Chemotherapy for adult women diagnosed with a rare type of ovarian cancer of all stages (malignant germ cell cancer of the ovary)

Malignant germ cell cancer of the ovary (type of ovarian cancer) is a very rare type of cancer. Malignant ovarian germ cell cancer is a term used to describe a group of heterogeneous rare tumours affecting the ovaries. These tumours start in the egg (ovum) producing cells of the ovary, whereas the more common epithelial ovarian cancers start in the cells that cover the surface of the ovary. Unlike epithelial ovarian cancers, these tumours are often diagnosed early and a combination of surgery and chemotherapy usually results in favourable long term overall survival. Due to its rarity, this review is based on only one very small RCT and one small retrospective study. The data from these studies were too sparse to adequately assess the effectiveness and safety of chemotherapy after surgery (adjuvant chemotherapy) in the treatment of malignant germ cell ovarian cancer. All comparisons were restricted to single study analyses and this review was only based on 32 women, so it was not adequately powered to detect differences in survival. Adverse effects of treatment and recurrence-free survival were incompletely documented and QoL was not reported in any of the studies. We did not find any studies that reported specifically on adults as this disease usually afflicts younger people as opposed to the older population, so there were problems in separating data on adults and children in many of the studies. Many of the treatments used were taken from experiences of treating patients with testicular cancer, as they look similar under the microscope and behave similar clinically. Due to the small number of patients with malignant germ cell cancer in the two studies, our review shows that there were no good quality studies assessing the role of chemotherapy in this disease, be it in early or late stages. There was insufficient evidence to conclude that any form of chemotherapy or best supportive care is superior over the other. This review highlights the need for future good quality, well designed studies.

Authors' conclusions: 

We found only low quality evidence on the use of chemotherapy in malignant germ cell tumours of the ovaries. Therefore we are unable to reach definite conclusions about the relative benefits and harms of chemotherapy use in this disease regardless of disease stage. Due to the benefit of chemotherapy in germ cell cancer of the testis, a trial of chemotherapy versus best supportive care is unlikely to be feasible. Despite this, good quality randomised studies are warranted in this disease to define the role of chemotherapy (type of chemotherapy, duration of treatment, benefit, short and long term toxicities). Given the rarity of this disease, we feel a trans-global approach would be essential in order to perform such trials.

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Background: 

Malignant germ cell tumour of the ovary occurs in up to 0.07% of woman globally. Due to its rarity, evidence for treatment is lacking and often extrapolates clinical trial results of testicular germ cell cancers. The investigation on this rare tumour is further compounded by the fact that its occurrence in the adult population is even less compared to their paediatric counterpart. At present, the effectiveness of chemotherapy, regardless of stage in malignant germ cell tumour of the ovary is not entirely clear.

Objectives: 

To evaluate the effectiveness and safety of chemotherapy in adult women with early stage, advanced and recurrent malignant germ cell ovarian cancers.

Search strategy: 

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), Issue 1, 2010, Cochrane Gynaecological Cancer Group Trials Register, MEDLINE and EMBASE up to April 2010. We also searched registers of clinical trials, abstracts of scientific meetings and reference lists of included studies.

Selection criteria: 

We searched for randomised controlled trials (RCTs), quasi-RCTs and non-randomised studies that compared systemic therapy in adult women diagnosed with germ cell ovarian cancer who have confirmed pathological diagnoses.

Data collection and analysis: 

Two review authors independently assessed whether potentially relevant studies met the inclusion criteria, abstracted data and assessed risk of bias.

Main results: 

We found one RCT and one retrospective study that met our inclusion criteria. The data from these studies were too sparse to adequately assess the effectiveness and safety of adjuvant chemotherapy in the treatment of malignant germ cell ovarian cancer. All comparisons were restricted to single study analyses and this review was only based on 32 women, so it was not adequately powered to detect differences in survival. Adverse effects of treatment and recurrence-free survival were incompletely documented and QoL was not reported in any of the studies. We did not find any studies that reported specifically on adults so there were problems in separating data on adults and children in many of the potentially relevant studies.

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