ノート/テキストマイニング
訪問者数 784      最終更新 2011-01-14 (金) 17:11:47
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次の思考実験

それぞれのabstractの中で、「colorectal cancer」と「aspirin」の<つながり具合>または<関係>を探そう。そのときの戦略として、
(1)もし同一の文の中に「colorectal cancer」と「aspiprin」が両方出て来れば、それらの間の関係を抽出・解析する。最も優先度を高く考えよう。
(2)どちらか一方しか出て来ない文の場合、それぞれの語の周囲の単語X(名詞?)との関係を抽出解析し、その単語Xを介して「colorectal cancer」と「aspirin」がつながるかどうか、もしつながればどういう関係かを解析する。つまり、媒介単語Xを仲介とした2語の関係を考える。Xは複数候補あるかもしれない。

最終的に求める結果は、対象論文について「aspirin」が「colorectal cancer」の診療治療に関わる("clinical")かどうかの判定、とする。(この判定の定義は未だいい加減で、やっていくうちに決まればいいと思っている。)

論文(iii)

Effect of daily aspirin on long-term risk of death due to cancer: analysis of individual patient data from randomised trials.

BACKGROUND:
Treatment with daily aspirin for 5 years or longer reduces subsequent risk of colorectal cancer.
Several lines of evidence suggest that aspirin might also reduce risk of other cancers, particularly of the gastrointestinal tract, but proof in man is lacking.
We studied deaths due to cancer during and after randomised trials of daily aspirin versus control done originally for prevention of vascular events.

METHODS:
We used individual patient data from all randomised trials of daily aspirin versus no aspirin with mean duration of scheduled trial treatment of 4 years or longer to determine the effect of allocation to aspirin on risk of cancer death in relation to scheduled duration of trial treatment for gastrointestinal and non-gastrointestinal cancers.
In three large UK trials, long-term post-trial follow-up of individual patients was obtained from death certificates and cancer registries.

RESULTS:
In eight eligible trials (25 570 patients, 674 cancer deaths), allocation to aspirin reduced death due to cancer (pooled odds ratio [OR] 0.79, 95% CI 0.68-0.92, p=0.003).
On analysis of individual patient data, which were available from seven trials (23 535 patients, 657 cancer deaths), benefit was apparent only after 5 years' follow-up (all cancers, hazard ratio [HR] 0.66, 0.50-0.87; gastrointestinal cancers, 0.46, 0.27-0.77; both p=0.003). The 20-year risk of cancer death (1634 deaths in 12 659 patients in three trials) remained lower in the aspirin groups than in the control groups (all solid cancers, HR 0.80, 0.72-0.88, p<0.0001; gastrointestinal cancers, 0.65, 0.54-0.78, p<0.0001), and benefit increased (interaction p=0.01) with scheduled duration of trial treatment (<=7.5 years: all solid cancers, 0.69, 0.54-0.88, p=0.003; gastrointestinal cancers, 0.41, 0.26-0.66, p=0.0001).
The latent period before an effect on deaths was about 5 years for oesophageal, pancreatic, brain, and lung cancer, but was more delayed for stomach, colorectal, and prostate cancer.
For lung and oesophageal cancer, benefit was confined to adenocarcinomas, and the overall effect on 20-year risk of cancer death was greatest for adenocarcinomas (HR 0.66, 0.56-0.77, p<0.0001).
Benefit was unrelated to aspirin dose (75 mg upwards), sex, or smoking, but increased with age-the absolute reduction in 20-year risk of cancer death reaching 7.08% (2.42-11.74) at age 65 years and older.

INTERPRETATION:
Daily aspirin reduced deaths due to several common cancers during and after the trials.
Benefit increased with duration of treatment and was consistent across the different study populations.
These findings have implications for guidelines on use of aspirin and for understanding of carcinogenesis and its susceptibility to drug intervention.

まず、

aspirinとcolorectal cancer (or gastrointestinal cancer) の共起している文は、
Treatment with daily aspirin for 5 years or longer reduces subsequent risk of colorectal cancer.

(ROOT
 (FRAG
   (NP (NNP BACKGROUND))
   (: :)
   (S
     (NP
       (NP (NNP Treatment))
       (PP
         (IN with)
         (NP
           (NP (JJ daily) (NN aspirin))
           (PP
             (IN for)
             (NP (NP (CD 5) (NNS years)) (CC or) (NP (JJR longer)))))))
     (VP
       (VBZ reduces)
       (NP
         (NP (JJ subsequent) (NN risk))
         (PP (IN of) (NP (JJ colorectal) (NN cancer))))))
   (. .)))

Several lines of evidence suggest that aspirin might also reduce risk of other cancers, particularly of the gastrointestinal tract, but proof in man is lacking.

(ROOT
 (S
   (S
     (NP
       (NP (JJ Several) (NNS lines))
       (PP (IN of) (NP (NN evidence))))
     (VP
       (VBP suggest)
       (SBAR
         (IN that)
         (S
           (NP (NN aspirin))
           (VP
             (MD might)
             (ADVP (RB also))
             (VP
               (VB reduce)
               (NP
                 (NP (NN risk))
                 (PP
                   (IN of)
                   (NP
                     (NP (JJ other) (NNS cancers))
                     (, ,)
                     (ADVP (RB particularly))))
                 (PP
                   (IN of)
                   (NP (DT the) (JJ gastrointestinal) (NN tract))))))))))
   (, ,)
   (CC but)
   (S
     (NP (NP (NN proof)) (PP (IN in) (NP (NN man))))
     (VP (VBZ is) (VP (VBG lacking))))
   (. .)))

あとは、cancerのみを許せば In eight eligible trials (25 570 patients, 674 cancer deaths), allocation to aspirin reduced death due to cancer (pooled odds ratio [OR] 0.79, 95% CI 0.68-0.92, p=0.003).

