Radiation therapy morbidity in carcinoma of the uterine cervix: dosimetric and clinical correlation

A pre-optimised dosimetry system using a rigid applicator for intracavitary treatment of cervical carcinoma

AIMS

Tumour control and complication risk have been major concerns in the treatment of cervical carcinoma. A review of dose distribution for intracavitary treatment of cervical carcinoma revealed that modification of the Manchester dosimetry system is necessary for cases of narrow-sized vagina. A revised dosimetry system was introduced in the present study, with the objective of optimising the dose coverage for the parametrium while minimising the bladder and rectum dosage by restricting the rectal dose so as not to exceed 75% of the brachytherapy prescription dose.

MATERIALS AND METHODS

A suitable-sized applicator was selected according to the patient's anatomy. The revised system is optimised based on the fixed geometry of the applicator. The system was therefore predefined and the distribution of the treatment dose already determined before application. The revised system was applied to 135 cases, involving 540 applications. The clinical outcome in terms of local tumour control and complication rates is reported. The differences between the revised system and the Manchester system in terms of dose coverage for the parametrium and the rectum dose were compared.

RESULTS

The results showed that higher rectal and parametrial dosages were obtained with the Manchester system as compared with the revised system. Our study showed that over 50% of our patients would have received a rectal dose close to 100% of the point A dose if the Manchester system was applied, whereas it was restricted to below 75% using the revised system. Using the revised system, the significance of the parametrial dosage coverage in relation to local control was assessed: the mean dose to the rectum and the bladder as a percentage of point A was 65.7 +/- 5% (range 50-85%) and 66.4 +/- 14% (range 29-116%), respectively. The 5-year actuarial local failure-free survival rates were 90, 92.9, 86.8, 100, 69.7 and 0% for stages IB, IIA, IIB, IIIA, IIIB and IV (P < 0.0001), respectively. The 3-year actuarial complication rates (grade 3/4) for proctitis and cystitis were 1.4 and 0.5%, respectively. The dosage coverage for the parametrium was found to be significant (P = 0.029) in relation to local control for early-stage disease.

CONCLUSIONS

The favourable local tumour control and low complication rates shown by our results indicate that the revised system presents an optimal dose distribution, particularly for the application of small ovoids, whereas morbidity was reduced to a lower level without compromising local control.

Comparative assessment of doses to tumor, rectum, and bladder as evaluated by orthogonal radiographs vs. computer enhanced computed tomography-based intracavitary brachytherapy in cervical cancer

PURPOSE

To carry out a comparative assessment of intracavitary brachytherapy (ICBT) doses to tumor, bladder, and rectum based on orthogonal films and contrast enhanced computed tomography (CECT).

METHODS AND MATERIALS

Fifty-five ICBT procedures with CT/MRI compatible applicator and CECT scans were evaluated. Doses to Point A, International Commission on Radiation Units and Measurement (ICRU) reference points for maximum bladder (B max(ICRU)) and rectum (R max(ICRU)) localized from orthogonal films were compared with CECT delineated tumor, bladder (B max(CECT)), and rectum (R max(CECT)) doses, respectively. The 95th and 90th percentile bladder (B 95(CECT) and B 90(CECT)) and rectal (R 95(CECT) and R 90(CECT)) doses based on CECT were also estimated.

RESULTS

Mean percentage tumor volume encompassed within the prescribed dose of 600 cGy to Point A was 88.8%. Mean B max(ICRU), B max(CECT), R max(ICRU), and R max(CECT) were 631.3 cGy, 1221.4 cGy, 454.8 cGy, and 526.9 cGy, respectively. Paired mean differences were significant between B max(ICRU) and B max(CECT) or B 95(CECT) (both p < 0.001); R max(ICRU) and R max(CECT) (p = 0.005) or R 90(CECT) (p < 0.001), whereas insignificant for B max(ICRU) and B 90(CECT) (p = 0.281), and R max(ICRU) and R 95(CECT) (p = 0.372).

CONCLUSIONS

Prescription based on Point A ICBT doses could lead to uncertainty and underdosage in tumor. ICRU 38 maximum bladder and rectal doses significantly underestimate the maximum doses to these organs and represent the 90th and 95th percentile of the maximum doses to these organs, respectively.

Small bowel perforation without tumor recurrence after radiotherapy for cervical carcinoma: report of seven cases

AIM

We describe the clinical presentation, evaluation, management and outcome of patients experiencing small bowel perforation following radiation therapy for cervical cancer.

METHODS AND MATERIALS

A database consisting of 95 Japanese women with stage 0-4 A cervix cancer treated between 1991 and 2004 contained seven patients (7.4%) with small bowel perforation.

RESULTS

The median age at the time of perforation was 72.5 years (range 62-78). The median time from completion of radiotherapy to perforation was 6 months (range 2-58). Surgery (one small bowel resection and anastomosis with diversion; six small bowel resection and anastomosis) was performed immediately in all seven patients. One of seven patients died of small bowel perforation (i.e. mortality rate was 14%). Bowel adhesion was detected during the operation in only three cases (43%). Signs of peritonitis were absent in six cases (86%). Severe abdominal pain was seen in all seven patients. The perforation site was ileum in all seven cases. In all patients, pathological changes were compatible with postirradiation injury of the gastrointestinal tract.

CONCLUSIONS

The presenting complaints of patients with bowel perforation following radiotherapy vary, and signs of peritonitis may be absent. Emergency physicians must be alert for these complications in patients who have been treated with radiotherapy.

Bladder filling variation during radiation treatment of prostate cancer: Can the use of a bladder ultrasound scanner and biofeedback optimize bladder filling?

PURPOSE

To investigate the use of a bladder ultrasound scanner in achieving a better reproducible bladder filling during irradiation of pelvic tumors, specifically prostate cancer.

