This study has received next to no media coverage. With RFR impacting so many people it makes me wonder, is this study valid?
Well first of all, lets be clear: that is not a study. Its a review article, basically a paper that summarizes a series of studies published. The review itself isn't valid or invalid necessarily, it simply takes a series of papers (which may or may not be correct or relevant) and then summarizes them.
As for validity, that is a summary of a lot of obscure papers on mechanisms by which RF fields could interact with cells, rats or in a few cases plants. Its hard to say if the conclusions are valid, but selecting a few papers at random, they are mostly very obscure journals and many report very specialized measurements that are far removed from demonstrating carcinogenic effects in humans. Its difficult to draw conclusions that are relevant to human health from that, although it does seem plausible that low frequency fields could have a measureable effect on cells or even rats.
Are low-intensity radio-waves carcinogenic?
Assuming you mean in people, that is a hard question to answer, and not the right question given a review article that does not address effects in people. A better place to look may be this review article:
Carcinogenicity of radiofrequency electromagnetic fields
published in The Lancet and addressing evidence of carcinogenicity in humans. To summarize:
The Working Group concluded that there is “limited evidence in humans” for the carcinogenicity of RF-EMF, based on positive associations between glioma and acoustic neuroma and exposure to RF-EMF from wireless phones. A few members of the Working Group considered the current evidence in humans “inadequate”. In their opinion there was inconsistency between the two case-control studies and a lack of an exposure-response relationship in the INTERPHONE study results; no increase in rates of glioma or acoustic neuroma was seen in the Danish cohort study,4 and up to now, reported time trends in incidence rates of glioma have not shown a parallel to temporal trends in mobile phone use.
The Working Group reviewed more than 40 studies that assessed the carcinogenicity of RF-EMF in rodents, including seven 2-year cancer bioassays. Exposures included 2450 MHz RF-EMF and various RF-EMF that simulated emissions from mobile phones. None of the chronic bioassays showed an increased incidence of any tumour type in tissues or organs of animals exposed to RF-EMF for 2 years. An increased total number of malignant tumours was found in RF-EMF-exposed animals in one of the seven chronic bioassays. Increased cancer incidence in exposed animals was noted in two of 12 studies with tumour-prone animals12 and 13 and in one of 18 studies using initiation-promotion protocols.14 Four of six co-carcinogenesis studies showed increased cancer incidence after exposure to RF-EMF in combination with a known carcinogen; however, the predictive value of this type of study for human cancer is unknown. Overall, the Working Group concluded that there is “limited evidence” in experimental animals for the carcinogenicity of RF-EMF.
Note that cancers that people theorize to be associated with exposure to nonionizing EM fields tend to be extremely rare, meaning that studying them is very difficult. This leads to a lot of uncertainty, because one must try to correlate very rare events with environmental effects. Therefore "limited evidence" does not mean "no", it just means that the effect is hard to measure and may or may not be significant given what we know.