Poster Presentation COSA 2015 ASM

Smoking and the influence of behavioural factors in the outcomes of patients with colon cancer (#192)

Rachel Delahunty 1 , Julie Johns 2 , Michael Harold 2 , Peter Gibbs 1 2
  1. Oncology, Western Health, Melbourne, Victoria, Australia
  2. Oncology, Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia

Purpose

Smoking is an established risk factor for colorectal cancer (CRC). The molecular profile of CRC in smokers may be different to non-smokers, which might contribute to the reported detrimental effects on disease free (DFS) and overall survival (OS). Not fully explored is differences in behaviour between smokers and non-smokers that might also affect outcomes.  

Patients and Methods

Using prospectively collected multidisciplinary data 2003-2014 from 3 Melbourne hospitals. Smoking history, demographics, diagnosis, treatment and outcomes were examined. Our focus was on patients ≤ 70 years old(yo) (due to the confounding of age) with early stage colon cancer; comparing current smokers with never-smokers.

Results

2521/ 4655 patients on the database had early stage colon cancer, 511 (20.3%) stage 1, 1120 (44.4%) stage 2 and 890 (35.3%) stage 3. 280 (11.1%) were current smokers, 769(30.5%) ex-smokers and 1472 (58.4%) never smokers.  Compared to never smokers, current smokers were younger (median age 62.73 vs 70.57, p=<.0001), predominately male (63.21% vs 42.32%, p=<0.001),with lower BMI (25.6% vs 26.7%, p=0.00014) and were more socially disadvantaged (IRSAD 997 vs 1022, p = <.0001).  For patients ≤ 70 yo the rate of screen detected cancers (14.6% vs 21.4%), stage at presentation (stage I, II, III 19.1,44.3,36.3% vs 19.5, 40.7,39.8%) and acceptance of adjuvant chemotherapy for stage III disease were 48.1 vs 50.8%. Adjuvant therapy completion rates were similar (34.4 vs 37.4). For patients ≤70 yo stages I-III combined, distant DFS was 83 vs 80% at 5 years, (HR 0.888, p = 0.5395) and OS 87 vs 86% at 5 years(HR 1.193, p = 0.0468 . Death without recurrence occurred in 22/42 (52%) vs 98/209 (47%). 

Conclusion

Smokers are less likely to have screen detected CRC, but accept and complete adjuvant therapy at similar rates to non-smokers. There is no impact of smoking on disease specific survival, with the excess of deaths in smokers due to non-CRC cancer deaths.