Clinical Investigations
High dose rate transperineal interstitial brachytherapy for cervical cancer: high pelvic control and low complication rates

https://doi.org/10.1016/S0360-3016(99)00124-8Get rights and content

Abstract

Purpose: To report the clinical outcome for cervical carcinoma treated with external beam pelvic radiotherapy and interstitial high dose rate (IS-HDR) brachytherapy.

Methods and Materials: Between July 1991 and June 1996, 62 patients with locally advanced stage cervical carcinoma or early stage carcinoma that precluded satisfactory tandem and ovoid insertion were treated. Most patients received 36 Gy (range: 25 Gy–45 Gy) external beam radiotherapy (EBRT) to the pelvis prior to brachytherapy implant. EBRT was continued, with central shielding, to a dose of 50 Gy to the pelvic sidewalls. HDR Iridium-192 brachytherapy was given in 6 fractions of 5.5 to 6.0 Gy. The mean follow-up was 40 months.

Results: Stage distribution was: Stage IB (12), Stage IIA (1), Stage IIB (26), Stage IIIA (6), Stage IIIB (13), and Stage IVA (4). The overall local tumor control was 94%. Local control rates by FIGO stage were Stage I (12/12) 100%, Stage II (25/27) 93%, Stage III (18/19) 95%, and Stage IV (3/4) 75%. The regional pelvic control rates were overall 81%, Stage I (12/12) 100%, Stage II (22/27) 81%, Stage III (15/19) 79%, and Stage IV (1/4) 25%. Distant metastasis developed in 20 patients (32%). The actuarial 5-year disease-free survival was for all patients 48%, Stage I 81%, Stage II 47%, Stage III 39%, and Stage IV O%. Grade 3–4 delayed morbidity resulting from treatment, occurred in 6.5% (4/62) of patients. A fistula without local recurrence occurred in 1.6% (1/62) patients.

Conclusions: We report excellent local and regional pelvic control results using a 6 fraction IS-HDR brachytherapy protocol for cervical carcinoma. The incidence of severe complications is low and suggests that a consistent brachytherapy technique and multiple HDR fractions are therapeutically advantageous to patients treated for cervical carcinoma.

Introduction

The goals of radiation therapy of cervical cancer are eradication of local and regional tumor (in the cervix, parametria and within the pelvis) and avoidance of treatment related morbidity. Conditions that lead to a successful radiation therapy outcome are (i) disease limited to the pelvis, (ii) favorable radiation tumor biology, and (iii) optimal total radiation doses and the creation of a dose differential between normal tissue and tumor. Under certain circumstances, standard intracavitary tandem and ovoid applicators are incongruent with the distribution of the disease. Cases with extensive disease in the cervix, obliteration of the cervical os, narrow fornices, extensions of disease into the lower vagina or infiltrations laterally into the parametria beyond the high dose range of the intracavitary applicators are examples associated with a high incidence of local failure and more complications involving the small bowel, bladder, and rectum.

Two complementary technological advances in radiation therapy address the limitations of standard intracavitary applications; they are interstitial (IS) brachytherapy and high dose rate (HDR) remote afterloading. Interstitial implants provide anatomical access so that the radiation sources can be positioned strategically within and around the cancer. HDR creates optimal dose distributions by precisely controlling source location and dwell time duration. The combination of IS implantation and HDR brachytherapy permits the delivery of a high dosage to the tumor and relatively less dosage to adjacent normal tissues. When HDR brachytherapy is sufficiently fractionated and combined with external beam radiotherapy, there is potential for improved local tumor control and reduction of treatment morbidity.

We present a retrospective analysis of our experience using IS-HDR brachytherapy with previously untreated cervical cancers.

Section snippets

Methods and materials

All patients were examined and staged during the initial consultation and again prior to implantation while under anesthesia. Clinical FIGO staging was by consensus of the brachytherapist and gynecologic oncologist. Additional work-up consisted of cystoscopy, sigmoidoscopy, chest x-ray, abdominal, and pelvic computerized tomography (CT) or magnetic resonance imaging (MRI) scans, complete blood counts, liver and renal chemistries. Biopsy confirmation of invasive carcinoma was obtained in all

Survival

At the conclusion of the study 36 (58%) patients were alive and 34 (55%) were alive with no evidence of disease. The 5-year actuarial survival for all patients was 52% and DFS was 48%. Figure 2 displays the 5-year DFS; Stage I = 81%, Stage II = 47%, Stage III = 39%, and Stage IV = 0%. When the 10 patients who received chemotherapy were excluded from analysis there was no difference in the DFS.

Tumor control

Data on local control, regional control, and distant metastasis for all 62 patients are presented by

Discussion

Brachytherapy is an essential component in the treatment of cervical carcinoma. One of the advantages and the reason for its use is that high doses of radiation are delivered to the tumor in the immediate location of the sources. In addition, with a well-placed implant, the bladder and rectum receive significantly lower doses than the tumor. Fletcher’s three conditions for satisfactory brachytherapy insertions are: (i) The geometry of the radioactive sources must prevent underdosed regions on

Conclusions

We report results and complication rates for carcinoma of the cervix treated with external beam radiotherapy to the pelvis and HDR interstitial brachytherapy. The transperineal template IS implant catheters should fully encompass the tumor and entry into the bladder and rectum should be avoided. HDR technology provides the means to achieve optimal tumor doses and to maintain bladder and rectum doses equal or less than 70–80% of the target. The cases in this study were selected based on having

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    Work performed at California Endocurietherapy Cancer Center, Oakland, California.

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