Talk:Cancer

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Former good article Cancer was one of the Natural sciences good articles, but it has been removed from the list. There are suggestions below for improving the article to meet the good article criteria. Once these issues have been addressed, the article can be renominated. Editors may also seek a reassessment of the decision if they believe there was a mistake.
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To Maintaining Low Blood Sugar as a New Cancer Treatment[edit]

— Preceding unsigned comment added by Evilstriver (talkcontribs) 08:21, 23 September 2009‎

Minor change to last paragraph of opening[edit]

I think that this sentence in the last paragraph of the opening should be changed.

Cancer is usually treated with chemotherapy, radiation therapy and surgery. Changed to: Cancer is usually treated with chemotherapy, radiation therapy and/or surgery. Every cancer treated is not treated by all three methods! Rainbowkey (talk) 18:20, 4 June 2014 (UTC)

Yes check.svg Done. Thanks for the heads-up. Quercus solaris (talk) 20:02, 4 June 2014 (UTC)

Causes of cancer[edit]

The current redirect is to Carcinogenesis (viz. Cancer#Pathophysiology). I think a redirect here to Cancer#Causes would be more appropriate. 109.156.204.159 (talk) 12:59, 11 July 2014 (UTC)

Agreed. I've noted at my project that Obesity and cancer is missing, unlike baccy and alcohol. Wiki CRUK John (talk) 13:42, 11 July 2014 (UTC)
Done. 109.156.204.159 (talk) 14:38, 11 July 2014 (UTC)

Cancer#Causes[edit]

The Causes section currently begins:

Cancers are primarily an environmental disease (currently unlinked) with 90–95% of cases attributed to environmental factors and 5–10% due to genetics.

Apart from a slightly pedantic concern that this is arguably an inappropriate reflection of the source [1], which does not explicitly state that cancer is principally an environmental disease, I'm concerned that this important statement about cancer preventability is open to simplistic misinterpretation by many readers. To start a section on Causes, wouldn't it a good idea to explain first that cancer etiology is generally multifactorial (genetic predisposition → environmental triggers, etc)? 109.156.204.159 (talk) 14:38, 11 July 2014 (UTC)

Yes, I don't like that - and HS says "absolute rubbish". Every word in "attributed to environmental factors and 5–10% due to genetics" opens a large question this glides over. I'd just cut for now. Very obscure journal too. Wiki CRUK John (talk) 17:32, 11 July 2014 (UTC)
Yes, the source is far from ideal. When a disease can be shown to be attributable to a given risk factor in a percentage of patients, it's ok [2] to say that the disease is due to that factor in those patients. However, the environmental disease claim is complicated [3] ... and I'm certainly going there now (the page is protected anyway, lol). Imo, the best place to start is with the multifactorial concept, as in the CRUK vademecum. I guess this section provides a further example of the sort of key area where skilled/expert CRUK input could really help improve our medical content in a genuinely NPOV way. 109.156.204.159 (talk) 19:10, 11 July 2014 (UTC)

Comment: I think a lay wikipedian could be forgiven for suspecting a deliberate POV split between this page and Carcinogenesis:

I think this apparent contradiction needs to be addressed, perhaps starting from the parent page here. 109.156.204.159 (talk) 12:40, 13 July 2014 (UTC)

"Cancer is a genetic disease" is I think true, but will lead most lay readers to take it that this means it is inherited, rather than caused by mutations or DNA damage (naturally occurring) etc within the lifetime of the patient (I'm well out of my comfort zone here). Environmental factors cause genetic changes, which cause cancer. The "5–10% due to genetics" is all or mainly inherited genetics. No POV I think, just things that need to be explained better. Wiki CRUK John/ Johnbod (talk) 20:41, 13 July 2014 (UTC)
Yes, the two statements I bullet-pointed are not actual contradictions; those two perspectives basically correspond to two levels of study (population / cellular). Editorially, I think we need to highlight the different levels/perspectives clearly on this page by introducing the Causes section better. Then, at the population level, there's the question of what proportion of cancers globally can reasonably be attributed to environmental/lifestyle factors. Maybe we need more cautious wording there. 109.156.204.159 (talk) 22:07, 13 July 2014 (UTC)

This is a bit complicated because words have multiple meanings. What's meant to be communicated is this:

