Friday, 28 September 2012

Treating LMS: Part I

Over the last eighteen months or so I’ve spent a considerable amount of time researching my illness and its treatment. I thought it might be of interest to share a summary of my understanding from this research focusing on where new developments in treatment might be of help to me. I’ve decided to split this into two blog entries, the first looking at well established cancer treatments and the second at some of the newer therapies.

Classically there have been three main techniques for treating cancer, including LMS:
  1. Surgery. Surgical removal of cancerous tissue can be performed in order to cure the disease (by removing all trace of it from the body) or it can be palliative (removal of tumours that are causing the patient to suffer symptoms with the aim of relieving these). For LMS surgery is considered the ‘gold standard’ treatment and the best hope of a cure. For curative surgery to be viable it must be possible for the surgeon to remove all of the LMS tumours and a sufficient margin of healthy tissue surrounding them to ensure that all of the cancer cells have been excised.

    In my case curative surgery has never been judged a viable option as the cancer is in too many parts of my body, too close to vital tissues and, in my liver, takes the form of many ill defined and diffuse tumours. What’s more the fact that my cancer has already demonstrated the capability to spread to distant parts of my body means that surgery would be very, very unlikely to remove all the cancerous cells even if all the tumours visible on CT scans today could be removed.

    Whilst surgical techniques for removing tumours are improving all the time, for instance with the use of robots to assist surgeons in operating with greatly improved accuracy, nothing in my research makes me hopeful that curative surgery could become something of use to me based on these developments alone.

    Whilst it is extremely unlikely, should I have a near complete response to my current or a future chemotherapy treatment resulting in the vast majority of my cancer vanishing and leaving just a handful of tumours I would discuss curative surgery again with my oncologist. I should make it clear though that removal of all the tumours in my body is unlikely to remove all of the cancer cells so there would be a high probability of a reoccurrence. 

    Palliative surgery could be of use to me in the future, particularly in regard to the abdominal tumours I have which, if they should grow, could cause blockages in my digestive tract that could be life threatening if not removed.

  2. Radiotherapy: Solid tumours, such as those found in LMS, can be destroyed by exposing them to radiation. In the past Katie and I have discussed the use of radiation with my oncologist particularly in regard to its suitability to target my liver tumours. My oncologist consulted a colleague from the Royal Marsden’s sarcoma centre and they both agreed that the treatment would not be suitable in my case.

    As with surgery, radiotherapy techniques are improving all the time especially with the use of computer controlled machines to administer the treatment in safer and more accurate ways. However the number and diffuse nature of my liver tumours continues to make them unsuitable candidates for this kind of treatment.

    There is another, more fundamental factor that indicates against the use of radiotherapy in my case. There is evidence that cancer cells in which the TP53 gene is damaged may not respond well to radiotherapy as it is thought that radiotherapy kills cancer cells through a cellular pathway that requires functioning versions of this gene. Furthermore, for people with one mutated copy of TP53 in their normal, non cancerous cells there is an increased risk that exposure to radiation could cause additional cancers. 

  3. Chemotherapy: Chemotherapy is a systemic treatment that exposes all cells in the body to cytotoxic (cell killing) chemicals. These chemicals are generally designed to target cells that are dividing, a behaviour that is particular prevalent in cancer cells. All of the treatment I’ve received to date has been chemotherapy; I've just completed my 15th cycle of treatment today and have received 27 infusions of chemotherapy drugs in total.

    LMS is not the most responsive cancer to chemotherapy and most of the recognised drugs used to treat the disease have relatively low rates of response. Research also shows that the response rate to chemotherapy in LMS decreases with each different agent used. Cancers also have an annoying habit of evolving immunity to cytotoxic drugs to which they are exposed.

    There are a couple of significant areas of advance in chemotherapy treatments; the first is the introduction of new agents approved for use in LMS. Trabectedin, the drug that I am currently using, was only approved for use in the last few years. The second area, not to be underestimated, is that progress is gradually being made in finding ways to better control the side effects produced by these very toxic chemicals. The importance of this second point cannot be overstated given that many patients have to discontinue their use of chemotherapy treatment because of the severity of the side effects.

    There are a number of clinical trials running today that are looking at the efficacy of several new chemotherapy drugs or at the efficacy of combinations of drugs in sarcoma. Trials take several years to run and then the process for drug approval by NICE can also take some considerable time so even if some of these trials identify effective drugs it will be some time before they are available to be used outside of the trial environment.  The research that I’ve done doesn’t suggest that any of the drugs currently in trial are likely to provide significantly better response than the existing approved agents. 
In conclusion these classical approaches to cancer treatment, once curative surgery is removed as an option, are all essentially palliative in nature in LMS. Based on my research it seems highly improbably that any of these treatments are likely to offer, in the near future, a means to a cure in my case. That’s not to say there is no hope here at all but we’re looking at very, very long odds indeed; however the improbable sometimes happens, I guess I’m looking for a good ‘black swan’ event!

In the meantime systemic chemotherapy has been doing a useful job for me in terms of palliative treatment and I’m hoping that the Trabectedin continues to perform for many more cycles. Radiotherapy and surgery may be useful in the future depending upon the course of my disease and my requirements for symptom relief. Then of course there are the less well established treatment types which are the subject of my next post.

No comments:

Post a Comment