man was lost as a result of surgery for each man "cured." Dr. Beattie made the assumption that the average survival of men treated by pneumonectomy is 15 months and calculated that the 36 men who died postoperatively lost 432 months of life (should this not be 36 X 15 = 540?) but this loss was overwhelmingly offset by a gain of 2,100 months among the 35 who survived five years ( 35 X 60) . Dr. Beattie correctly stated that "the unknown factor here would be the survival time or 'cure' of the pneumonectomy group if not operated . upon." This unknown factor cannot be ignored. As I pointed out in my discussion, the assessment of time lost and gained as a result of surgery requires a controlled study in which patients suitable for pneumonectomy are randomized between surgery and no treatment. Let us make some calculations from the data that might be obtained from such a controlled study. Patients who are suitable for pneumonectomy have more favorable disease than those who are not. Dr. Beattie set the average survival of patients who are explored but found to have unresectable cancers at nine months and the average survival of those who have pneumonectomies at 15 months. Let us assume that the average survival of unoperated candidates for pneumonectomy is 12 months. In the absence of surgery 212 patients would survive a total of 2,544 months ( 212 X 12). The same 212 patients subjected to pneumonectomy would survive a total of 3,180 months ( 212 X 15), or an additional 636 months. However, the additional 636 months are offset by a surgical loss of 540 months ( 36 X 15) . Therefore, the net gain for 212 major operations would be only 96 months (about two weeks per patient), a rather paJtry reward for a lot of effort and pain. In the case of right pneumonectomy over the age of 60, there were 47 patients with 14 operative deaths and only eight five-year survivors in my report. Dr. Beattie's calculations showed that 210 months were lost but 480 months were gained. My calculations using a hypothetical control group show that only 141 months would be gained over the survival expected without operation and therefore right pneumonectomy really results in a net loss of 69 months ( 210 - 141) or about 1.5 months per patient. Actually, the average is not an appropriate parameter for comparison of survival data because the distribution of survival times is skewed markedly. The median would be a better measure of central tendency. However, this is a small matter. What is more important is to recognize that unless a controlled study is mounted, the value of pneuCHEST, 68: 3, SEPTEMBER, 1975

monectomy cannot be assessed and calculations based on assumptions of uncertain validity are not a satisfactory substitute for controlled investigation. William Weiss, M.D. Professor of Medicine Hahnemann Medical College Philadelphia REFERENCES

Weiss W: Operative mortality and five-year survival rates in men with bronchogenic carcinoma. Chest 66:483-487, 1974 2 Beattie EJ Jr: Operative mortality and five-year survival rates in men with bronchogenic carcinoma. Chest 66: 469, 1974

More on Survival Rates for Bronchogenic Carcinoma Patients To the Editor: I would take exception to some of the implications of the article by William Weiss, M.D., entitled "Operative Mortality and Five-Year Survival Rates in Men with Bronchogenic Carcinoma" (Chest 66:483487, 1974) . Comparing an operative death rate in his patients to a five-year survival rate as an indication for surgery, and using this as a reason to tum down surgery on patients who are elderly, does not make good clinical sense. In the Northwest an operative mortality rate of 18.3 percent would result in a whole-scale reevaluation of the quality of the surgical procedures that were being performed. I realize this is a 30-day operative mortality rate, but in general, patients who are that ill with carcinoma, if they are unlikely to survive for 30 days after a surgical procedure, are those who probably could have, by modem techniques, been determined to be inoperable and nonresectable prior to surgery. In addition, in Dr. Weiss' Table 7, his operative mortality for pneumonectomy of 17 percent and lobectomy of 10 percent is exceedingly high by my standards, and casts a bias upon the article which makes it impossible to obtain any meaningful information from it. Alan C. Whitehouse, M.D. Spokane

To the Editor: Dr. Whitehouse justifiably criticizes the operative death rates I reported as being too high. I agree with him. Indeed, this is one of the reasons I wrote the COMMUNICATIONS TO THE EDITOR 391