TREATMENT RESULTS OF HIGH-DOSE-RATE BRACHYTHERAPY IN PATIENTS WITH CARCINOMA OF THE CERVIX

Purpose: The combination of external beam irradiation and low-dose-rat e brachytherapy is known to be an effective form of treatment in carci noma of the cervix and any change from this well-established therapeut ic combination must be able to equal or improve the treatment results. Since 1984 we have been using high dose rate brachytherapy in conjunc tion with external beam irradiation for patients with carcinoma of the cervix. This paper reports our long term treatment results in terms o f local disease control, survival, and complications. Methods and Mate rials: Between January 1984 and December 1989, 187 previously untreate d patients with carcinoma of the cervix underwent combined external be am irradiation and high dose rate brachytherapy. The International Fed eration of Gynecology and Obstetrics stage distribution of patients wa s as follows: I B = 15, II A = 35, II B = 68, III A = 9, III B = 54, I V A = 6. External beam irradiation to the whole pelvis was delivered b y megavoltage irradiation with once-a-day fractionation, to a median d ose of 4600 cGy. High dose rate brachytherapy was delivered by a high- dose-rate remote controlled afterloading unit, containing 20 spherical Cobalt 60 sources with a nominal activity of 19 GBq (0.5 Ci) at the t ime of installation, giving a typical dose rate to point A of 160 cGy/ min, decreasing to about 80 cGy/min at the end of the 5-year study. On e to 3 high dose rate brachytherapy treatments delivering 800 to 1000 cGy to point A were given weekly concurrently with the last 2 to 3 wee ks of radiation therapy, or following its completion. Maximum rectal a nd bladder doses were routinely measured for each treatment. Results: Overall 5-year actuarial survivals were as follows: I B = 72%, II A = 65%, II B = 66%, III A = 66%, III B = 45%. Five-year actuarial pelvic control rates were as follows: I B = 66%, II A = 83%, II B = 78%, III A = 88%, III B = 40%. At a median follow-up time of 54 months for pati ents at risk, 23 patients developed 25 complications attributable to r adiotherapy (13 rectal, 3 bladder, 8 small bowel, 1 fistula) at a medi an time of 18 months following completion of treatment. Thirteen compl ications (7.6%) were grades 3 or 4. Patients with Stage II disease had a higher incidence of complications than patients with Stages I and I II disease (p < 0.05). Rectal complications were significantly higher in patients who received a total rectal dose > 5400 cGy (p = 0.045). C onclusion: High-dose-rate brachytherapy treatment results are comparab le to those obtained with low dose rate brachytherapy techniques. The use of three high dose rate brachytherapy insertions is a practical, e conomical, and safe treatment for patients with carcinoma of the cervi x.