brachytherapy in carcinom of the uterine cervix - NCBI

INDICATION FOR INTERSTITIAL BRACHYTHERAPY IN CARCINOM OF THE UTERINE CERVIX P. Pradeep Kumar, MD, Judith Taylor, MD, Joseph C. Scott, Jr, MD, Allan J. Jacobs, MD, and John Rojas, MD Omaha, Nebraska

More than 40 patients with gynecological, genitourinary, and gastrointestinal malignancies, both primary and recurrent but confined to the pelvis, were treated with interstitial irradiation over a four-year period. Interstitial irradiation was the choice of treatment for early carcinoma of the prostate, carcinoma of the anal canal less than T2, recurrent carcinoma of the uterine cervix, and carcinoma of the cervical stump. The authors' experience in treating recurrent carcinoma of the uterine cervix with interstitial irradiation is the basis for the indications for selecting the technique of interstitial irradiation presented.

A proper combination of supervoltage external beam radiation and afterloading intracavitary

From the Division of Radiation Oncology and the Department of Obstetrics and Gynecology, University of Nebraska Medical Center, Omaha, Nebraska. Requests for reprints should be addressed to Dr. P. Pradeep Kumar, Division of Radiation Oncology, University of Nebraska Medical Center, 42nd and Dewey Avenue, Omaha, NE 68105.

radiation is the most effective, safe, and widely used method of treating at least stage I and stage II carcinoma of the uterine cervix." 2 Even in advanced stages, such as stage III, good initial tumor control can be achieved with judicious use of both external and intracavitary irradiation, even though there is a place for interstitial irradiation in the initial treatment of stage III disease. The use of interstitial irradiation in the treatment of carcinoma of the uterine cervix, however, should be limited to the management of pelvic recurrences following primary radiotherapy, surgery, or both, and for primary tumors arising from the cervical stump where intracavitary radiation cannot be used. Pelvic recurrence following radiation or surgery for carcinoma of the uterine cervix is not infrequent, especially in advanced stages.3'4 Salvage of these previously treated patients with either radical surgery or radiation (either external or interstitial using 226Ra or 222Rn) usually carries a high risk of morbidity and mortality and produces a low yield of tumor control.57 With the availability of isocentric supervoltage radiotherapy machines and low-energy, short-half-life radioactive isotopes such as.'92Ir and 1251 and new implant techniques to use these isotopes, retreatment.of pelvic

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BRACHYTHERAPY IN CERVICAL CANCER

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Figure 1. Carcinoma of the cervical stump with no parametrial extension

Figure 2. Left side wall recurrence seven years after radical hysterectomy for stage I carcinoma of the cervix

recurrences is more feasible and less morbid.8 However, it is important to establish proper indications for the selection of various retreatment techniques. Two factors are important in this selection process: (1) prior treatment method, and (2) site of pelvic recurrence. The purpose of this paper is to outline the indications for selection of interstitial irradiation technique in the treatment of carcinoma of the uterine cervix.

Figure 3. Central recurrence extending to left side wall

MATERIALS AND METHODS Between March 1979 and March 1983 a total of 44 patients with both primary and recurrent pelvic malignancies were treated with interstitial irradiation at the University of Nebraska Medical Center. The authors used interstitial irradiation to treat recurrent carcinoma of the uterine cervix and carcinoma of the cervical stump, where intracavitary irradiation cannot be performed. The authors' experience led to the classification of the site of the pelvic recurrence into four distinct groups on the basis of CT findings for the selection of interstitial implant technique. For all practical purposes, the site of pelvic recurrence was classified as central recurrence (Figure 1); pelvic side wall recurrence confined to the true pelvis (Figure 2); 722

central recurrence extending to the pelvic side wall or vice versa (Figure 3); or recurrent disease outside the true pelvis, but confined to the false pelvis, usually along the external or common iliac vessels (Figure 4 A and B). Central recurrences following primary surgical treatment and primary cervical stump carcinomas that are not amenable to surgery are managed in a similar way. The tumor is treated initially with supervoltage external radiation to a tumor dose



Figure 4. (A) Recurrence along the left external iliac vessels six years after radiation therapy for stage I carcinoma of the cervix. (B) Recurrence along the right common iliac vessels five years after radiation therapy for stage I carcinoma of the cervix

(TD) of 4,000 to 5,000 rad or 40 to 50 Gy to shrink the lesion as much as possible so that the residual central disease can be encompassed with transperineal removable afterloading interstitial implant9 (Figure 5). With interstitial implant, an additional 4,000 to 5,000 rad or 40 to 50 Gy TD is delivered in two sittings at a minimum interval of two weeks. Complete response is achieved in 70 percent of cases (Figure 6). Central lesions more than 6 cm in lateral dimension are difficult to cover completely with the transperineal template technique because of the pubic arch. Needles in the third circle and beyond of the template converge as they are pushed into the tumor. This leads to a high dose rate, a short treatment time, and a higher complication rate. In such instances, the lateral extension of the central disease that cannot be encompassed by the transperineal removable implant should be treated separately either with transperineal 1251 permanent implant or with localized external boost using special techniques, such as the arc technique. Central recurrences following primary irradiation not amenable to surgical salvage should be meticulously managed with fractionated transperineal removable afterloading interstitial irradiation. Pelvic side wall recurrence following primary surgery is treated initially with supervoltage external radiation to a TD of 5,000 to 6,000 rad or 50 to 60 Gy to shrink the lesion as much as possible

