Clear Cell  carcinoma of the uterus is an uncommon type of endometrial cancer and is considered a high risk group (greater chance of relapse or recurrence than the more common type called adenocarcinoma.) Most authorities recommend additional therapy after surgery, though there is no consensus on what's best,  radiation (whole abdomen WART, or pelvis) and/or chemotherapy. We generally use postOp pelvic radiation someitmes combined with chemotherapy in non-protocol patients. (see the NNCN guidelines for clear cell cancer.) A recent literature review noted that these patients often relapse in the pelvis (unlike serous which often relapses in the abdomen) and postOp pelvic irradiation is useful.

 

Several reports in the literature have shown that, compared with endometrioid adenocarcinoma, patients with papillary serous (PS) and clear cell (CC) histologic features do worse. PS or CC cancers of the uterus are often associated with lymphatic invasion, deep myometrial invasion, intra-abdominal relapse, and a poor outcome. In the 2001 FIGO report, of 5914 patients, 305 had PS and 140 had CC cancer. The 5-year survival rate was 54.3% and 63.2% for PS and CC, respectively, compared with 79.9% for endometrioid carcinoma. When only patients with Stage I disease were analyzed, the 5-year survival rate was 72% for PS and 79.6% for CC, respectively. Even women with stage I serous cancer may benefit from postOp chemotherapy +/- radiation (go here).
 



Outcome and patterns of failure in pathologic stages I–IV clear-cell carcinoma of the endometrium: implications for adjuvant radiation therapy.
Kevin T. Murphy, International Journal of Radiation Oncology*Biology*Physics,2003; 55:5 : 1272-1276

Endometrial carcinoma is the fourth most common cancer in women, with an estimated 35,000 cases per year in the United States  Fortunately, most are classified as adenocarcinoma and have a favorable prognosis. However, approximately 5% of patients present with clear-cell carcinoma   These tumors are considered more aggressive with poorer outcomes.

Most investigators group clear-cell tumors together with the more common papillary serous histology Thus, many clear-cell patients are often treated with whole-abdominal radiation therapy (WART) and/or chemotherapy, even when the disease is confined to the uterus. Although selected studies have focused solely on clear-cell histology , most include a limited number of patients  or fail to describe in detail the adjuvant therapy administered  and sites of failure. As a result, the optimal management of these patients remains less defined.

The purpose of this study is to analyze the outcome and patterns of failure in pathologic Stages I–IV clear-cell carcinoma of the endometrium treated at our institution and to discuss implications for adjuvant radiation therapy (RT). Clear-cell carcinoma comprises a small percentage of endometrial cancers, frequently presents as a mixed histology, and has a poor overall outcome. Unlike papillary serous tumors, clear-cell carcinoma does not seem to have a high propensity for abdominal failure. Our results thus do not support the routine use of whole-abdominal RT in these patients. Future protocols should focus instead on combinations of locoregional RT and chemotherapy to reduce the risk of local and systemic recurrence.

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