The non-curative nature of treatments for metastatic prostate cancer

In light of an article published in this week’s issue of the New England Journal of Medicine, we wish to be absolutely clear for our readers that no currently available form of treatment (including chemotherapy, androgen deprivation therapy [ADT], or other treatment) has ever been shown to cure the vast majority of metastatic prostate cancers.

The article by Weeks et al.  in the New England Journal does not address prostate cancer. What it shows is the following:

  • The authors studied 1,193 patients participating in the Cancer Care Outcomes Research and Surveillance (CanCORS) study (a national, prospective, observational cohort study).
  • These patients were all alive 4 months after being newly diagnosed with metastatic (stage IV) lung or colorectal cancer.
  • All patients were given appropriate chemotherapy for treatment of their condition.
  • 69 percent of the lung cancer patients did not appear to understand that chemotherapy was not at all likely to cure their cancer
  • 81 percent of the colorectal cancer patients did not appear to understand that chemotherapy was not at all likely to cure their cancer.

The article goes on to report other data related to the impact of patients’ ethnicities and patients’ perceptions of the quality of their communication with their physicians on the patients’ expectations about chemotherapy.

The idea that chemotherapy is curative for the treatment of late stage cancer of most forms is highly inaccurate, although there are exceptions to that general rule. As one example, metastatic testicular cancer can be cured — regularly — with chemotherapy. That is absolutely not the case for most people with stage IV breast, prostate, lung, colorectal, bladder, and other relatively common forms of cancer. For most such patients, the best that is possible is that chemotherapy may be able to induce a remission for a limited period of time.

In the case of evident metastatic (TxNxM1 or stage IV) prostate cancer, no form of treatment currently being applied to treat this condition has ever been shown to be curative except under exceptional circumstances. In general, the known forms of therapy (from standard ADT to complex new drug combinations that may include anything from enzalutamide to cabazitaxel) have, at best, in most cases, been shown to delay the progression of disease for a period of time. Of course that period of time may be a very long time for some men, and we are certainly not suggesting that treatment for late stage prostate cancer is ineffective. But equally, it is very rarely curative.

Who might reasonably be expected to be cured of stage IV prostate cancer? Well, the man with the greatest hope of such a possibility is likely to be someone whose primary tumor (in the prostate) can be removed or otherwise eliminated, who has negative lymph nodes, who has a single, well-defined, and relatively small bone metastasis that can be thoroughly radiated with targeted radiation therapy and who receives subsequent androgen deprivation (and possibly chemotherapy too) to eliminate any other small amounts of circulating prostate cancer tumor cells before they are able to actually adhere to other tissues outside the prostate and cause further metastasis. However, such cases are relatively rare.

The reason we wish to be very blunt about the facts above is that unreasonable confidence in modern therapies for cancer can be as devastating to patients and families as the actual disease. Most men with metastatic prostate cancer do die of their cancer — unless they die of some other condition before the cancer can kill them.

Back in the late 1980s and early 1990s, before any form of chemotherapy had been shown to have clinical effect in men with advanced prostate cancer, the onset of castration-resistance (when the PSA levels started to rise in men on various types of ADT), was well understood to imply that the only remaining care available was entirely palliative, and was designed to minimize or prevent pain associated with bone metastasis. The availability today of new forms of androgen deprivation (with enzalutamide and abiraterone) and chemotherapy (with docetaxel and cabazitaxel), not to mention drugs like sipuleucel-T and the dozens of other products in clinical trials, may be giving many people the idea that we can now regularly cure stage IV prostate cancer, just as they seem to have the idea that chemotherapy can cure stage IV lung and colorectal cancer.

The “New” Prostate Cancer InfoLink has no desire to take away hope. New therapies are extending lives among men with stage IV prostate cancer; as we extend those lives, additional new therapies do come along with the capacity to extend lives further; some men diagnosed with metastatic prostate cancer may live for a decade or more after such a diagnosis today (an extraordinarily rare event in the early 1990s). As yet, however, curative treatment of metastatic prostate cancer can never be promised, and any physician who implies that any therapy for metastatic disease may save a patient’s life had better be talking about the exceptions like the man described above as opposed to the majority of men (who will have widely disseminated metastatic disease, even if only a couple of metastases may be evident on a bone scan).

4 Responses

  1. Yes, it is very sad to hear of people talking as if all these hot new drugs (enzalutemide, cabazitaxel, abiraterone) are actually a cure. I know I am not going to get “better,” but a few more months, ideally years, with a decent QOL is very welcome.

  2. Great article; one comment:

    The statement ” … did not appear to understand that chemotherapy was not at all likely to cure their cancer” is slightly different from the statement actually contained in the NEJM article: “did not report understanding that chemotherapy was not at all likely to cure their cancer”.

    Some patients may have understood, but may not have reported that they understood. Either way, the need for educating patients is very obvious and it is great that this article contributes to making prostate and possibly other cancer patients understand what they are up against. With new drugs for metastatic cancer coming up at an increasing rate, hopefully we are not too far from a real breakthrough.

  3. When are we going to get the latest results on the patients who received Provenge treatment? Some time has past and by now there must be quite a few recipients, I am one of them.

  4. Quite well-formulated, Sitemaster. This is why I told a doctor several days ago that, should the prostate cancer I was apparently successfully treated for ever recur as M1, I would refuse any further treatment. The doctor said I was too pessimistic. I replied: ‘No, I am a realist, an atheist, a physicalist, and can read. I understand the difference between “with curative intent” and “without curative intent.”‘ I have no desire to postpone death and have access to euthanasia in two countries.

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