METHODS AND MATERIALS

First, the accuracy of the bladder ultrasound scanner relative to computed tomography was validated in a group of 26 patients. Next, daily bladder volume variation was evaluated in a group of 18 patients. Another 16 patients participated in a biofeedback protocol, aiming at a more constant bladder volume. The last objective was to study correlations between prostate motion and bladder filling, by using electronic portal imaging device data on implanted gold markers.

RESULTS

A strong correlation between bladder scanner volume and computed tomography volume (r = 0.95) was found. Daily bladder volume variation was very high (1 SD = 47.2%). Bladder filling and daily variation did not significantly differ between the control and the feedback group (47.2% and 40.1%, respectively). Furthermore, no linear correlations between bladder volume variation and prostate motion were found.

CONCLUSIONS

This study shows large variations in daily bladder volume. The use of a biofeedback protocol yields little reduction in bladder volume variation. Even so, the bladder scanner is an easy to use and accurate tool to register these variations.

Evaluation of Late Toxicities of Patients with Carcinoma of the Cervix Treated with Radical Radiotherapy: An Audit from India

AIMS

To evaluate the incidence of, and factors affecting, late toxicities of women with carcinoma of the cervix treated with radical radiotherapy.

MATERIALS AND METHODS

Between 1996 and 2001, 1069 women with carcinoma of the cervix (stage I-IVA) were treated at our centre with external-beam radiotherapy (EBRT) and intra-cavitary radiotherapy (ICRT) (n = 871) or EBRT alone (n = 198). Median follow-up was 34 months. Median dose to point A was 81 Gy.

RESULTS

Five-year actuarial incidence of overall (all grades) and severe (grade 3/4) late toxicities in the rectum, bladder, small intestine and subcutaneous tissue were 12.3% and 1.1%, 11.2% and 1.2%, 9.2% and 0.2%, and 23.1% and 1.2%, respectively. Vaginal adhesions were seen in 29.6% of cases and stenosis in 33.9% of cases. On multivariate analysis, factors adversely affecting overall incidence of proctitis were anterior-posterior (AP) separation of patient more than 18 cm and presence of comorbid diseases. Presence of comorbid diseases was the only factor affecting the incidence of severe proctitis (grade 3/4). AP separation more than 18 cm adversely affected the incidence of cystitis, both overall and severe. Late toxicities (all grades) in small bowel were increased in subsets, like women younger than 50 years and women with comorbid diseases, but no factor emerged as significant for incidence of severe toxicities. Subcutaneous fibrosis was significantly higher in patients with AP separation over 18 cm, those treated by cobalt machines and those who received EBRT only. Severe subcutaneous fibrosis was influenced by the use of EBRT alone. Overall incidence of vaginal toxicity was higher in women whose overall treatment time (OTT) was shorter and in women who received ICRT. Vaginal stenosis was higher in elderly women and in women who received ICRT by low dose rate.

CONCLUSIONS

Even with telecobalt machines, impressive results with acceptable late toxicity can be achieved in the treatment of cancer of the cervix using an ideal combination of EBRT with ICRT.

Mapping pelvic lymph nodes: Guidelines for delineation in intensity-modulated radiotherapy

PURPOSE

To establish guidelines for delineating the clinical target volume for pelvic nodal irradiation by mapping the location of lymph nodes in relation to the pelvic anatomy.

METHODS AND MATERIALS

Twenty patients with gynecologic malignancies underwent magnetic resonance imaging with administration of iron oxide particles. All visible lymph nodes were outlined. Five clinical target volumes were generated for each patient using modified margins of 3, 5, 7, 10, and 15 mm around the iliac vessels. The nodal contours were then overlaid and individual nodes analyzed for coverage. The volume of normal tissue within each clinical target volume and planning target volume was also measured to aid selection of the margin that could provide maximal nodal, but minimal normal tissue, coverage.

RESULTS

In total, 1216 nodal contours were evaluated. The nodal coverage was 56%, 76%, 88%, 94%, and 99% using vessel margins of 3, 5, 7, 10, and 15 mm, respectively. The mean volume of bowel within the planning target volume was 146.9 cm3 with a 7-mm margin, 190 cm3 with a 10-mm margin, and 266 cm3 with a 15-mm margin. Minor modification to the 7-mm margin ensured 99% coverage of the pelvic nodes.

CONCLUSION

Blood vessels with a modified 7-mm margin offer a good surrogate target for pelvic lymph nodes. By making appropriate adjustments, coverage of specific nodal groups may be increased and the volume of normal tissue irradiated decreased. On the basis of these findings, recommended guidelines for outlining pelvic nodes have been produced.

Comparison of late toxicity between continuous low-dose-rate and pulsed-dose-rate brachytherapy in cervical cancer patients

PURPOSE

To compare survival and severe late radiation toxicity between patients who received continuous low-dose-rate (LDR) brachytherapy (BT) and pulsed-dose-rate (PDR) BT for cervical cancer.

METHODS AND MATERIALS

A retrospective review of cervical cancer patients who underwent primary radiotherapy with or without concurrent cisplatin was performed. Late Grade 3 or worse toxicities were assessed using the National Cancer Institute Common Toxicity Criteria. The study endpoints were overall and disease-free survival and the probability of severe late toxicity.

RESULTS

A total of 109 patients (65.7%) received LDR BT and 57 (34.3%) received PDR BT. Seventy patients received concurrent chemotherapy with cisplatin. The 3-year overall survival and disease-free survival rate was 70% and 57% for the LDR group and 82% and 70% for the PDR group, respectively (p = 0.25 and p = 0.19). The 3-year probability rate for late Grade 3 or worse toxicity was 7.4% for LDR BT patients and 7.6% for PDR BT patients, respectively (p = 0.69) and 6.9% and 7.6%, respectively, for concurrent chemotherapy vs. none (p = 0.69).

CONCLUSION

No difference was found in severe late toxicity, overall survival, or disease-free survival between the LDR and PDR groups.

