"has been an ongoing topic" is a correct and usable phrase in written English
It can be used to describe a topic or subject that has been discussed or focused on for a long period of time, with no clear end in sight. Example: Climate change has been an ongoing topic of debate and concern among scientists and policymakers for decades.
Due to their high toxicity, rapid and sensitive field detection of these compounds has been an ongoing topic of interest.
In addition, machines of this sort provide at least a simple model of how internal states whose effects on output occur by means of mechanical processes can be viewed as representations (though the question of what, exactly, they represent has been an ongoing topic of discussion (see sections 4.4 5).
The ability of the Nf1 gene product to act as a Ras GAP has been known for a quarter of a century (Ballester et al., 1990; Xu et al., 1990), but the degree to which this function accounts for some or all Nf1 phenotypes has been an ongoing topic of research with relevance for therapeutic strategies.
Optimal surgical management, and specifically – the indications for, and optimal extent of surgical staging have been an ongoing topic of controversy (Mariani et al, 2000; Benedetti Panici et al, 2008; Mariani et al, 2008; Bernardini et al, 2009; Neubauer et al, 2009; Dowdy et al, 2012).
It has been an ongoing issue.
The injury had been an ongoing issue.
Spatial audio coding (SAC) [5] has been an ongoing research topic in recent years for the high-efficient compression performance.
Nanotechnology has been an ongoing hot topic of discussion in public health as researchers claim that nanoparticles could present possible dangers in health and environment, Mnyusiwella et al. [2].
Visible-light-driven photocatalytic hydrogen production has been an ongoing hot topic for clean and renewable energy, for which I III VI multinary metal sulfides play an important role owning to their unique ability of bandgap manipulation by composition.
This has been an ongoing problem.
Renewable energy in the GCC has additionally been an ongoing topic of academic interest with many authors considering policies that could stimulate renewables adoption [3, 41, 49, 50, 51, 52, 53, 54] and further developing economic top-down and technological bottom-up models to simulate policy impacts [55, 56, 57, 58, 59].
