title: Conditional Survival After Surgical Intervention in Patients With Non-Small Cell Lung Cancer.
abstract: BACKGROUND
  Conditional survival (CS) is defined as living some additional time predicated on living to a certain time point. This study aimed to evaluate the usefulness of CS analyses for postoperative follow-up of surgically treated patients with lung cancer.
  
  
  METHODS
  We retrospectively analyzed survival and clinicopathologic data from 859 patients with non-small cell lung cancer who underwent complete resection. CS is the probability of surviving additional time (y), after an individual has already survived for some time (x), and can be calculated from the following formula: CS(y|x) = S(x + y)/S(x), where S is the overall survival at a specific time.
  
  
  RESULTS
  The 5-year cumulative overall survival rate was 75%. The additional 5-year survival rates at 1, 2, 3, and 4 years after operation (5Y-CS) were 75%, 77%, 77%, and 81%, respectively. The likelihood of surviving for a total of 5 years, 3 years after surgery was 89%. Age less than or equal to 70 years, female sex, no or light smoking, adenocarcinoma histologic type, pathologic stage I, and normal serum carcinoembryonic antigen levels were the clinicopathologic features associated with a high cancer-specific CS. For patients with favorable factors, the 2Y recurrence-free CS (3) reached 100%, whereas 5Y-CS did not change.
  
  
  CONCLUSIONS
  Estimates of CS probabilities may provide more meaningful information than traditional cumulative survival. Even in patients with favorable factors, a postoperative follow-up visit after 3 postsurgical years may be required.
authors.affiliation: Department of Thoracic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan. Electronic address: tfukui@med.nagoya-u.ac.jp.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Fukui
authors.affiliation: Department of Thoracic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Toshiki
authors.initials: T
authors.lastname: Okasaka
authors.affiliation: Department of Thoracic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Kawaguchi
authors.affiliation: Department of Thoracic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Fukumoto
authors.affiliation: Department of Thoracic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Shota
authors.initials: S
authors.lastname: Nakamura
authors.affiliation: Department of Thoracic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Shuhei
authors.initials: S
authors.lastname: Hakiri
authors.affiliation: Department of Thoracic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Ozeki
authors.affiliation: Department of Thoracic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Yokoi
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D012189:Retrospective Studies