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Medical Forum / Diseases and Disorders / Cancer / March 2005"Early" and "Late" Cancers
I've posted on this topic before, but there have been a lot of posts recently about "small" and "early" cancers, and the purported benefits of catching primary cancers and recurrences early. Now, all other things being equal, it is certainly more likely that a primary cancer can be cured when it is smaller rather than larger, but the issue is rather more complex. Recurrences after primary treatment are not the same as small primary cancers, and are often incurable, and the benefit of finding them when they are "small" is to say the least questionable. 1) Cancers start (presumably) with a single "clonogenic" cell. This multiplies by dividing, so the second generation is 2 cells, the third is 4, the fourth is 8, etc, etc. This is called geometric growth. 2) The smallest cancer detectable reliably by modern imaging techniques is about 1cm in size, let's say 1 cc in volume, 1 gram in mass. 3) A 1cm cancer contains about 10^9 cells. In order to get to this number, the original cancer cell has produced about 30 generations of progeny, so the cancer is 30 generations old. 4) A cancer weighing 1 kilogram is likely to be a threat to life - certainly a cancer of 2 kg would be. This means the total cancer, primary and metastases lumped together. 5) For a 1gram cancer to become a 1 kilogram cancer only requires 10 doublings. For 2 kilograms, only 11 doublings. 6) So a 1 gram cancer is already 3/4 through it's natural life cycle, and in that sense is already an "advanced" cancer. 7) If a treatment leads to a partial response, it maybe knocks the cancer back 2 or 3 doublings. That would shrink a 1kg cancer to 500gm, or 250 gm. Very impressive, but not very meaningful in terms of the cancer's "life cycle". "Partial responses" may be valuable in terms of symptoms, but usually don't offer any survival benefits. 8) Even a "complete remission" may only mean that a 1kg cancer has been knocked back 10 generations out of 40, so that is now smaller than the limits of resolution of our imaging. Some complete remissions are cures, but many are not. 9) These maths assume a "perfect" cancer. There is no such thing, though. All cancers lose cells which die - in many cancers this proportion can be 90% or more - so a 1 cm cancer may be older than 30 generations, and a 1 kg cancer may be much older than 40 generations. I believe this is something people need to think about when considering responses to treatment and what they mean. > I've posted on this topic before, but there have been a lot of posts > recently about "small" and "early" cancers, and the purported benefits of [quoted text clipped - 45 lines] > I believe this is something people need to think about when considering > responses to treatment and what they mean. Depressing even if totally accurate:-(( OTOH complete cure IS possible. My lady had a mastectomy followed by chemo 30 years ago. That cancer has never re-appeared, Unfortunately she developed Ovarian about four years ago and that one is "winning". Steph; you have a series of questions to help decide if chemo is worth doing. I wonder if that is at a web site. If it is perhaps you could add the link to your sig. I believe I learned about it from a post by J. If there is a site the link should be of the form http://www.anywhere.xxx which makes it a hot link in almost all readers TIA LB > Depressing even if totally accurate:-(( > OTOH complete cure IS possible. My lady had a mastectomy followed by chemo 30 > years ago. That cancer has never re-appeared, Unfortunately she developed > Ovarian about four years ago and that one is "winning". I'm sorry to read that. More information is known now. I see on the breast cancer newsgroup (for the past few years, at least), they discuss taking ovarian suppressing medications and/or hysterectomy. Maybe the word's not been getting out and/or people can get ovarian cancer without previously having had breast cancer. I see them sometimes post that they've removed one ovary. (so they can still have children). I understand if they're young and want children (and/or are worried about osteoporosis), but what's the point of having children, where the person might not be around long enough to even raise them (recurrence), much less enjoy them as adults and their grandchildren. <end my rant> > Steph; you have a series of questions to help decide if chemo is worth doing. I > wonder if that is at a web site. If it is perhaps you could add the link to > your sig. > I believe I learned about it from a post by J. > If there is a site the link should be of the form http://www.anywhere.xxx which > makes it a hot link in almost all readers http://tinyurl.com/4akk6 Google archives I don't know if he can handle a signature (or not). For instance, if he wanted to post to another newsgroup, can it be set for just specific newsgroups? J > > Depressing even if totally accurate:-(( > > OTOH complete cure IS possible. My lady had a mastectomy followed by chemo 30 [quoted text clipped - 24 lines] > specific newsgroups? > J I use a little program called Robotype found on PC Magzine website. It was free when I got it but may now cost a few bucks. Very handy as it lets one use short abreviations to generate long stuff. ";g" can generate Please don't generalize. There is only ONE true generalization... "There are exceptions to ALL generalizations". or ";x" to get Experience is the best and most expensive teacher. That way I can put in sigs as needed. LB For help with Mozilla, FireFox or Thunderbird try these places http://www.ufaq.org/ http://sillydog.org/ http://mozilla.org http://ilias.ca/ > > > Steph; you have a series of questions to help decide if chemo is worth doing. I > > > wonder if that is at a web site. If