Treatment results of high dose rate brachytherapy in patients with carcinoma of the cervix.

PURPOSE: The combination of external beam irradiation and low-dose-rate brachytherapy is known to be an effective form of treatment in carcinoma of the cervix and any change from this well-established therapeutic combination must be able to equal or improve the treatment results. Since 1984 we have been using high dose rate brachytherapy in conjunction with external beam irradiation for patients with carcinoma of the cervix. This paper reports our long term treatment results in terms of local disease control, survival, and complications. METHODS AND MATERIALS: Between January 1984 and December 1989, 187 previously untreated patients with carcinoma of the cervix underwent combined external beam irradiation and high dose rate brachytherapy. The International Federation of Gynecology and Obstetrics stage distribution of patients was as follows: I B = 15, II A = 35, II B = 68, III A = 9, III B = 54, IV A = 6. External beam irradiation to the whole pelvis was delivered by megavoltage irradiation with once-a-day fractionation, to a median dose 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 time 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. One 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 weeks of radiation therapy, or following its completion. Maximum rectal and 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 patients at risk, 23 patients developed 25 complications attributable to radiotherapy (13 rectal, 3 bladder, 8 small bowel, 1 fistula) at a median time of 18 months following completion of treatment. Thirteen complications (7.6%) were grades 3 or 4. Patients with Stage II disease had a higher incidence of complications than patients with Stages I and III disease (p < 0.05). Rectal complications were significantly higher in patients who received a total rectal dose > 5400 cGy (p = 0.045). CONCLUSION: High-dose-rate brachytherapy treatment results are comparable to those obtained with low dose rate brachytherapy techniques. The use of three high dose rate brachytherapy insertions is a practical, economical, and safe treatment for patients with carcinoma of the cervix.

Colposcopic evaluation of abnormal Papanicolaou smears in pregnancy.

Colposcopy was used to examine 401 pregnant patients with cytologic or clinical abnormalities of the cervix to determine if routine biopsy could be safely omitted except where the colposcopic impression was one of possible invasive carcinoma. A comparison of the antepartum colposcopic impressions with the postpartum histologic diagnosis revealed agreement to within one degree in 87% of patients, with 3% of patients showing a more advanced lesion than that anticipated. Only 2% of patients showed a progression of cytologic abnormalities at postpartum examination; 39% showed marked improvement. Four of nine patients with invasive carcinoma were diagnosed at antepartum colposcopy, with an additional two patients recognized as having invasive cancer at the postpartum colposcopic examination. The omission of routine biopsy is less than ideal if only one antepartum colposcopy is performed, since a considerable period of time may elapse before the patient is seen again postpartum. Those situations in which it may be omitted, together with guidelines for the management of pregnant patients with abnormal cervical cytologic findings, are presented.

Fetal oxygen extraction: comparison of the human and sheep.

To estimate fetal oxygen extraction in the human, the inverse, linear relationship between umbilical arterial PO2 and oxygen extraction was calculated from measurements made on cord blood samples obtained after vaginal (n = 12) and cesarean (n = 16) delivery and used to predict oxygen extraction in utero. Comparisons with similar data from fetal lambs in utero and during labor and delivery indicate that extraction in the human and sheep fetus is 47% and 27%, respectively, at PaO2 = 20 mm Hg. For the human fetus to have extraction similar to that in the fetal lamb, vascular PO2 would have to be substantially higher. This would lead to a higher umbilical venous oxygen content in the human, compensating for the lower umbilical blood flow and yielding a rate of oxygen delivery comparable with that observed in the fetal sheep. These data indicate that there may be significant quantitative differences in the fetal oxygen delivery systems in the human and sheep.