Figure 5. Transperineal removable afterloading implant used for central recurrences and carcinoma of the cervical stump

(Figure 7). The boost dose to residual disease in this location is best achieved by transperineal 1251 permanent implant under "C" arm control. In this technique, the limitation by the pubic arch in reaching the lateral pelvic wall is overcome by placing the transperineal needles obliquely (Figures 8 and 9), which cannot be done in transperineal removable afterloading implant techniques. These lateral lesions cannot be exposed satisfactorily through celiotomy following external


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Figure 6. Complete response of the tumor shown in Figure 1 following external radiation therapy and removable interstitial implant

Figure 8. The residual tumor in Figure 7 being implanted transperineally with 1251 seeds as seen on an image-intensifying screen of the "C" arm. Bladder is filled with contrast

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Figure 7. Sixty percent regression of the tumor shown in Figure 2 following external radiation therapy

radiation therapy for suprapubic I25I permanent implant. A similar approach should be used in treating pelvic side wall recurrences following primary radiation. However, additional external radiation prior to 1251 permanent implant should be given cautiously or not at all depending on the previous radiation dose. Recurrences outside the true pelvis but below the bifurcation of the abdominal aorta are not amenable to transperineal implant techniques, whether removable or permanent. These lesions should be exposed extraperitoneally, if possible, 724

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Figure 9.1251 seeds in the tumor along the left pelvic wall following transperineal implant

for possible resection, permanent 1251 implant, or both. External radiation, if needed, should be given only after the surgical procedure, but not before, because the exposure, resection, or 1251



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Figure 10.1251 seeds in suture supplied in metal ring by 3M Company being used to implant the tumor along the common iliac vessels shown in Figure 4

implant becomes difficult following external radiation. These lesions, which are usually along the common and external iliac vessels, can best be implanted suturing 1251 seeds in sutures supplied by 3M (Figure 10) rather than using straight needles and an implant gun, which carries the risk of puncturing major vessels close to the tumor.

DISCUSSION Supervoltage isocentric external irradiation and intracavitary afterloading brachytherapy are effective in the primary management of most of the carcinomas of the uterine cervix and can be easily performed. With the availability of radioisotopes such as 192Ir and 1251, and various techniques to use them, interstitial irradiation of pelvic recurrences at various sites following primary treatment for carcinoma of the uterine cervix can be very effectively done with minimum morbidity and mortality. However, it is important to establish precisely the site of pelvic recurrence with a meticulous pelvic examination and CT scan and select the proper technique to accomplish accurate placement of the implant in the tumor volume to

achieve maximum tumor control with minimum morbidity and mortality. Supervoltage external radiation prior to interstitial implant should be used whenever possible to achieve tumor regression so that compact implants can be performed. Interstitial irradiation with direct implantation of 226fRa or 222Rn should not be used in the retreatment of pelvic recurrences because of the possibility of inaccurate placement of the needles or seeds and their high gamma energy, both of which lead to high complication rate with poor tumor control. The use of interstitial irradiation in the initial management of locally advanced carcinoma of the cervix should be reconsidered because of the high complication and local failure rates associated with this technique.10

Literature Cited 1. Fletcher GH. Textbook of Radiotherapy, ed 3. Philadelphia: Lea & Febiger, 1980, pp 720-789. 2. Kumar PP. Stable and comfortable afterloading cervix applicator. Acta Radiol Oncol 1981; 20:61-63. 3. Jampolis S, Andras EJ, Fletcher GH. Analysis of sites and causes of failures of irradiation in invasive squamous cell carcinoma of the intact uterine cervix. Radiology 1975; 115: 681-685. 4. Kottmeir HL. Evaluation of treatment of recurrence after surgery and radiotherapy for carcinoma of the cervix. In: Cancer of the Uterus and Ovary. Chicago: Year Book Medical, 1969, pp 283-294. 5. Brunschwig A. Some reflections on pelvic exenterations after twenty years experience. In: Sturgis SH, Taymos ML, eds. Progress in Gynecology, vol 5. New York: Grune & Stratton, 1970. 6. Evans SR Jr, Hilaris BS, Barber HRK. External versus interstitial irradiation in unresectable recurrent cancer of the cervix. Cancer 1971; 28(5):1284-1288. 7. Murphy WT, Schmitz A. Results of re-irradiation in cancer of cervix. Radiology 1956; 67:378-385. 8. Puthawala AA, Syed AMN, et al. Re-irradiation with interstitial implant for recurrent pelvic malignancies. Cancer 1982; 50:2810-2814. 9. Syed AMN, Feder BH. Technique of after-loading interstitial implants. Radiol Clin North Am 1977; 46:458-475. 10. Ampuero F, Doss LL, Khan M, et al. The SyedNeblett interstitial template in locally advanced gynecological malignancies. Int J Radiat Oncology Biol Phys 1983; 9:1897-1903.

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