Table 2.
Time-dependent hazard ratio (95% confidence interval) of all-cause death for smoking after cancer diagnosis for all cancer patients and for current smokers at cancer diagnosis, by cancer sites, The Shanghai Cohort Study 1986–2010
| All patients | Lung Cancer | Stomach Cancer | Colorectal Cancer | Bladder Cancer | Prostate Cancer | Other Cancers | |
|---|---|---|---|---|---|---|---|
| All cancer patients | |||||||
| No. of cases | 1632 | 288 | 362 | 248 | 107 | 132 | 495 |
| No. of deaths (%) | 931(57.0%) | 229 (79.5%) | 159 (43.9%) | 152 (61.3%) | 40 (37.4%) | 47 (35.6%) | 304 (61.4%) |
| Person-years at risk | 6971 | 838 | 1805 | 1077 | 669 | 445 | 2137 |
| Average person-years | 4.3 | 2.9 | 5.0 | 4.3 | 6.3 | 3.4 | 4.3 |
| Average age at diagnosis | 68.8 | 68.1 | 69.6 | 67.9 | 69.2 | 73.3 | 67.9 |
| Median survival time (year) | 5.4 | 2.1 | 10.9 | 4.0 | 15.0 | 8.4 | 5.2 |
| HR (95%CI)-time dependent smoking status* | 1.59 (1.36–1.86) | 1.92 (1.41–2.60) | 1.76 (1.11–2.79) | 1.65 (1.14–2.38) | 3.66 (1.56–8.60) | 1.94 (0.79–4.73) | 1.17 (0.87–1.58) |
| Cancer Patients who were current smokers at cancer diagnosis and survived until the next annual follow-up interview | |||||||
| No. of cases | 747 | 184 | 135 | 114 | 49 | 32 | 233 |
| No. of deaths (%) | 491 (65.7) | 151 (82.1) | 72 (53.3%) | 73 (64.0%) | 23 (46.9%) | 15 (46.9%) | 157 (67.4%) |
| Person-years at risk | 3331 | 547 | 647 | 581 | 311 | 118 | 1126 |
| Average person-years | 4.5 | 3.0 | 4.8 | 5.1 | 6.4 | 3.7 | 4.8 |
| Average age at diagnosis | 67.0 | 66.9 | 69.4 | 65.4 | 67.7 | 70.1 | 65.9 |
| Median survival time (year) for all patients | 4.1 | 2.1 | 7.3 | 4.1 | 12.4 | 6.3 | 4.3 |
| Median survival time (year) for quitters (r=0) | 4.4 | 2.1 | 3.8 | 7.9 | N/A ‡ | 9.8 | 3.3 |
| Median survival time (year) for intermittent smokers (0<r<1.0) | 7.1 | 2.8 | 10.9 | 9.1 | 12.4 | 6.0 | 7.7 |
| Median survival time (year) for continued smokers (r=1) | 2.1 | 1.7 | 3.8 | 2.1 | 2.9 | 11.1 | 2.1 |
| HR (95%CI)-intermittent smokers vs.quitters † | 0.89 (0.70–1.12) | 0.91 (0.59–1.39) | 0.69 (0.38–1.27) | 1.35 (0.68–2.67) | 1.75 (0.28–11.01) | 2.88 (0.22–37.20) | 0.76 (0.49–1.17) |
| HR (95%CI)-continued smokers vs. quitters † | 1.76 (1.37–2.27) | 1.89 (1.18–3.02) | 1.36 (0.70–2.67) | 3.46 (1.69–7.10) | 17.29 (2.25–132.64) | 0.93 (0.08–11.24) | 1.49 (0.92–2.40) |
| HR (95%CI)-time dependent smoking status* | 1.79 (1.49–2.16) | 2.36 (1.63–3.42) | 1.63 (0.98–2.73) | 2.31 (1.40–3.81) | 2.95 (1.09–7.95) | 2.27 (0.40–12.80) | 1.34 (0.96–1.88) |
Derived from a yearly based time-dependent variable of smoking status (yes versus no) after cancer diagnosis with the adjustment for age at diagnosis (continuous), level of education (primary school, middle school, or college or above), cumulative number of pack-year of smoking prior to diagnosis (continuous), and treatment for cancer: surgery (yes/no), chemotherapy (yes/no), and radiation therapy (yes/no). Cox models for all patients were additionally adjusted for cancer site.
All Cox models were adjusted for age at diagnosis (continuous), level of education (primary school, middle school, or college or above), cumulative number of pack-year of smoking prior to diagnosis (continuous), and treatment modalities: surgery (yes/no), chemotherapy (yes/no), and radiation therapy (yes/no). Cox models for all patients were additionally adjusted for cancer site.
Median survival (50% of the patients died) was not reached in this group of bladder cancer patients.