  • About 5–10% of cancer cases are due (i.e., exclusively due) to hereditary factors. For example, the excess ovarian and breast cancer caused by BRCA mutations falls into this group.
    • Importantly, "hereditary" and "genetic" are not the same thing. Hereditary diseases are usually genetic, but genetic diseases are frequently not hereditary.
  • The rest are caused by non-hereditary factors.
    • "Non-hereditary" is called "environmental" in much of the literature.
    • This category includes:
      • "environment" in the ecological sense: skin-cancer-causing radiation from the Sun is part of our environment.
      • "environment" in the pollution sense: lung-cancer-causing smog is part of our environment.
      • "environment" in the personal lifestyle sense: what we eat and drink, and what we do during the day, is part of our environment.

I doubt that anyone really believes that this split between hereditary and non-hereditary factors is "absolute rubbish".

If you've got a better idea for how to express this concept, then I'd be happy to hear it. Perhaps it would be better to specify "hereditary genetics" or "hereditary factors" instead of the ambiguous word "genetics"? (The original addition was here.) WhatamIdoing (talk) 03:54, 14 July 2014 (UTC)

Thanks for that. Editorially, I think we need to avoid unintentionally giving the impression of a possible nature versus nurture dichotomy here. For that reason I've removed the "Cancer is a genetic disease" statement at the start of Carcinogenesis#Mechanisms; not because it's wrong per se, but because without adequate contextual explanation it can easily be misconstrued as genetic determinism. The editorial issue here is somewhat similar, imo. We need to restore/provide some sort of introduction/context to the "environmental" statement. For a start I think we could simply copyedit out the term "environmental disease", which does not appear in the cited source and is rather ambiguous (eg are we referring to some more or less authoritative list of 'environmental diseases'? [no]). Prior to that sentence, I think we need to provide a brief but properly sourced introductory explanation of the multifactorial character of cancer, reinstating the internal link to #Pathophysiology (or perhaps #Pathogenesis would be a more helpful heading there?), to help orientate the general reader. While doing this, we can mention the concepts of innate genetic predisposition and the triggering of the disease by environmental exposures (the 'Environmental epidemiology' page is the best current link I've been able to find to reference the usage here of the term environmental-exposure).

As regards the term "hereditary factors", I don't think it would be right to use that as a synonym for genetic factors, as genetic disorders can involve new mutations that are not inherited.

(On a related matter, I think PMID 24351322 might be a potentially useful source on this page, but it's behind a paywall.)
109.157.86.177 (talk) - previously 109.156.204.159 - 12:55, 14 July 2014 (UTC)

