Reassessing rare cancers
Ovarian cancer shows how genetic subtyping allows similarities between cancers to guide treatment trials
Rare cancers are defined as those with an incidence of less than 6 cases per 100 000 population per annum. For uncommon cancers, the incidence ranges from 6 to 12 per 100 000 population per annum.1 Typically, the survival for rare cancers is not as good as with more common cancers.2 In an audit published by Cancer Australia in 2014, over 80% of cancer research funding went to the haematological cancers and only five solid cancers (breast, colorectal, prostate, melanoma and lung cancers), yet rare cancers account for 30% of cancer deaths.3 Also, if less research is being performed to provide data, and the low incidence of rare cancers makes large randomised clinical trials impractical, there are few evidence-based guidelines regarding rarer cancers to which clinicians can refer.
Solutions to these issues will not only have an impact on the management of rare cancers. Increasingly, common cancers are being divided into smaller and smaller subgroups according to their genetic make-up. The pattern of mutated genes is important for determining the genetic targets that may respond to the emerging targeted anticancer drugs or immunotherapies.
Ovarian cancer is a good example of an uncommon cancer, with an incidence…