Correspondence

Smoking and Radiation Therapy for Head and Neck Cancer

N Engl J Med 1993; 328:1784-1785June 17, 1993

Article

To the Editor:

In their study of cigarette smoking during radiation therapy in patients with head and neck cancer Browman et al. (Jan. 21 issue)1 did not provide any details about their patients' smoking behavior during radiation therapy or their subsequent clinical course. The authors should have mentioned the number of cigarettes smoked during therapy instead of grouping all smokers together regardless of how many or how few cigarettes were smoked. A quantitative analysis might have provided some clues to the mechanism of the interaction between smoking and radiation therapy.

The authors also did not discuss the patients' smoking behavior after therapy, when in all likelihood, some patients who smoked during treatment quit smoking and some who did not smoke during treatment resumed smoking. The authors therefore cannot tell us what effect smoking after radiation therapy may have had on tumor control and survival. This effect could have been much greater than the effect produced by smoking or not smoking during the 6 1/2 weeks of radiation therapy.

Of additional importance is the lack of information about the further treatment of the patients. A substantial number of patients with cancer of the larynx and oral cavity who have local recurrences of tumor or in whom the tumor persists after initial radiation therapy benefit from surgery2-4. Since the difference in the number of deaths caused by cancer between the smokers and nonsmokers in this study was only 6 (31 vs. 25 deaths), the difference in the rates of ultimate control of the tumor was far less impressive than the difference in the rates of initial complete response in the two groups (45 percent vs. 74 percent). These results indicate that smoking during radiation therapy may have had less of an effect on ultimate tumor control, and hence survival, than did the patients' post-radiation treatment.

Harry R. Katz, M.D.
Chesapeake Regional Cancer Center, Mechanicsville, MD 20659

4 References

1. 1

   Browman GP, Wong G, Hodson I, et al. Influence of cigarette smoking on the efficacy of radiation therapy in head and neck cancer. N Engl J Med 1993;328:159-163
   Full Text | Web of Science | Medline

2. 2

   Fletcher GH. Textbook of radiotherapy. 3rd ed. Philadelphia: Lea & Febiger, 1980.
   

3. 3

   Perez CA, Brady LW, eds. Principles and practice of radiation oncology. Philadelphia: J.B. Lippincott, 1987.
   

4. 4

   DeVita VT Jr, Hellman S, Rosenberg SA, eds. Cancer: principles and practice of oncology. 3rd ed. Philadelphia: J.B. Lippincott, 1989.
   

Author/Editor Response

The authors reply:

To the Editor: We agree that evidence of a dose-gradient relation would strengthen the causal inference of the association between the level of smoking during radiation therapy and clinical outcome, but we do not have sufficient information in the cohort of smokers to examine dose-gradient effects. We also do not have information on smoking behavior after radiation therapy. In another study, there was an effect of smoking behavior after diagnosis on survival in patients with head and neck cancer, but the difference in survival did not emerge until one year of follow-up had been completed.1 We concluded that smoking during radiation therapy was an important variable contributing to survival in our study because of the marked difference in the response to radiation therapy between smokers and nonsmokers, a factor that is less likely to be influenced by post-treatment smoking behavior. To determine whether the difference in survival between smokers and nonsmokers was more likely to be related to smoking during radiation therapy than to smoking after radiation therapy, we examined the relation between the response to treatment and survival and the disease-free survival among smokers and nonsmokers in our study. The difference in survival between patients who responded to radiation therapy and those who did not was statistically significant (P<0.001); 82 percent of the former and 23 percent of the latter were alive two years after treatment. The disease-free survival among the patients who responded to radiation therapy, which is more likely to be influenced by smoking behavior after treatment, was the same among smokers and nonsmokers. Eighteen of 53 smokers (34 percent) and 13 of 62 nonsmokers (21 percent) underwent surgery at some time after radiation therapy.

We are continuing to evaluate other potential confounding variables, including the extent of smoking before radiation therapy, which was significant in our regression analysis. However, until alternative explanations or contradictory evidence is produced, we believe it is reasonable to use our results to encourage patients with head and neck cancer not to smoke during radiation therapy.

George P. Browman, M.D.
McMaster University, Hamilton, ON L8N 3Z5, Canada

Gene Wong, M.D.
University of New Mexico, Albuquerque, NM 87131

D. Ian Hodson, M.D.
Mark N. Levine, M.D.
McMaster University, Hamilton, ON L8N 3Z5, Canada

1 References

1. 1

   Stevens MH, Gardner JW, Parkin JL, Johnson LP. Head and neck cancer survival and life-style change. Arch Otolaryngol 1983;109:746-749
   Web of Science | Medline

Citing Articles (2)

Citing Articles

1. 1

   Michael B. Steinberg, Jennifer Randall, Shelley Greenhaus, Amy C. Schmelzer, Donna L. Richardson, Jeffrey L. Carson. (2011) Tobacco dependence treatment for hospitalized smokers: A randomized, controlled, pilot trial using varenicline. Addictive Behaviors 36:12, 1127-1132
   CrossRef

2. 2

   François Meyer, Isabelle Bairati, André Fortin, Michel Gélinas, Abdenour Nabid, François Brochet, Bernard Têtu. (2008) Interaction between antioxidant vitamin supplementation and cigarette smoking during radiation therapy in relation to long-term effects on recurrence and mortality: A randomized trial among head and neck cancer patients. International Journal of Cancer 122:7, 1679-1683
   CrossRef