Dosimetric parameters that predict late rectal complications after curative radiotherapy in patients with uterine cervical carcinoma

BACKGROUND

Late rectal complication (LRC) was a major late complication in patients with uterine cervical carcinoma who were treated with a combination of external beam radiotherapy (EBRT) and high-dose-rate intracavitary irradiation (HDR-ICR). For the current study, the authors retrospectively evaluated dosimetric parameters that were correlated with LRC > or = Grade 2 in patients with uterine cervical carcinoma who were treated with curative radiotherapy, and they analyzed the appropriate dose estimates to the rectum that were predictive for LRC > or = Grade 2.

METHODS

Between July 1994 and September 2002, 157 patients who were diagnosed with Stage IB-IIIB cervical carcinoma and were treated with definitive radiotherapy were included. EBRT (41.4-66 grays [Gy] in 23-33 fractions) to the whole pelvis was delivered to all patients, with midline shielding performed after a 36-50.4 Gy external dose. HDR-ICR (21-39 Gy in 6-13 fractions to Point A) was administered at a rate of 2 fractions weekly after midline shielding of EBRT. LRC was scored using Radiation Therapy Oncology Group criteria. The total biologically effective dose (BED) at specific points, such as Point A (BED(Point A)), rectal point (BED(RP)), and maximal rectal point (BED(MP)), was determined by a summation of the EBRT and HDR-ICR components, in which the alpha/beta ratio was set to 3. Analyzed parameters included patient age, tumor size, stage, concurrent chemotherapy, ICR fraction size, RP ratio (dose at the rectal point according to the Point A dose), MP ratio (dose at the maximal rectal point according to the Point A dose), EBRT dose, BED(Point A), BED(RP), and BED(MP).

RESULTS

The 5-year actuarial overall rate of LRC > or = Grade 2 in all patients was 18.4%. Univariate analysis showed that the RP ratio, MP ratio, EBRT dose, BED(Point A), BED(RP), and BED(MP) were correlated with LRC > or = Grade 2 (P < 0.05). Multivariate analysis showed that, of all clinical and dosimetric parameters evaluated, only BED(RP) was correlated with LRC > or = Grade 2 (P = 0.009). The 5-year actuarial rate of LRC > or = Grade 2 was 5.4% in patients with a BED(RP) < 125 Gy(3) and 36.1% in patients with a BED(RP) > or = 125 Gy(3) (P < 0.001).

CONCLUSIONS

BED(RP) was a useful dosimetric parameter for predicting the risk of LRC > or = Grade 2 and should be limited to < 125 Gy(3) whenever possible to minimize the risk of LRC > or = Grade 2 in patients with uterine cervical carcinoma who are treated with a combination of EBRT and HDR-ICR. Cancer 2005.

Results of radiotherapy alone in the treatment of carcinoma of uterine cervix: a retrospective analysis of 1069 patients

Carcinoma of the uterine cervix is the most common malignancy affecting women in developing countries like India. This retrospective study was made to analyze our results of radiotherapy alone in the treatment of carcinoma cervix. Between January 1996 and December 2001, 1069 patients of carcinoma cervix were treated at our center with external beam radiotherapy (EBRT) and intracavitary radiotherapy (871) or EBRT alone (198). The median dose to point A was 81 Gy. Overall survival (OS), disease-free survival (DFS), and pelvic control at 5 years were 51.8%, 49.4%, and 63.9%, respectively. For the patients who could receive intracavitary radiotherapy (871), the OS, DFS, and pelvic control rates were 60.7%, 58.6%, and 73.5%, respectively. On multivariate analysis, bulk, overall treatment time (OTT) and response to EBRT were found to affect OS and DFS independently. Similarly, OTT, response to EBRT, stage, and age were the factors that influenced pelvic control. Incidence of severe late toxicities (grade 3/4) in the rectum, bladder, small intestine, and skin were 1.1%, 1.2%, 0.2%, and 1.2%, respectively. In developing countries like India, where chemoradiation can be afforded by a minority only, judicious use of radiotherapy still produces satisfactory results with acceptable toxicity. The addition of chemotherapy may be beneficial in patients with adverse prognostic factors.

Conventional, conformal, and intensity-modulated radiation therapy treatment planning of external beam radiotherapy for cervical cancer: The impact of tumor regression

PURPOSE

Investigating the impact of tumor regression on the dose within cervical tumors and surrounding organs, comparing conventional, conformal, and intensity-modulated radiotherapy (IMRT) and the need for repeated treatment planning during irradiation.

METHODS AND MATERIALS

Fourteen patients with cervical cancer underwent magnetic resonance (MR) imaging before treatment and once during treatment, after about 30 Gy. Target volumes and critical organs were delineated. First conventional, conformal, and IMRT plans were generated. To evaluate the impact of tumor regression, we calculated dose-volume histograms for these plans, using the delineations of the intratreatment MR images. Second conformal and IMRT plans were made based on the delineations of the intratreatment MR images. First and second plans were compared.

RESULTS

The average volume receiving 95% of the prescribed dose (43 Gy) by the conventional, conformal, and IMRT plans was, respectively, for the bowel 626 cc, 427 cc, and 232 cc; for the rectum 101 cc, 90 cc, and 60 cc; and for the bladder 89 cc, 70 cc, and 58 cc. The volumes of critical organs at this dose level were significantly reduced using IMRT compared with conventional and conformal planning (p < 0.02 in all cases). After having delivered about 30 Gy external beam radiation therapy, the primary gross tumor volumes decreased on average by 46% (range, 6.1-100%). The target volumes on the intratreatment MR images remained sufficiently covered by the 95% isodose. Second IMRT plans significantly diminished the treated bowel volume, if the primary gross tumor volumes decreased >30 cc.

CONCLUSIONS

Intensity-modulated radiation therapy is superior in sparing of critical organs compared with conventional and conformal treatment, with adequate coverage of the target volumes. Intensity-modulated radiation therapy remains superior after 30 Gy external beam radiation therapy, despite tumor regression and internal organ motion. Repeated IMRT planning can improve the sparing of the bowel and rectum in patients with substantial tumor regression.

