Cancer statistics

EOB-clinical-trialsWhat do cancer statistics really mean? In 2000 I was diagnosed with Stage 1 ovarian cancer. The statistics at the time stated that I had a 95% chance of surviving beyond five years. Although I did turn out to be one of those 95%, living for more than five years without a trace of cancer, it didn’t mean I was cured. Thirteen years later I felt a lump in my abdomen. I was just about to hike the Wicklow Way in Ireland so I ignored it, but on our return my hiking companion persuaded me to go to the doctor who said yes she could feel a lump. At which I burst into tears. “I’m only telling you what you already know,” she said.

Yes, my cancer had returned with one tumour attached to my abdominal wall and one deep in my liver. A biopsy confirmed they were tumours composed of ovarian cancer cells, even though I don’t have ovaries any more.

So that’s one statistic that’s a bit meaningless to the individual survivor. I had survived over five years, was declared cured, and discharged from the hospital. But thirteen years later the cancer was back again. This time I was told it would never go away, or if it did go into remission it would return. As I’m really careful around buses I presumed this meant it would eventually kill me.

I agreed to have the tumours removed and after six sessions of chemotherapy there was no obvious sign of cancer. But remember those darn statistics again. This time I had a 5% chance of surviving for five years or more. I agreed to participate in a clinical trial of a ‘maintenance’ drug – one that would reduce my chance of the cancer recurring, or I should say delay its return.

I diligently researched the efficacy of the drug which had been tested as a Phase 2 trial the year before. Phase 2 trials use small numbers of participants to evaluate the safety of a drug and whether the side effects are tolerable. Apparently it was tolerable so the pharma company was able to take it to Phase 3. The trial offered to me was available to hundreds of women worldwide and would test the efficacy – or whether the drug was working. I was happy to be a guinea pig on this ‘double blind’ trial. For every three women recruited two would get the trial drug and one would get the placebo. For several months I had no side effects so I thought I must be on the placebo. But after a while my red blood cell count began to plummet which is one of the known side effects of the trial drug. I couldn’t get up the stairs at home without having to sit down on the top step to recover. Nine months later I had a scan which found some new small tumours in my liver. The ‘success’ of the drug was not cure but delayed recurrence but I had no way of knowing whether it had been successful or not as there were no statistics to hand. All I knew was that I was disappointed.

Last week I looked up the drug and found the recently published results from my trial. Progression-free survival in my cohort of women was 9.3 months compared to 3.9 months for women on the placebo. Yay – I was a successful statistic as my own progression-free survival had been nine months. Should this make me believe in cancer statistics? Well, yes. But there are two points to make. Firstly, what does the ‘extra’ 5.4 months of being free from cancer actually mean and is it ‘worth it’? The quality of my life during those months was not great as I was out of breath much of the time and had to have several blood transfusions. Secondly, not all women on the drug were free from cancer for exactly 9.3 months – some had more time, others less. And the same goes for the women on the placebo.

In truth, cancer drug therapy is a lottery, especially at Stage 4 when there are all manner of trial drugs available to desperate patients. Clinicians know this and take pains to tell us that we, their individual patients, are not statistics. Taking this or that drug is likely to give us more time free from cancer than not taking it – but that’s not guaranteed.

I finished that trial at the beginning of 2015. Since then I’ve been on three more drug regimes. I agreed to go onto another rather vicious regime consisting of a cocktail of three different drugs, none of which ‘worked’. After that I participated in another trial where I received an old drug rather than the trial drug. It didn’t ‘work’. By this time my liver tumours were rather large. We tried a different drug which I’d taken before to some effect, and yes – that really did work well. It shrank the tumours drastically. One registrar got so excited he played around with my stats on his computer to bring up the graph of my CA125 levels – the ovarian cancer marker which shows up in a blood test. Over three years it had gone up and down like the stock exchange, but now it was right down to ‘normal’ levels (not like the current stock exchange!). That twenty-year-old drug had ‘worked’ to reduce my tumours.

I have had seven months free from chemo – the first time for three years. Now, judging by rising CA125 levels, the tumours have grown again, so when I see my consultant on Tuesday I am likely to be presented with a choice of more chemo.

Will I take it? Yes. Why? Because I am not a statistic and there’s always hope.

 

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