(ROOT
 (FRAG
   (NP (NNS RESULTS))
   (: :)
   (S
     (PP
       (IN In)
       (NP
         (NP (CD eight) (JJ eligible) (NNS trials))
         (PRN
           (-LRB- -LRB-)
           (NP
             (NP (QP (CD 25) (CD 570)) (NNS patients))
             (, ,)
             (NP (CD 674) (NN cancer) (NNS deaths)))
           (-RRB- -RRB-))))
     (, ,)
     (NP (NP (NN allocation)) (PP (TO to) (NP (NN aspirin))))
     (VP
       (VBD reduced)
       (NP (NN death))
       (PP (JJ due) (TO to) (NP (NN cancer)))
       (PRN
         (-LRB- -LRB-)
         (NP
           (NP
             (NP
               (NP (JJ pooled) (NNS odds) (NN ratio))
               (PRN (-LRB- -LRB-) (NP (NNP OR)) (-RRB- -RRB-)))
             (NP
               (NP (CD 0))
               (. ?)
               (NP (CD 79) (, ,) (CD 95) (NN %) (NN CI) (NNS 0))
               (. ?)
               (NP (CD 68-0))
               (. ?)))
           (NP (CD 92)))
         (, ,)
         (S
           (NP (NN p))
           (VP (JJ =) (NP (INTJ (UH 0) (. ?)) (NP (CD 003)))))
         (-RRB- -RRB-))))
   (. .)))

である。RESULTSの二番目の文
The latent period before an effect on deaths was about 5 years for oesophageal, pancreatic, brain, and lung cancer, but was more delayed for stomach, colorectal, and prostate cancer.
では、aspirinという言葉が出てこない(an effectと言うだけ。文脈で分っているということか?)

(言えること?)

論文(i)

Cyclooxygenase as a Target for Colorectal Cancer Chemoprevention.

Colorectal cancer (CRC) is one of the most common neoplasia in Western countries and the second leading cause of cancer-related death.
The vast majority of cases belong to sporadic forms, whereas a small but relevant proportion of them corresponds to inherited disorders, i.e. familial adenomatous polyposis and Lynch syndrome.
These individuals with germline mutations in cancer-promoting genes, along with those who had already developed a colorectal neoplasm, either adenoma or carcinoma, stand to benefit from chemopreventive interventions.
A large body of evidence indicates that the use of aspirin and other non-steroidal anti-inflammatory drugs (NSAID) can reduce the risk of CRC.
Experimental studies have demonstrated that these drugs decrease the incidence of carcinogen-induced colon tumors in rodents, and several epidemiological investigations and therapeutic trials have also shown a 40-50% reduction in the risk of colorectal adenoma and cancer in individuals taking NSAIDs.
Moreover, patients with familial adenomatous polyposis taking sulindac or celecoxib experience a reduction in adenoma size and number.
The chemopreventive effects of NSAID are largely related to inhibition of cyclooxygenase-2 (COX-2), the inducible isoform of cyclooxygenase that catalyzes the conversion of arachidonic acid to prostaglandins.
COX-2 overexpression is a frequent, but not universal event in colorectal neoplasms.
Indeed, approximately 50% of adenomas and 80% of CRC express high levels of COX-2 mRNA and protein in neoplastic tissue.
In this article, we will review the role of cyclooxygenase as a target for CRC chemoprevention, with special attention to the use of selective and non-selective COX-2 inhibitors in both individuals genetically predisposed and those who have already developed a colorectal neoplasm.

まず、

colorectal cancer (neoplasm) と aspirin が同じ文にでてくる場合は、1文だけあって、
A large body of evidence indicates that the use of aspirin and other non-steroidal anti-inflammatory drugs (NSAID) can reduce the risk of CRC.

この文の文法構造は、

(ROOT
 (S
   (NP
     (NP (DT A) (JJ large) (NN body))
     (PP (IN of) (NP (NN evidence))))
   (VP
     (VBZ indicates)
     (SBAR
       (IN that)
       (S
         (NP
           (NP (DT the) (NN use))
           (PP
             (IN of)
             (NP
               (NP
                 (NN aspirin)
                 (CC and)
                 (JJ other)
                 (JJ non-steroidal)
                 (JJ anti-inflammatory)
                 (NNS drugs))
               (PRN (-LRB- -LRB-) (NP (NNP NSAID)) (-RRB- -RRB-)))))
         (VP
           (MD can)
           (VP
             (VB reduce)
             (NP
               (NP (DT the) (NN risk))
               (PP (IN of) (NP (NNP CRC)))))))))
   (. .)))

単語aspirinとcolorectal cancer (ここではCRC)とのつながり具合・骨格は

       (S
         (NP
           (NP (DT the) (NN use))
           (PP
             (IN of)
             (NP
               (NP
                 (NN aspirin) )))
         (VP
           (MD can)
           (VP
             (VB reduce)
             (NP
               (NP (DT the) (NN risk))
               (PP (IN of) (NP (NNP CRC))))))))

で、まず「aspirinのuseがCRCのriskをreduceする」ということを言っているらしいことは分る。
その外側(A large body of evidence indicates that ) が「成り立たない」とか「違う」とか言っていると、結論が逆になるので、最終的には確認する必要があるだろう。

では、この1つの文がabstract全体に占める位置付けを、どう見つけることができるか?ここで最終的に判定したいのは、clinicalであるかどうか、だったはずだ。それを、この1つの文がabstractに占める位置付けが「主でない」ということで、clinicalでない、と推定するというのは、意味があるだろうか?


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Last-modified: 2011-01-14 (金) 17:11:47 (2502d)