A randomised comparison of two brachytherapy devices for the treatment of uterine cervical carcinoma

Two brachytherapy applicators commonly used in the treatment of uterine cervical carcinoma, the Henschke shielded and Fletcher-Suit-Declos, were randomly and prospectively compared in vivo in 20 patients. Based on two-dimensional planning and the ICRU-38 bladder and rectal reference points, an advantage for the shielded Henschke applicator was demonstrated.

New radiation techniques in gynecological cancer

Radiation therapy has been a major therapeutic modality for eradicating malignant tumors over the past century. In fact, it was not long after the discovery of radium that the first woman with cervical cancer underwent intracavitary brachytherapy. Progress in the way that this cytotoxic agent is manipulated and delivered has seen an explosive growth over the past two decades with technological developments in physics, computing capabilities, and imaging. Although radiation oncologists are educated in and familiar with the wealth of new revolutionary techniques, it is not easy for other key members of the team to keep up with the rapid progress and its significance. However, to fully exploit these enormous gains and to communicate effectively, medical and gynecological oncologists are expected to be aware of state-of-the-art radiation oncology. Here, we elucidate and illustrate contemporary techniques in radiation oncology, with particular attention paid to the external beam radiotherapy used for adjuvant and primary definitive management of malignancies of the female pelvis.

Dosimetric factors predicting severe radiation-induced bowel complications in patients with cervical cancer: combined effect of external parametrial dose and cumulative rectal dose

OBJECTIVE

The purpose of this study was to analyze dosimetric factors of radiation-induced severe bowel complications among patients with cervical cancer.

METHODS

We reviewed 297 patients of stage IB-IVA cervical cancer managed by curative-intent radiotherapy from May 1993 through December 1997. Whole-pelvic irradiation of external beam radiation therapy (EBRT) (34.2-48.6 Gy/19-27 fractions) was delivered to all patients. Two hundred and three patients received additional bilateral parametrial boost (3.6-18 Gy/2-10 fractions). High dose-rate (HDR) intracavitary brachytherapy (ICBT), 16-24 Gy/5 fractions to Point A, was given after external irradiation. Cumulative rectal biologically effective dose (CRBED) at rectal reference point was determined by summation of EBRT and ICBT component.

RESULTS

The 5-year incidences of Grade 3-4 enterocolitis and proctitis were 10% and 7%, respectively. Both complications were associated with external parametrial dose (PMD) and CRBED. Interaction of CRBED and PMD was noted in multivariate analysis of enterocolitis (P < 0.001) and proctitis (P < 0.001). In CRBED > or = 100 Gy(3) group, PMD was an independent factor in enterocolitis (P = 0.010) and proctitis (P = 0.039). In PMD > or = 54 Gy group, CRBED was an independent factor in enterocolitis (P = 0.003) and proctitis (P = 0.036). Patients with both PMD > or = 54 Gy and CRBED > or = 100 Gy(3) had higher incidence of 5-year enterocolitis (26%) (P < 0.001) and proctitis (17%) (P < 0.001) than other dose groups.

CONCLUSION

Radiation-induced severe bowel complications are association on both high PMD and high CRBED. We do not suggest both external PMD > or = 54 Gy and CRBED > or = 100 Gy(3) for treatment of cervical cancer due to unacceptably high incidence of severe bowel complications.

Hyperbaric oxygen therapy in the treatment of radio-induced lesions in normal tissues: a literature review

Late complications are one of the major factors limiting radiotherapy treatment, and their treatment is not codified. Hyperbaric oxygen (HBO) has been used in combination with radiotherapy for over half a century, either to maximise its effectiveness or in an attempt to treat late complications. In this latter case, retrospective trials and case reports are prevailing in literature. This prompted European Society for Therapeutic Radiotherapy and Oncology and European Committee for Hyperbaric Medicine to organise a consensus conference in October 2001, dealing with the HBO indications on radiotherapy for the treatment and prevention of late complications. This updated literature review is part of the documents the jury based its opinion on. A systematic search was done on literature from 1960 to 2004, by only taking into account the articles that appeared in peer review journals. Hyperbaric oxygen treatment involving complications to the head and neck, pelvis and nervous system, and the prevention of complications after surgery in irradiated tissues have been studied. Despite the small number of controlled trials, it may be indicated for the treatment of mandibular osteoradionecrosis in combination with surgery, haemorrhagic cystitis resistant to conventional treatments and the prevention of osteoradionecrosis after dental extraction, whose level of evidence seems to be the most significant though randomised trials are still necessary. The other treatment methods are also outlined for each location.

Acute and long-term toxicity following radiotherapy alone or in combination with chemotherapy for locally advanced cervical cancer

Randomised studies in locally advanced cervical cancer patients showed that cisplatin should be given concurrently with radiotherapy, because of a better long-term survival compared to radiotherapy alone. This increases the relevance of treatment related toxicity. This review summarises the acute and long-term toxicity of radiotherapy given with or without chemotherapy for cervical cancer. Acute toxicity (all grades) of radiotherapy is reported in 61% of the patients in the rectosigmoid, in 27% as urological, in 27% as skin and in 20% as gynaecological toxicity. Moderate and severe morbidity consists of 5% to 7% gastrointestinal and 1% to 4% genitourinary toxicity. Adding chemotherapy to radiotherapy increases acute haematological toxicity to 5% to 37% of the patients and nausea and vomiting in 12% to 14%. Late effects of radiotherapy include gastrointestinal, urological, female reproductive tract, skeletal and vascular toxicity, secondary malignancies and quality of life issues. For at least 20 years after treatment, new side effects may develop. Gastrointestinal toxicity usually occurs in the first 2 years after treatment in about 10% of the patients. The incidence of moderate and severe urological toxicity can increase up to 10% and rises over time. Gynaecological toxicity usually occurs shortly after treatment while skeletal and vascular toxicity can occur years to decades later. Thus far, no increase in late toxicity has been observed after the addition of cisplatin to radiotherapy. Finally, methods to prevent or decrease late toxicity and therapeutical options are discussed. However, most randomised studies still have a limited follow-up period.

