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1522 GCIG Rare Tumor Consensus Review & Guidelines
based combination therapy is commonly used. Given
the poor response to standard therapy, it is vital that
the biology of these tumours is investigated to identify
novel targets. It is unlikely that a randomised trial would
be feasible given the rarity however the development of
international tumour registries might help to clarify the
optimum management and eliminate the inherent bias of
case reports.
Borderline Ovarian Tumors
(Harter et al., 2014)
Since the early 1970s, the World Health Organization
and the International Federation of Gynecology and
Obstetrics have classified borderline ovarian tumors as
an independent group of ovarian epithelial tumors. When
the diagnosis of BOT is made or suspected, gynaecologic
oncologists are confronted with the question of choosing
conservative or radical surgery. Radical surgery with
complete staging includes median laparotomy, complete
inspection and palpation of the abdominal cavity, cytology,
resection of all suspicious tissue, bilateral salpingo-
oophorectomy, total hysterectomy, omentectomy,
and multiple peritoneal biopsies. However, the role of
hysterectomy is not clearly demonstrated. At least for
early BOT the staging surgery via laparoscopy seems to
be a safe alternative. Although even the most current
FIGO recommendations include lymphadenectomy as
part of complete staging in BOT, there is no rationale
for systematic lymphadenectomy and this procedure is
routinely not indicated. Available data suggests that in
general the rate of recurrence is higher after conservative
management. This has to be individually discussed with
the patient keeping in mind that BOT is often diagnosed
before completion of family planning. To date, there are
no data supporting any benefit from adjuvant therapy
(chemotherapy or radiotherapy), even in advanced stage
disease. BOT with invasive implants are according to the
recent WHO classification classified as low grade tumors.
The optimal systemic therapy for this small subgroup of
patients remains unclear. In case, of relapse, as in primary common ovarian subtypes. The benefit of oxaliplatin and
BOT, surgery with the aim of complete cytoreduction
remains the cornerstone for the treatment of recurrence.
Low Grade Serous Ovarian Cancer
(Gourley et al., 2014)
Low grade serous ovarian cancer (LGSOC) is a recently
described histological subtype of ovarian cancer which
is clinically and molecularly distinct from the four other
main histological subtypes (high grade serous, clear
cell, endometrioid and mucinous). It is characterised by
mutations in K-RAS, N-RAS and BRAF. In particular,
it differs from high grade serous ovarian cancer
(HGSOC) in that it presents at a much younger age, is
more indolent and is relatively chemo-resistant. It may
arise de novo or following a previous diagnosis of serous
borderline tumour. Optimal management involves
maximal debulking surgery. In view of its relative
chemoresistance, neoadjuvant chemotherapy is not
recommended and the role of post-operative or adjuvant
chemotherapy is uncertain. Retrospective analyses in the
relapsed disease setting suggest that endocrine agents
such as tamoxifen and letrozole have a higher response
rate than chemotherapy and are a useful therapeutic
option. MEK inhibition has shown promise in one
prospective single arm phase II study. In addition small
retrospective series suggest that bevacizumab may have
a significant role in management. Historically, very few
clinical trials have been performed exclusively in this
tumour type and as such specific data guiding optimal
management is limited. There are however a number
of new international collaborative trials, some of which
have strong translational components, which should help
inform the future management of this disease.
Ovarian Mucinous Carcinomas
(Ledermann et al., 2014)
Mucinous carcinomas of the ovary can be primary or
metastatic in origin. Specialised pathological review
and immunophenotyping have increased the ability
to distinguish between primary ovarian mucinous
tumours and those with a metastatic origin. Not only are
primary mucinous carcinomas rare, but the incidence
of this subtype of ovarian cancer is less common than
previously estimated. Most tumors are diagnosed at
an early stage, and the prognosis after surgery is good.
Advanced or recurrent mucinous carcinoma of the ovary
responds poorly to current cytotoxic treatments, and
the prognosis is poor. The guidelines for surgery are
established but those for chemotherapy are less clear.
The is no evidence that adjuvant chemotherapy for
early stage disease is beneficial. Platinum and paclitaxel
are commonly used for advanced or recurrent disease
but the tumour response rate is lower than in the more
fluoropyrimdines is uncertain as it has been difficult to
conduct clinical trials. The use of drugs active in gastro-
intestinal tumours is a reasonable option, particularly as
many of these tumours are probably of gastro-intestinal
origin. Research to identify inhibitors of the factors
driving the tumour growth pathways is needed.
Ovarian Clear Cell Carcinoma
(Okamoto et al., 2014)
Clear cell carcinoma of the ovary (OCCC) is a histologic
subtype of epithelial ovarian cancer with a distinct clinical
behavior. There are marked geographic differences in
the prevalence of CCC. The OCCC is more likely to be
detected at an early stage than highgrade serous cancers,