The Effect of Smoking on Side Effects Among Cancer Patients Throughout Treatment: a URCC CCOP Study of 947 Patients

Background: Cigarette smoking during cancer treatment adversely affects overall survival, disease-free survival, and disease recurrence. Very few studies investigated the effect of smoking on cancer-related side effects, but smoking in cancer patients represents an important problem because it may exacerbate side effects, which could lead to treatment interruptions and compromised treatment efficacy.

Purpose: To examine the influence of cigarette smoking on side effects among 947 cancer patients throughout treatment.

Methods: Patients diagnosed with cancer and scheduled to receive chemotherapy and/or radiation therapy reported on current smoking status (yes, no) and the severity (on an 11-point scale ranging from 0 gNot Presenth to 10 = “As Bad as You Can Imagineh) of 12 side effects (fatigue, hair loss, memory, nausea, depression, sleep, pain, concentration, hot flashes, weight loss, skin problems, and shortness of breath) at pre-treatment, during treatment, and 6-month follow-up. The total mean of the aforementioned side-effects was determined for self-reported smokers (S) and non-smokers (NS) using ANCOVA controlling for sociodemographic variables, treatment, cancer site, and Karnofsky score.

Results: S were more likely to be non-Caucasian, younger, single, and less educated (all P < 0.05) than NS. S reported a higher total mean side effect severity than NS prior to treatment (S = 1.73 vs. NS = 1.47; P = 0.02), during treatment (S = 3.91 vs. NS = 3.43; P = 0.03), and at 6-month follow-up (S = 2.34 vs. NS = 1.80; P < 0.01). S also reported a greater increase in total mean side effect severity from pre-treatment to treatment (S = +2.48 vs. NS = +2.05; P = 0.04). S who quit smoking (Q) between baseline and 6-month follow-up reported lower total mean side effect severity than S who continued to smoke at 6-month follow-up (Q = 1.36 vs. S = 2.34; P = 0.04).

Conclusion: S reported greater side effect severity compared to NS prior to treatment, during treatment, and at 6-month follow-up. S also experienced a greater increase in side effect severity than NS from pre-treatment to treatment. S who quit reported lower side effect severity than S who continued smoking. Targeted cessation efforts for S to decrease side effect severity may limit the likelihood of treatment interruptions.