Conventional 3D conformal versus intensity-modulated radiotherapy for the adjuvant treatment of gynecologic malignancies: a comparative dosimetric study of dose–volume histograms☆

OBJECTIVE

The goals of this study were to evaluate the feasibility of pelvic intensity-modulated radiotherapy (IMRT) in the adjuvant treatment of gynecologic malignancies and to compare the dose-volume histograms (DVHs) and determine the potential impact on acute and long-term toxicity based on the dose to target and nontarget tissues for both planning techniques.

METHODS

Ten consecutive patients referred for adjuvant radiotherapy for gynecologic malignancies at the University of Pittsburgh School of Medicine and Magee-Womens Hospital were selected for CT-based treatment planning using the ADAC 3D version 4.2g and the NOMOS Corvus IMRT version 4.0. Normal tissues and critical structures were contoured on axial CT slices by both systems in conjunction with a gynecologic radiologist. These regions included internal, external, and common iliac nodal groups, rectum, upper 4 cm of vagina, bladder, and small bowel. Conventional treatment planning included 3D four-field box using 18-MV photons designed to treat a volume from the L(5)/S(1) border superiorly to the bottom of the ischial tuberosity on the AP/PA field and shaped blocks on the lateral fields to minimize the dose to the rectum and small bowel. A seven-field technique using 6-MV photons was used for IMRT. Restraints on small bowel for IMRT were set at 23.0 Gy +/- 5% and 35.0 Gy+/- 5% for the rectum and 37.5 Gy +/- 5% for the bladder while simultaneously delivering full dose (45.0 Gy) to the intrapelvic nodal groups in 1.8-Gy daily fractions. The dose-volume histograms where then compared for both treatment delivery systems.

RESULTS

The volume of each organ of interest (small bowel, bladder, and rectum) receiving doses in excess of 30 Gy was compared in the 3D and IMRT treatment plans. The mean volume of small bowel receiving doses in excess of 30 Gy was reduced by 52% with IMRT compared with 3D. A similar advantage was noted for the rectum (66% reduction) and the bladder (36% reduction). The nodal regions at risk and the upper vagina all received the prescribed dose of 45.0 Gy.

CONCLUSIONS

Intensity-modulated radiotherapy appears to offer several advantages over conventional 3D radiotherapy (3D CRT) planning for adjuvant radiotherapy for gynecologic malignancies. These include a significant reduction in treatment volume for bladder, rectum, and small bowel. It is anticipated that this reduction in volume of normal tissue irradiated would translate into overall reduction in acute and potentially late treatment-related toxicity. Prospective trials are necessary to better evaluate the advantages in a larger group of patients.

Bladder and rectum dose defined from MRI based treatment planning for cervix cancer brachytherapy: comparison of dose-volume histograms for organ contours and organ wall, comparison with ICRU rectum and bladder reference point

PURPOSE

To analyze the correlation between dose-volume histograms based on organ contour and organ wall delineation for bladder and rectum, and to compare the doses to these organs with the absorbed doses at the ICRU bladder and rectum reference points.

MATERIAL AND METHODS

Individual MRI based brachytherapy treatment planning was performed in 15 patients as part of a prospective comparative trial. The external contours and the organ walls were delineated for the bladder and rectum in order to compute the corresponding dose-volume histograms. The minimum dose in 2 cm(3), 5 cm(3) and 10 cm(3) volumes receiving the highest dose were referred to as [D2], [D5] and [D10] and compared with the absorbed dose at the ICRU rectum and bladder reference point.

RESULTS

The bladder (bext) and rectal (rext) doses derived from external contours and computed for volumes of 2 cm(3) [D2], provided a good estimate for the doses computed for the organ walls (bw and rw) only (mean ratio [D2](bext)/[D2](bw)=1.1+/-0.2 and [D2](rext)/[D2](rw)=1.2+/-0.1, respectively). This correspondence was no longer true when larger volumes were considered (5 and 10 cm(3)). The dose at the ICRU rectum reference point did overestimate the dose computed for 2 cm(3) of the rectum wall (mean ratio: 1.5+/-0.4). In contrast, the dose at the ICRU bladder reference point did-in the case of inappropriate topographic location of the balloon-underestimate the dose computed for 2 cm(3) of the bladder wall (overall mean ratio: 0.9+/-0.4).

CONCLUSION

For clinical applications, when volumes smaller than 5 cm(3) are considered, the dose-volume histograms computed from external organ contours for the bladder and rectum can be used instead of dose-volume histograms computed for the organ walls only. External organ contours are indeed easier to obtain. The dose at the ICRU rectum reference point provides a good estimate of the rectal dose computed for volumes smaller than 2 cm(3) [D2] only for a midline position of the rectum. The ICRU bladder reference point provides a good estimate of the dose computed for the bladder wall [D2] only in cases of appropriate balloon position.

Results and complications of high dose rate and low dose rate brachytherapy in carcinoma of the cervix: Cerrahpaşa experience

PURPOSE

To evaluate the results and complications of treatment with high dose rate (HDR) compared to low dose rate (LDR) brachytherapy in cervical carcinoma.

METHODS

Three hundred and seventy patients who were treated with external irradiation and intracavitary brachytherapy and followed for more than 2 years between 1978 and 1998 have been recently updated. The low dose rate group consisted of 77 cases treated between 1978 and 1982 and HDR group consisted of 293 cases treated between 1982 and 1998. All patients first received external irradiation with 60Co or 9-18 MV photons and a median dose of 54 Gy was given in 6 weeks. In the LDR group, intracavitary treatment was given with Manchester applicators loaded with radium (30 mg) in an intrauterine tube and 20 mg in vaginal ovoids. The dose delivered to point A was on average 32 Gy in one application. In the HDR group, a total dose of 24 Gy was given to point A in three insertions 1 week apart. The dose rate was 0.62 Gy at point A.