it is perhaps you could add the link to [quoted text clipped - 17 lines] > > or ";x" to get I don't understand ??? Which generalization and what's the ",x" for ? > Experience is the best and most expensive teacher. > [quoted text clipped - 6 lines] > http://mozilla.org > http://ilias.ca/ Well, thanks, but what we would want is for Outlook Express. That's what Steph uses, if he's willing. J > > > > Steph; you have a series of questions to help decide if chemo is worth doing. I > > > > wonder if that is at a web site. If it is perhaps you could add the link to [quoted text clipped - 34 lines] > That's what Steph uses, if he's willing. > J Robotype will work with anything. It is what's call a macro processor or shorthand. The ";" (semicolon) is a flag that tells Robotype a macro is coming. Whatever follows is the identification of the macro. So when I type ";mt" followed by a space I get "I was gratified to be able to answer promptly, and I did. I said I didn't know." --Mark Twain The generalization thing was just a sample of what robotype lets one do. The user defines the flag (in my case a semicolon), the short ids and the stuff that replaces it. Robotype is one of several that I know about and is about the easiest to use. > > > > > Steph; you have a series of questions to help decide if chemo is worth doing. I > > > > > wonder if that is at a web site. If it is perhaps you could add the link to [quoted text clipped - 16 lines] > The user defines the flag (in my case a semicolon), the short ids and the stuff that replaces > it. Robotype is one of several that I know about and is about the easiest to use. Thanks for explaining. I like macros. Used to create and use them a lot - cut tasks/projects into less than half the work. Unfortunately they charge for Robotype. I found another solution and it's free. :-) J - - - Ask Steph if your cancer/stage is curable. Then please see http://tinyurl.com/4akk6 for his algorithm about treatment decisions Steph's" Questions to Ask" > > > > > > Steph; you have a series of questions to help decide if chemo is worth doing. I > > > > > > wonder if that is at a web site. If it is perhaps you could add the link to [quoted text clipped - 28 lines] > Then please see http://tinyurl.com/4akk6 for his algorithm about treatment decisions > Steph's" Questions to Ask" But, but, but!!! You did not say what the solution is or give us a URL <bg> LB > J: > > - - - [quoted text clipped - 5 lines] > > You did not say what the solution is or give us a URL <bg> That's a url (tinyurl) which goes to Google archives. I use notepad. <g> I keep a notepad file open on my desktop and just copy and paste the signature that I want to use. J > > J: > > > - - - [quoted text clipped - 10 lines] > I keep a notepad file open on my desktop and just copy and paste the signature that I want to use. > J I see said the blind man to his deaf wife! Robotype is much easier and probably more fun. LB >> Depressing even if totally accurate:-(( >> OTOH complete cure IS possible. My lady had a mastectomy followed by [quoted text clipped - 36 lines] > specific newsgroups? > J You're my sig, J! > >> Depressing even if totally accurate:-(( > >> OTOH complete cure IS possible. My lady had a mastectomy followed by [quoted text clipped - 38 lines] > > You're my sig, J! Yes, but what if J is away?? LB >> >> Depressing even if totally accurate:-(( >> >> OTOH complete cure IS possible. My lady had a mastectomy followed by [quoted text clipped - 49 lines] > > LB Do a google for "Steph's Questions to Ask" > <LB@notmine.com> wrote . > [...] [quoted text clipped - 16 lines] > > > Do a google for "Steph's Questions to Ask" Found a faster way. J - - - Recommended Links or ask me - I'll find what you are looking for http://www.cancersupporters.com/asc/links.html I've heard somewhere that having children is a triumph of hope over experience! There are a lot of reasons people might think twice (or more) about having kids because "I might not be around for them" -- but they still go ahead optimistically. And it often works out. And sh.t happens even to perfectly healthy people who have no reason to think they won't be around to see their grands & great-grands growing up. There are no guarantees one way or the other. <end my rant> bj > I understand if they're young and want children (and/or are worried about > osteoporosis), but what's the point of having children, where the person > might not > be around long enough to even raise them (recurrence), much less enjoy > them as > adults and their grandchildren. <end my rant> > I've posted on this topic before, but there have been a lot of posts > recently about "small" and "early" cancers, and the purported benefits of [quoted text clipped - 45 lines] > I believe this is something people need to think about when considering > responses to treatment and what they mean. Yes, this is all Oncology 101. Most people who pontificate about how conventional medicine cannot cure many cancers simply don't realize that most cancers ARE advanced cancers by the time they are detected.  