There is much interest in the treatment world about the area of irreversible electroporation (IRE), which is a new way to damage cancer cells inside solid tumors, including prostate cancer tumors, by using an electric current. IRE, marketed as the NanoKnife, is a “new minimally invasive surgical technique that selectively kills tumor cells by using electrical fields to make holes in cell membranes,” according to Stony Brook School of Medicine which has begun using the method to treat certain types of pancreatic cancer. As exciting as the topic may be, this news release drops the ball on several levels. The Germany-based study claims to show that results from 265 patients showed fewer side effects with an image-guided IRE therapy for their prostate cancer than they would have had with other methods. But the claim is never backed up. Cost, valid evidence, alternatives and context are all missing from the release — hence the 1-star score.
Estimates put prostate cancer as the fifth-highest expenditure of all cancers in the United States, with a yearly cost of about $10 billion in 2010. Any treatment that would lower costs (such as hospitalization and surgery) and decrease side effects, such as impotence and incontinence, would make an enormous difference. This news release missed its chance to educate the public and practitioners in two ways: by promoting ahead of peer-review publication and by failing to include some context about the size of cost burden.
The release does not discuss costs.
The release does give a list of outcomes, and uses quantitative language to describe them, but there’s nothing to substantiate the claim that these outcomes are better than what would be achieved with a more conventional treatment approach. The release doesn’t mention outcomes like survival time that are obviously of critical importance to patients. And because this research has not been published in a peer-reviewed journal, the data cannot be judged as credible and acceptable by typical professional standards. The release does not tell us anything about the study protocol. It does state it was “an analysis of clinical data” so it wasn’t a controlled trial. Randomized and controlled trials are needed to achieve high standards in research.
The release makes several different claims about the superiority of this treatment method to others — but never brings up the potential of harm.
“The patients we have treated in the Prostata Center have had their cancers destroyed without the need for surgery, with a low incidence of side effects and in most cases have been back on their feet the next day,” the release states. [Italics ours].
The word “destroyed” is not typically used in medicine. Even if there is a “low incidence” of side effects, we would like to know what those rare side effects are.
Further, the news release provides no information about how side effects were measured (e.g., standardized measures completed by patients, physician assessments–which is not considered reliable), how many men actually completed reports of complications, the median length of follow-up–saying “up to 4 years” is very imprecise. (They could have been followed just 6 months, 1 year, and so on.) Another problem is that the recurrence group included men who had already been treated with surgery or radiation–which do cause erectile dysfunction and urinary incontinence. To interpret complication data the reader needs to know the level of urinary control and sexual function before the IRE treatment. The release also does not describe how recurrence was defined, whether all men were evaluated, and–again–the median length of follow up.
The release describes a study with data from 265 patients, and includes some details about their stage of cancer and their results in a follow-up of up to 4 years. But the release does not describe how the study was conducted which weakens the credibility of the data provided.
While we know the study was not randomized and controlled, we then looked for credible evidence about benefits. A big problem with the study is that T3 and T4 tumors (and the report does not indicate how many of the tumors were in these categories) have spread beyond the prostate and are not curable. This makes it very difficult to understand what the authors meant by “tumor control” and “recurrence.”
The release does not use disease mongering language.
The release did not identify funding sources for the research. Frehling is the director of a for-profit treatment center, Prostata.
We would have liked to see the release outline the typical alternatives for a patient presenting with prostate cancer, and explain how this image-guided IRE therapy compares to other therapies.
The release states: “Unlike other treatment procedures for prostate cancer therapy, image guided or IRE only destroys cells; vital tissue structures are not affected.” But it doesn’t outline side-by-side the alternatives for patients.
Currently, cryotherapy or other local therapies are not recommended as therapy for primary or recurrent prostate cancer due to lack of long-term data comparing these treatments with radiation and surgery, according to the National Comprehensive Cancer Network (NCCN). For patients with recurrent cancer, the typical treatments include hormone therapy, chemotherapy, immunotherapy, and radiopharmaceutical therapy. Treatment choice for recurrent cancer would depend upon the initial stage and whether “recurrence” meant biochemical progression (PSA increase) or clinical evidence of progressive or metastatic cancer.
In this release, the group studied was not described well enough to know which alternative therapies would have been appropriate.
A common problem with early-stage primary cancers is overtreatment. An appropriate option for many men with low-risk cancers is “active surveillance” — not receiving any active treatment because there is no evidence for benefit. We do not know how many of the study subjects had low-risk cancers.
When a release is all about a “new” therapy, it is important to establish whether this technology and expertise is available only in academic centers or more widely in the community or hardly at all and only in clinical research. This release does not tell us anything about when and where this might be made available. If the investigator is just now reporting up to 4 years of data on only 265 subjects then this is not widely available.
The release does not provide context about the use of IRE for prostate or other cancers. Readers could easily come away from this release thinking that this is the first time outcomes have been reported on the use of IRE for prostate cancer. But other researchers have been looking into this. Also, IRE has a longer track record of use in pancreatic cancer that wasn’t mentioned.
There are a few sentences in this release that we can’t confirm and sound unjustifiable. Here are two examples, with our comments in italics.
“Dr. Stehling has treated the most prostate cancer patients in the world using this image-guided treatment.”
We would have preferred the number of patients he has treated, rather than “most in the world.”
“Data found that the most common side effects are either eliminated or greatly reduced using image-guided treatment.”
We believe you can’t claim both “eliminated” and “reduced” at the same time. It is one or the other.