RESULTS

The 5-year pelvic control rate was found to be 73% in the HDR group, compared with 86% in the radium group for stage I cases. In stage IIB and IIIB cases, the rates were 68% and 45% for HDR and 65% and 53% for LDR, respectively. In all stages, there was no statistical difference in pelvic control and survival rates between the two groups. Overall incidence of late complications was found as 31.1% and 31.9% in HDR and LDR groups, respectively. The grade 2-4 late complication rate was 14% in the HDR group compared to 19% in the LDR group (P>0.05).

CONCLUSION

HDR brachytherapy in the management of the cervix appears to be a safe and efficacious approach. Pelvic control, survival and complications rates are quite similar when compared with LDR.

Treatment results of high-dose-rate remote afterloading brachytherapy for cervical cancer and retrospective comparison of two regimens

PURPOSE

To review the treatment results and complications of high-dose-rate (HDR) intracavitary brachytherapy for patients with carcinoma of the cervix in a single institute and to compare them with those of low-dose-rate (LDR) brachytherapy reported in the literature.

METHODS AND MATERIALS

Two hundred twenty patients with carcinoma of the cervix were treated by primary radiotherapy between 1991 and 1998. The median age was 63 (range 24-84). The distribution according to Federation of Gynecology and Obstetrics (FIGO) staging system was as follows: Stage IB, 11.4%; IIA, 9.1%; IIB, 50.9%; IIIA, 3.6%; IIIB, 23.2%; and IVA, 1.8%. They were treated with whole pelvic irradiation giving 40 Gy to the midplane in 20 fractions over 4 weeks. This was followed by parametrial irradiation, giving 16-20 Gy in 8-10 fractions. HDR intracavitary brachytherapy was given weekly, with a dose of 7 Gy to point A for three fractions and, starting from 1996, 6 Gy weekly for four fractions. The median overall treatment time was 50 days (range 42-73 days). The median follow-up time was 4.7 years (range 3 months to 11.1 years). Multivariate analysis was performed using the Cox regression proportional hazards model.

RESULTS

The complete remission rate after radiotherapy was 93.4% (211/226). The 5-year actuarial failure-free survival (FFS) and cancer-specific survival (CSS) rates for stage IB, IIA, IIB, IIIA, IIIB, and IVA were 87.7% and 86.6%, 85% and 85%, 67.8% and 74%, 46.9% and 54.7%, 44.8% and 50.4%, 0% and 25%, respectively. On multivariate analysis, young age (< 50) (p = 0.0054), adenocarcinoma (p = 0.0384), and stage (p = 0.0005) were found to be independent poor prognostic factors. The 5-year actuarial major complication rates (Grade 3 or above) were as follows: proctitis, 1.0%; cystitis, 0.5%; enteritis, 1.3%; and overall, 2.8%. On multivariate analysis, history of pelvic surgery was a significant prognosticator. The two HDR fractionation schedules were not a significant prognosticator in predicting disease control and complications.

CONCLUSION

Our experience in treating cervical cancer with HDR intracavitary brachytherapy is encouraging. Our treatment results and complication rates were compatible with those of the LDR series. Further studies are eagerly awaited to better define the optimal fractionation schedule for HDR brachytherapy and the schedule on how chemotherapy may be combined with it.

Radiotherapy alone in the treatment of uterine cervix cancer with telecobalt and low-dose-rate brachytherapy: retrospective analysis of results and variables

PURPOSE

This retrospective analysis aims to report results and variables from patients with cervix cancer treated by radiation therapy alone with telecobalt and low-dose-rate brachytherapy (LDRB).

METHODS AND MATERIALS

Between September 1989 and September 1995, 190 patients with histologic diagnosis of cervix carcinoma were treated with telecobalt for external beam radiotherapy (EBR), followed by one or two insertions of LDRB. Stage distribution according to patients was the following: IB, 12; IIA, 4; IIB, 105; and IIIB, 69. Median dose of EBR at whole pelvis was 40 Gy, and median parametrial doses for Stages II and III patients were 50 Gy and 60 Gy, respectively. Median doses of LDRB at point A for patients treated with one and two insertions were 38 Gy and 50 Gy, respectively.

RESULTS

Median follow-up time was 70 months (range: 8-127 months). Overall survival, disease-free survival, and 5-year local control of patients at Stages I, II, and III were 83%, 78%, and 46%; 83%, 82%, and 49%; and 92%, 87%, and 58%, respectively. Overall incidence of late complications in the rectum, small bowel, and urinary tract was 15.3% (19/190), 4.2% (8/190), and 6.8% (13/190), respectively. The actuarial 5-year rectal, small bowel, and urinary incidence of late complications was 16.1%, 4.6%, and 7.6%, respectively. Clinical stage was the only significant variable for overall 5-year survival (p = 0.001), for disease-free survival (p = 0.001), and for local control (p = 0.001). Stage II patients more than 50 years old had better disease-free survival and local control at 5 years (p = 0.004). None of the analyzed variables influenced the actuarial 5-year incidence of late complications.

CONCLUSIONS

Results of this series suggest that the use of telecobalt equipment for EBR with doses up to 50 Gy at whole pelvis, prior to brachytherapy, is an acceptable technique for radiation therapy alone in the treatment of cervix cancer, especially in developing countries, including Brazil, where telecobalt machines still prevail.

[Brachytherapy in cervix cancers: development of techniques and concepts]

Brachytherapy plays an important role in the treatment of patients with cervical carcinoma. Technical modalities have evolved during the last years and have benefited from imaging modalities development, specially MRI. Imaging modalities contribute to a better knowledge of tumoral extension and critical organs. Ultrasound during brachytherapy has led to the almost complete eradication of uterine perforation. In the future, a more systematic use of systems allowing optimization may induce a better dose distribution in the tumor as well as in the critical organs. Recent data provided information in favor of a better analysis in the relative role of dose-rate, total dose and treated volume and their influence on the local control and complication incidence. Concomitant radiochemotherapy represents a standard in the treatment of patients with tumoral size exceeding 4 cm. Some questions still remain: is concomitant chemotherapy of benefit during brachytherapy? Is there any place for complementary surgery, specially in patients with complete response after external irradiation with concomitant chemotherapy and brachytherapy? In order to answer the former question, a phase III randomized trial is going to start, with the Fédération Nationale des Centres de Lutte Contre le Cancer as a promoter.

