarding the risk

Figure 7-26. Carcinoma of the ovary: patients treated in 19992001. Survival by histology, N = 5799. (From Heintz A, Odicino F, Maisonneuve P, et al: Carcinoma of the ovary. Int J Gynaecol Obstet 95(Suppl 1):S161-S92, 2006, Figure 8.)

Overall Survival (%) at

Patients

Mean Age

Hazard Ratio*

Histology

(N)

(yr)

1 Year

2 Years 3 Years 4 Years

5 Years

(95% CI)

Borderline 866 49.3 97.7 94.1 92.1 90.2 87.3 Reference

Malignant 4933 57.6 87.4 72.7 62.9 54.9 49.7 1.9 (1.5-2.3)

*Hazard ratios and 95% confidence intervals obtained from a Cox model adjusted for age, stage, and country.

Borderline 866 49.3 97.7 94.1 92.1 90.2 87.3 Reference

Malignant 4933 57.6 87.4 72.7 62.9 54.9 49.7 1.9 (1.5-2.3)

*Hazard ratios and 95% confidence intervals obtained from a Cox model adjusted for age, stage, and country.

of recurrence and the need for future surgery. The usefulness of lymph node sampling has also been called into question, Seidman and Kurman,84 in their meta-analysis of over 4000 patients with serous borderline ovarian tumors, identified only 63 patients with lymph node lesions with a survival rate of 98%.

The need for complete surgical staging is justified, however, in the event that final pathologic analysis finds invasive disease missed on frozen section. Medeiros and associates72 reported in their meta-analysis that the pooled sensitivity for borderline ovarian tumors was low at 66% due to the greater incidence of false-negative results, resulting in a post-test probability of borderline tumors that was only 51% compared with malignant tumors. Similarly, Geomini and associates85 showed in their review of the literature on the accuracy of frozen-section diagnosis that sensitivity varied between 65% and 97% and the specificity between 97% and 100%. Factors that lower the sensitivity of frozen-section diagnosis included large neoplasms, mucinous tumors, and tumors exhibiting extraovarian disease.

Advanced-stage mucinous borderline ovarian tumors have a graver prognosis, and a number of studies show that these tumors may represent metastases from appendiceal primaries, especially in the setting of pseudomyxoma peritoneii.86 An appendectomy should be considered if the appendix is present, and the frozen section suggests a mucinous histology. In the event of advanced-case disease, a total abdomi-

Table 7-4. Surgically Documented Complete Response Rates to Platinum-Based Chemotherapy According to Residual Disease in Patients with Advanced Serous Ovarian Tumors of Low Malignant Potential

Author

Complete Response

Macroscopic Disease Microscopic Disease

Kliman et al88 Nation and Krepart89 Chambers et al90 Hopkins and Morley91 Gershenson and Silva92 Sutton et al93 Barakat et al87 Total

0/1

0/2

2/2

0/1

1/1

1/3

2/4

2/5

2/8

4/6

2/7

From Barakat RR, Benjamin I, Lewis JL Jr, et al: Platinum-based chemotherapy for advanced-stage serous ovarian carcinoma of low malignant potential. Gynecol Oncol 59:390-393, 1995.

nal hysterectomy, bilateral salpingo-oophorectomy, and maximal cytoreduction are advised. Barakat and associates87 showed a higher rate of complete clinical response following platinum based chemotherapy among patients with advanced-stage borderline ovarian tumors who were left with microscopic residual disease (Table 7-4). Gershenson and colleagues94 confirmed the latter results when they demonstrated that macroscopic residual disease was an independent adverse prognostic factor. Although recurrences are uncommon, 10% to 20% of patients are expected to have recurrences, with malignant transformation in 2% to 7% of cases.95 As in epithelial ovarian cancer, Crispens and associates96 demonstrated that for patients who underwent complete or optimal resection their recurrence had a better response to chemotherapy and better overall survival (92% versus 35%).

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