Cancer has genetic mechanisms and its causes are mostly not inherited. Doc James (talk · contribs · email) (if I write on your page reply on mine) 01:31, 15 July 2014 (UTC)
Well, sort of... You're (we're) using "causes" here in a particular epidemiological sense [4] referring to the necessary/sufficient conditions for a disease to manifest clinically; the "genetic mechanisms" of pathogenesis obviously involve cause and effect too, though at a different level. Editorially, this parent page needs to distinguish the two levels succinctly. Imo, the start of the #Causes section is the place to do this. 109.157.86.177 (talk) 09:25, 15 July 2014 (UTC)
We're have a very similar discussion at Talk:Pancreatic_cancer#Sentence_in_lede_needs_attention_of_subject_matter_expert, where for now I have substituted "....10% of cases are linked to inherited genes." in the lead in a comparable sentence. It would be great if we could agree terminology, even cut-and-paste phrasing, to use in such recurring situations. I was just reading this morning: "Cancer is fundamentally caused by inherited (germline) and acquired (somatic) mutations in cancer-causing genes." (my links obviously),[1] if that's any use. Wiki CRUK John (talk) 11:23, 15 July 2014 (UTC)
I'm not sure any ready-made solution on a cut-and-paste sort of basis is feasible here. Imo, as medical editors/writers we need to cultivate an awareness of how the meanings of the words and terms we read and report may vary according to the context in which they're used. And also to be aware of the sorts of difficulties (or misunderstandings) that our readers, in turn, may have in distinguishing the intended meanings of the words we use if we fail to provide the necessary context/explanation. 109.157.86.177 (talk) 12:12, 15 July 2014 (UTC)
  1. ^ Wolfgang, CL; Herman, JM; Laheru, DA; Klein, AP; Erdek, MA; Fishman, EK; Hruban, RH (2013 Sep). "Recent progress in pancreatic cancer.". CA: a cancer journal for clinicians 63 (5): 326. PMID 23856911. 
We have a section on pathophysiology / mechanism that deals with the mutations in DNA as steps towards cancer. The "cause" is the things that lead to these mutations. Some times they can be inherited but usually they are not. We use this sort of language in many articles, not just cancer related ones. Quotes are not needed around environmental thus removed. Doc James (talk · contribs · email) (if I write on your page reply on mine) 12:00, 15 July 2014 (UTC)
I'm not so sure about that, as the general usage of "environmental" refers to air pollution etc, not one's own smoking, obesity etc. The very stubby Environmental factor has no medical angle, while Environmental disease (virtually reference-free) starts off with a definition that appears to restrict it to diseases only caused by environmental factors (although it doesn't). Some work would give better things to link to. Wiki CRUK John (talk) 12:21, 15 July 2014 (UTC)
We describe what environmental means in the very next sentence. Have linked environmental disease but that page does need work. Doc James (talk · contribs · email) (if I write on your page reply on mine) 12:29, 15 July 2014 (UTC)
As I tried to suggest above, I think linking as environmental factors (without any scare quotes) is explanatory, in that it helps the reader understand what sorts of risk factors are being referred to. Imo, linking to the somewhat impressionistic 'Environmental disease' page doesn't really hit the mark on that one. 109.157.86.177 (talk) 13:04, 15 July 2014 (UTC)
Ok, "Environmental epidemiology|environmental factors" - but not environmental factors, yet anyway. Not sure where MOS stands on piping to something that is itself a title. Kill or cure on environmental factor? Wiki CRUK John (talk) 14:05, 15 July 2014 (UTC)
It's not that we tend to use the wrong words as such. It's that we sometimes collectively fail, imo, to clarify editorially the context in which we're using them. As on this page where we don't currently signal to the reader that the sort of thing biologists (among other people) rightly consider, on a pathogenetic level, to be "causes" are discussed further down the page (eg like this: "see #Pathophysiology"). One side effect of this habit is that we tend to get into lengthy talk-page discussions (as in "cancer"/"carcinoma", "premalignant lesions"/"malignant cells", etc) where the semantic key tends to escape us. 109.157.86.177 (talk) 12:51, 15 July 2014 (UTC)
It's very tricky. That's why I actually favour little standard bits one can slot into the many articles where the issues occur, varying as necessary. For cancers there are a fair number - eg in all the ones I've seen familiarity with the basic processes of histology/pathology is assumed, and in many staging also. Short plain explanations would be widely applicable. Wiki CRUK John (talk) 14:05, 15 July 2014 (UTC)
I can see where you're coming from. Perhaps as in this? I thought of suggesting a similar solution in the lead on the 'Lung cancer' page (primarily edited by Axl). But when I looked at how the detail of how that is currently worded I didn't feel so confident that linking "types" like that would actually be an improvement. 109.157.86.177 (talk) 15:18, 15 July 2014 (UTC)
In "Lung cancer", I wouldn't object to "The main histopathological types". Axl ¤ [Talk] 17:03, 15 July 2014 (UTC)

Arbitrary break - Etiology vs. Pathogenesis?[edit]

I guess the general problem might stem from an understandable reluctance to use a difficult term like "Etiology" as a heading, per normal review-writing practice. For the general Wikipedia reader we prefer the simpler word, "Causes". But "causes" isn't an actual synonym for "etiology". So, if we want to use the heading in that sense (as James at least seems to suggest here), I think we need to show what we're doing to the reader. Perhaps by using a standardized template (broadly per John's suggestion?) with an internal link to the "Pathophysiology" section.

Small note: Having said all that, I have to say the distinction made between the "Causes" and "Pathophysiology"/"Mechanism" sections in MEDMOS doesn't appear altogether clear-cut. As written, the "Causes" section invites content on "genetics" etc which may regard either pathogenesis or etiology.
109.157.86.177 (talk) 12:50, 16 July 2014 (UTC)

Yes we use causes and etiology as synonymous per using simple language. Simple language I agree is not perfect and cannot be made perfect. It is a trade off.
Genetics that is inherited would be part of "causes" while genetic changes that occur as part of the mechanisms of development would be part of the pathophysiology IMO. Doc James (talk · contribs · email) (if I write on your page reply on mine) 20:55, 16 July 2014 (UTC)

Split off causes[edit]

This article is about 10,000 words, which is the very upper end of WP:SIZE. It's so long that it's unlikely that anyone will read it in one sitting.