Intensity-modulated radiation therapy in gynecologic malignancies

Radiation therapy (RT) is commonly used in the treatment of gynecologic malignancies. Unfortunately, RT exposes patients to a wide variety of sequelae. Concerns over toxicity also limit the use of higher doses in select patients. To improve the efficacy of conventional RT and to explore the possibility of dose escalation, we have turned to the use of intensity-modulated RT (IMRT). This report reviews our preclinical studies, implementation, and clinical experience to date with IMRT for gynecologic malignancies.

Operable Stages IB and II cervical carcinomas: a retrospective study comparing preoperative uterovaginal brachytherapy and postoperative radiotherapy

PURPOSE

To evaluate our data concerning prognostic factors and treatment toxicity in a series of operable cervical carcinomas.

METHODS AND MATERIALS

Between May 1972 and January 1994, 414 patients with cervical carcinoma, staged according to the 1995 FIGO staging system (286 Stage IB1, 38 Stage IB2, 56 Stage IIA, and 34 Stage IIB with 1/3 proximal parametrial involvement), underwent radical hysterectomy with (n = 380) or without (n = 34) bilateral pelvic lymph node dissection (N+: n = 68). Group I included 168 patients who received postoperative radiation therapy (RT): 64 patients had low-dose-rate vaginal brachytherapy with a median total dose (MTD) of 50 Gy; 93 patients had external beam pelvic RT (EBPRT) with an MTD of 45 Gy over 5 weeks, followed by low-dose-rate vaginal brachytherapy (MTD: 20 Gy); and 11 patients had EBPRT alone (MTD: 50 Gy over 6 weeks). Group II included 246 patients treated with preoperative low-dose-rate uterovaginal brachytherapy (MTD: 65 Gy); 32 of these 246 patients also received postoperative EBPRT (MTD: 45 Gy over 5 weeks) delivered to the parametria and pelvic nodes. Mean follow-up from the beginning of treatment was 106 months.

RESULTS

First events included isolated locoregional recurrences (35 patients), isolated distant metastases (27 patients), and locoregional recurrences with synchronous metastases (13 patients). The 10-year disease-free survival (DFS) rate was 88% for Stage IB1, 44% for Stage IB2, 65% for Stage IIA, and 48% for Stage IIB. Multivariate analysis showed that independent factors influencing the probability of DFS were as follows: cervical site (exocervical or endocervical vs. both endo- and exocervical, relative risk [RR]: 1.77, p = 0.047), vascular space invasion (no vs. yes, RR: 1.95, p = 0.041), age (>51 years vs. <or=51 years, RR: 1.90, p = 0.013), 1995 FIGO staging system (IB1 vs. IIA, RR: 2.95, p = 0.004; IB1 vs. IB2, RR: 3.49, p = 0.0009; and IB1 vs. IIB, RR: 4.54, p = 0.00002), and histologic pelvic lymph node involvement (N- vs. N+, RR: 2.94, p = 0.00009). The sequence of adjuvant RT did not influence the probability of DFS (Group I vs. Group II, p = 0.10). In Group II, after univariate analysis, DFS was significantly influenced by histologic residual cervical tumor in the hysterectomy specimen (yes vs. no: 71% vs. 93%, respectively, p < 10(-6)) and by the size of the residual tumor (<or=1 cm vs. >1 cm: 83% vs. 41%, respectively, p = 0.001). The overall postoperative complication rate was 10% in Group I and 9% in Group II (p = 0.7). The rate of postoperative ureteral complications requiring surgical intervention was lower in Group I than in Group II (0.6% vs. 2.3%, respectively, p = 0.03). The overall 10-year rate for Grade 3 and 4 late radiation complications was 10.4%. Postoperative EBPRT significantly increased the 10-year rate for Grade 3 and 4 late radiation complications (yes vs. no: 22% vs. 7%, respectively, p = 0.0002).

CONCLUSION

The prognosis for patients with cervical carcinoma was not influenced by the sequence of adjuvant RT (preoperative uterovaginal brachytherapy vs. postoperative RT) for Stages IB, IIA, and IIB with 1/3 proximal parametrial involvement. However, postoperative EBPRT increased the risk of late radiation complications.

[Operable stage IB and II cancer of the uterine neck: retrospective comparison between preoperative utero-vaginal curietherapy and initial surgery followed by radiotherapy]

PURPOSE

To identify prognostic factors and treatment toxicity in a series of operable stages IB and II cervical carcinomas.

PATIENTS AND METHODS

Between May 1972 and January 1994, 414 patients (pts) with cervical carcinoma staged according to the 1995 FIGO staging system underwent radical hysterectomy with (n = 380) or without (n = 34) bilateral pelvic lymph node dissection. Lateral ovarian transposition to preserve ovarian function was performed on 12 pts. The methods of radiation therapy (RT) were not randomised and depended on the usual practices of the surgical teams. Group I: 168 pts received postoperative RT (64 pts received vaginal brachytherapy alone [mean total dose (MD): 50 Gy], 93 pts had external beam pelvis RT (EBPRT) [MD: 45 Gy over 5 weeks] followed by vaginal brachytherapy [MD: 20 Gy], and 11 pts had EBPRT alone [MD: 50 Gy over 6 weeks]. Group II: 246 pts received preoperative utero-vaginal brachytherapy [MD: 65 Gy], and 32 of theses 246 pts also received postoperative EBPRT [MD: 45 Gy over 5 weeks] delivered to the parametric and the pelvic lymph nodes with a midline pelvic shield. The mean follow-up was 106 months.