SignatureOrac |"I am not *trying* to tell you anything. I am simply not | interested in trying to compensate for your amazing lack | of observation." | http://oracknows.blogspot.com I really wonder how useful it is to think in these terms. The definition of an advanced cancer here seems to be anything that is detectable. A 1cm breast cancer lump would be advanced by your definition (being 3/4 of the way through a cycle which could ultimately kill the patient) but as far as the patient is concerned surely such a tumour is in its very early stages and could be very curable. I don't think it would be particularly useful - or meaningful - to tell such a patient that their cancer is advanced. With regard to treating advanced cancers - I struggle with the idea that reducing a 1kg tumor down to 500g is not a significant event. I know only a few doublings have been lost, but how meaningful is this really? If 1kg of cancer in a patient's liver will cause liver failure and death, surely a reduction to 500g would delay this? Surely reductions in cancer bulk, whilst certainly not equivalent to cure, are important in terms of how long a patient will survive? > I've posted on this topic before, but there have been a lot of posts > recently about "small" and "early" cancers, and the purported benefits of > catching primary cancers and recurrences early. > > Now, all other things being equal, it is certainly more likely that a > primary cancer can be cured when it is smaller rather than larger, but the > issue is rather more complex. Recurrences after primary treatment are not [quoted text clipped - 26 lines] > Very impressive, but not very meaningful in terms of the cancer's "life > cycle". "Partial responses" may be valuable in terms of symptoms, but > usually don't offer any survival benefits. > [quoted text clipped - 10 lines] > I believe this is something people need to think about when considering > responses to treatment and what they mean. >I really wonder how useful it is to think in these terms. > [quoted text clipped - 8 lines] > particularly useful - or meaningful - to tell such a patient that their > cancer is advanced. A 1cm breast cancer is "early" compared to a metastatic cancer, and that is the term I use with my patients. But patients naturally assume that a 1 cm cancer is 1000 times "earlier" than a 1kg tumour. I'm just putting that myth to rest. Understanding the truth is a good thing generally > With regard to treating advanced cancers - I struggle with the idea > that reducing a 1kg tumor down to 500g is not a significant event. I > know > only a few doublings have been lost, but how meaningful is this really? Only 1 doubling, actually. > If 1kg of cancer in a patient's liver will cause liver failure and > death, > surely a reduction to 500g would delay this? Surely reductions in > cancer > bulk, whilst certainly not equivalent to cure, are important in terms > of how long a patient will survive? Which is why chemotherapy may well improve quality of life in selected patients. Sadly there is little or no evidence that this kind of response leads to any survival benefit for most common cancers. > > If 1kg of cancer in a patient's liver will cause liver failure and > > death, [quoted text clipped - 6 lines] > patients. Sadly there is little or no evidence that this kind of response > leads to any survival benefit for most common cancers. I believe you but I am a bit baffled. Presumably what kills a patient is the size of the cancer more than anything. The cancer reaches such a size that it interferes with critical bodily functions. So how is it that chemo drugs are able to reduce the size of a tumour without simultaneously extending the patient's life? Greg >> > If 1kg of cancer in a patient's liver will cause liver failure and >> > death, [quoted text clipped - 17 lines] > > Greg Cancers kill from many effects. Mass effects leading to death by interfering with critical bodily functions is actually not that common. Widely metastatic cancers have significant metabolic effects, many of which are poorly understood. >> I believe you but I am a bit baffled. Presumably what kills a patient >> is the size of the cancer more than anything. The cancer reaches such [quoted text clipped - 3 lines] >> >> Greg Don't forget that the chemo itself can be and usually is highly toxic and does significant damage causing debility which may take months for a 'healthy' person to recover from. If you are already debilitated then any benefit may well be offset. There is a point beyond which chemo causes as much or more damage than the cancer and you end up compounding the problem. You really have to be fit to cope with chemo. Using chemo at later stages may be useful for symptom control but even then only if less debilitating things have failed. Even in the earlier stages the onc would have to have some really good stats to convince me. MIKE > 2) The smallest cancer detectable reliably by modern imaging > techniques is about 1cm in size, let's say 1 cc in volume, 1 gram in > mass. Can you confirm 1cm? My onc said resolution of CT/MRI scans was about 1mm and this would be about the size of a 30 generation cancer with no loss of cells. Perhaps I'm mixing up scanner resolution and detectable cancer size? Alf >> 2) The smallest cancer detectable reliably by modern imaging techniques >> is about 1cm in size, let's say 1 cc in volume, 1 gram in mass. [quoted text clipped - 6 lines] > > Alf 1cm has been the quoted limit for some time. Smaller lesions can be detected, but can't be characterised easily. It is true that modern scanners are seeing smaller lesions, but the radiologist doesn't usually know what they are >> Can you confirm 1cm? > 1cm has been the quoted limit for some time. Smaller lesions can be > detected, but can't be characterised easily. Thanks Steph. I tend to ask onc (and surgeon) too many questions and I know their time is scarce. This group is good for surplus Qs ;-) Alf > >> Can you confirm 1cm? > > 1cm has been the quoted limit for some time. Smaller lesions can be [quoted text clipped - 5 lines] > > Alf If your onc is part of a group look around for a nurse-practitioner - almost a doctor. They tend to be very good at communicating. LB > If your onc is part of a group look around for a > nurse-practitioner - > almost a doctor. They tend to be very good at communicating. Just the one onc + underling, 1 doc and 6 nursing staff in my (UK) chemo unit. All excellent as far as I'm concerned altho' nurses are a bit shy of answering some Qs incase they step on Onc's toes. Alf |
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