Carbogen inhalation in cervical cancer: Assessment of oxygenation change

Objective. Our objectives were (1) to examine tumor oxygenation measured wi th an Eppendorf pO(2) histograph, prior to and during carbogen (95% oxygen, 5% carbon dioxide) breathing in patients with primary cervical cancer; and (2) to assess the feasibility of delivering external beam radiation therap y and concurrent carbogen to patients treated for cervical cancer. Methods. Pretreatment tumoral pO(2) measurements were obtained using an Epp endorf pO(2) histograph in patients with primary cervical cancers while bre athing room air and after 4 min of carbogen breathing, Patients able to tol erate the carbogen inhalation were asked to inhale it for 4 min prior to an d during all external beam radiation therapy. Results. Two sets of pO(2) measurements were obtained from 25 patients. The average median pO(2) increased from 8 mm Hg when breathing room air to 96 mm Hg after carbogen breathing. Twenty-four of 25 patients tolerated the ca rbogen; they inhaled carbogen during their daily external beam radiation th erapy. All 24 patients completed their planned course of external beam radi ation therapy and daily concurrent carbogen without significant difficulty. Conclusion. (1) Carbogen inhalation increased the average median pO(2) valu e 10-fold and decreased the percentage of values less than or equal to 2.5 and 5 mm Hg. (2) Carbogen inhalation is feasible during external beam pelvi c radiation. (C) 1999 Academic Press.