The longest sections are ==Causes== and ==Pathophysiology== (which is also very technical). Would anyone mind if we split off ==Causes== (leaving behind a four- or five-paragraph summary, including a list of the main categories of causes)? It could go in Causes of cancer (currently redirecting here) and also acquire the redirect Cause of cancer that is currently pointing at Carcinogenesis.

I think this would be a fairly quick change to make. I'd like to do something similar for the path section, but I think that would be more complicated. WhatamIdoing (talk) 20:12, 15 July 2014 (UTC)

I would be more in favor of splitting of pathophysiology / simplifying the pathophysiology section. IMO our readers have greater interest in causes than pathophysiology. Doc James (talk · contribs · email) (if I write on your page reply on mine) 20:20, 15 July 2014 (UTC)
Support WAID's proposal. I think it could be good to elicit input also from WikiProjects Genetics/MCB at least. From their points of view, much of the Pathophysiology section is almost certainly discussing "causes" too. Imo, just linking internally between the two sections (nothing dramatic there surely?) would help clarify our editorial approach.

Agree with WAID we also really can do with a separate 'Causes of Cancer' page anyway. Imo, that could (and probably should) cover perspectives both at the epidemiological (primary prevention) and pathogenetic (primary/secondary prevention) levels.If we wanted to restrict the 'Causes of Cancer' page to etiology rather than pathogenesis [10], I think we could perhaps do this by means of an appropriate dab header referring the reader to the 'Carcinogenesis' page for information on the pathogenetic causes of the disease. On reflection, I think we'd need a section at least on the pathogenetic aspect (obviously headed by a 'Main article:Carciniogenesis' template). I think it would be good to find some sort of reasonable consensus on that first among our projects to prevent avoidable misunderstandings later on.

Ultimately, I think we all need to try to step back from our individual viewpoints/backgrounds in the interests of our general readership. 2c, 109.157.86.177 (talk) 21:08, 15 July 2014 (UTC)

Support trimming Pathophysiology in preference to "Causes". But is the "Pregnancy" section really necessary here? I'd be inclined to just move that to its own article, so gaining some breathing space. Wiki CRUK John (talk) 12:29, 16 July 2014 (UTC)
We often have "special population" sections. For example see obesity. Pregancy is only 4 paragraphs. It it grows could see summarizing it in one paragraph and creating a subpage. Doc James (talk · contribs · email) (if I write on your page reply on mine) 20:53, 16 July 2014 (UTC)
5 paras in fact. If it affects 1 in 1000 pregnancies it affects, what, 1 in 3000 people, and there isn't all that much really decisive to say about it. I don't think it rates 4 paras here. Childhood obesity (including overweight) affects about 28% (and rising) of children in the UK. Wiki CRUK john/Johnbod (talk) 21:40, 16 July 2014 (UTC)
IMO the use of causes to mean etiology is the more common usage of the term. If we consistently use mechanisms for pathophysiology there should not be an issue. Doc James (talk · contribs · email) (if I write on your page reply on mine) 20:57, 16 July 2014 (UTC)
Circle frame.svg

How the article is divided

  Cause (23%)
  Pathophysiology (17%)
  Management (10%)
  Diagnosis (7%)
  Research (5%)
  Prevention (5%)
  Screening (5%)
  Signs and symptoms (4%)
  Epidemiology (4.5%)
  Society and culture (5.5%)
  History (4%)
  Definitions (1%)
  Prognosis (3.5%)
  Pregnancy (4%)
  Other animals (0.5%)
  Other (1%)

Here's a breakdown of what the article covers, by word count (excluding the lead). The largest wedge is ==Causes==. The second largest wedge is ==Pathophysiology==. The ==Pregnancy== section is only 4% of the article, so even blanking it completely would have little effect overall (other than making the article incomplete. Also, there should be a corresponding section for ==Children==).

If we want to have a noticeable effect on the article size, then we really have to focus on those bigger parts of the pie. It's true that I like the ==Causes== section. Since I wrote a good deal of it a few years ago, it's flattering to hear people say that they think readers will be interested in reading it. But I think it's time to split it off. WhatamIdoing (talk) 22:06, 16 July 2014 (UTC)

I could see splitting it off and summarizing what we have here more. I would go for 10 paragraphs rather than 4 though. Doc James (talk · contribs · email) (if I write on your page reply on mine) 22:40, 16 July 2014 (UTC)
  • There are two related but distinct questions being discussed here, which I think call for largely separate decisions:
  1. Do we need a 'Causes of Cancer'? [Imo, definitely yes!]
  2. How to balance this vital parent page so to make it as useful and accessible as possible to the lay general reader? [Hum, good question...]

Of course, WP:SUMMARYSTYLE is relevant to both. —109.157.86.177 (talk) 09:39, 17 July 2014 (UTC)

I've copied the content to the new page and fixed the redirect. The next little task is for someone to set importance ratings on Talk:Causes of cancer, and the next big task is to start summarizing/shortening the content of that section here. I'll take a baby step that way.
What do you all think about aiming for three subsections, roughly heredity, lifestyle, and non-lifestyle environment? WhatamIdoing (talk) 16:06, 17 July 2014 (UTC)

Characteristics/Hallmarks of cancer[edit]

This stuff is in twice: one below the lead and once (oddly) at the end of "Genetics" (with a fuller text). I suggest merging to the earlier position. Wiki CRUK John (talk) 10:02, 17 July 2014 (UTC)

Imo, that content is quite specific to this page, but is more suited to the Pathophysiology section (perhaps with an internal link from a statement at the top about the difficulty in providing a precise, universally accepted definition). Personally, I feel it would perhaps be more useful for the lay reader to start by providing some more general information about the broad spectrum of the clinical manifestations of cancer (ranging from highly aggressive conditions such as pancreatic cancer or malignant melanoma to basal cell carcinoma). Perhaps also to mention the relevance of cell type as well as organ. 109.157.86.177 (talk) 12:45, 17 July 2014 (UTC)
("Characteristics" is good imo, whereas "Hallmarks" isn't really a helpful metaphor here.) 109.157.86.177 (talk) 14:23, 17 July 2014 (UTC)

Other animals[edit]

I think this section, focusing on transmissible cancers in animals, looks a bit strange as it stands. An innocent reader might wonder whether cancer occurs elsewhere (See also?). Actually, Wikipedia content on animal diseases as a whole is a bit of a mystery to me. 109.157.86.177 (talk) 15:52, 17 July 2014 (UTC)

Unfortunately, vet med articles are a bit of a mystery to just about everyone. We've had a couple of good editors work on them in the past, but they tend to be focused on particular animals (e.g., horses or cats, but not animals in general), and I'm not aware of anyone working in that area these days. WhatamIdoing (talk) 00:54, 18 July 2014 (UTC)
Added a bit. Category:Veterinary_oncology seems, er, at least adequate. Wiki CRUK John (talk) 13:08, 18 July 2014 (UTC)
This recent study where a small trial on naturally occurring cancers in dogs preceded a successful treatment (with bacteria) of a single human patient might be worth giving an example of a research route. Wiki CRUK John (talk) 13:06, 19 August 2014 (UTC)

Cancer and alternative medicine/CAM[edit]

Here are a couple new articles from Medscape dealing with AM/CAM:

  • Citation template: <ref name=Stern>{{Citation |last=Stern |first=Victoria |date=02 September 2014 |title=Mythbusters: Complementary and Alternative Treatments in Cancer |publisher=''[[Medscape]]'' |url=http://www.medscape.com/viewarticle/830552_print |accessdate=07 September 2014 }}</ref>
  • Citation template: <ref name=Miller>{{Citation |last=Miller |first=Gabriel |date=02 September 2014 |title=Asking the Experts: Complementary and Alternative Medicine and Cancer |publisher=''[[Medscape]]'' |url=http://www.medscape.com/viewarticle/830553_print |accessdate=07 September 2014 }}</ref>

Registration is easy and free. Medscape is a good RS, sometimes as a MEDRS, and other times for expert opinions. -- Brangifer (talk) 17:10, 7 September 2014 (UTC)