RESULTS

The 10-year disease-free survival (DFS) rate was 80%. From 75 recurrences, 35 were isolated locoregional. Multivariate analysis showed that independent factors decreasing the probability of DFS were: both exo and endocervical tumour site (p = 0.047), lymph-vascular space invasion (p = 0.041), age < or = 51 yr (p = 0.013), 1995 FIGO staging system (stage IB1 vs stage IIA, p = 0.004, stage IB1 vs stage IB2, p = 0.0009, and stage IB1 vs stage IIB with 1/3 proximal parametrical infiltration, p = 0.00002), and histological pelvic involved lymph nodes (p = 0.00009). Methods of adjuvant RT did not influence the probability of DFS (group I vs group II, p = 0.10). The postoperative complication rate was 10.2% in group I and 8.9% in group II (p = 0.7) but the postoperative urethral complication rate necessitating surgical intervention with reimplantation was lower in group I than in group II (0.6% vs 2.3%, respectively, p = 0.03). The 10-year rate for grade 3 and 4 late radiation complications according to the LENT-SOMA scoring system was 10.4%. EPRT significantly increased the 10-year rate for grade 3 and 4 late radiation complications (yes vs no: 22% vs 7%, respectively, p = 0.0002).

CONCLUSION

In our series, the methods of adjuvant RT (primary surgery vs preoperative uterovaginal brachytherapy) do not seem to influence the prognosis of the stage IB, IIA, and IIB (with 1/3 proximal parametrical involvement only) cervical carcinomas. The postoperative EPRT applied according to histopathological risk factors after surgical treatment increases the risk of late radiation complications.

The effect of overall treatment time on the survival and toxicity of radical radiotherapy for cervical carcinoma

BACKGROUND AND PURPOSE

Overall treatment time is an important factor in the outcome of radical radiotherapy in head and neck, bladder and lung cancer and in cervix cancer treated over more than 7 weeks. This study analysed the effect of prolongation of overall treatment time on survival and late morbidity for patients receiving radical radiotherapy for cervical cancer treated with a 4-week regimen.

MATERIALS AND METHODS

Using the departmental SAS data-base we identified all patients with cervix cancer treated between 1974 and 1988 and investigated the 647 patients who received 20 fractions of external beam radiotherapy plus intracavitary therapy with a total dose to point A of at least 60Gy. A retrospective case-note review identified tumour and treatment-related variables.

RESULTS

Four hundred and twenty-five (66%) patients had at least one gap in treatment. Seventy-nine gaps (11%) were due to unavoidable patient or treatment-related causes. We could not find an effect of a treatment gap (P=0.43) or an increased overall treatment time (P=0.79) on the cause specific survival of patients. There was significantly more grade 4 morbidity in those patients treated over a short period (29-32 days) compared to the rest (P=0.005), possibly related to the loss of radiotherapy-free days to weekend intracavitary insertions.

CONCLUSIONS

We could not demonstrate a significant effect of overall treatment time in this series of patients, almost all of whom were treated in less than 7 weeks. Those patients treated over the shortest period had an increased incidence of late morbidity.

[Epidermoid carcinoma of the uterine cervix at operable bulky stages IB and II treated with combined primary radiation therapy and surgery]

PURPOSE

To identify prognostic factors and treatment toxicity in a series of operable bulky stages I and II cervical carcinomas treated with a therapeutic modality combining primary irradiation and surgery.

PATIENTS AND METHODS

Between July 1982 and May 1996, 66 patients with bulky squamous-cell cervical carcinomas (stage IB2, IIA, and IIB with 1/3 proximal parametrial invasion) underwent primary external beam pelvic radiation therapy (37.40 Gy to 40 Gy over 4.5 weeks) and low-dose-rate uterovaginal brachytherapy (20 Gy) followed, 5 to 6 weeks later, by class II modified radical hysterectomy with bilateral pelvic lymphadenectomy. The four last patients received concomitant chemotherapy during the first and the fourth radiation week combining 5-FU and cisplatin. A clinical pelvic lymph node involvement had been observed in 7 patients. The clinical median tumor size was 5 cm in diameter (range: 4.5-8 cm). The median follow-up was 97 months.

RESULTS

Pathologic complete tumor response in specimen of hysterectomy were observed in 46 patients. Six patients had pathologic unilateral iliac lymph node involvement. The 5- and 10-year specific survival rates were 79 and 74%, respectively. The 5- and 10-year disease-free survival rates were 76% and 71%, respectively. The 10-year local control rate was 85%. The 10-year probability for pelvic recurrence was significantly influenced by the pathologic tumor response: 26% in the residual group vs 5% in the complete tumor response group, P = 0.024). After multivariate analysis, the independent factors decreasing the probability of disease-free survival were: pathologic pelvic lymph node involvement (P = 0.029), and parametrial invasion (P = 0.031). Five late severe complications requiring surgical intervention were observed: 2 bowel obstructions, 1 ureteral stenosis, 1 vesicovaginal fistula, and 1 radiation induced unilateral femoral necrosis.

CONCLUSION

A good local control is obtained after combined primary radiation therapy and surgery for bulky stages I and II cervical carcinomas. In our more recent practice, the treatment combines primary concomitant chemoradiation followed by surgery including pelvic and para-aortic lymphadenectomy.

Radiation therapy for cervix carcinoma: benefits of individualized dosimetry

This study is a presentation of the prospective collection of data on patients treated by radical radiotherapy at Westmead Hospital between December 1989 and December 1998. The impact of the routine use of individualized dosimetry and lower brachytherapy dose on patients was examined, by comparing the historical series of patients treated between 1989 to 1991 to the later patients treated with inividualised dosimetry. There were 163 patients treated with external beam and intracavitary radiotherapy during this period. Histology was squamous carcinoma in 80% (132 patients), adenocarcinoma in 13% (22 patients), and adenosquamous carcinoma in 6% (9 patients). Patients were generally treated with 50 Gy in 25 fractions to the pelvis followed by 1 low dose rate caesium intracavitary brachytherapy insertion. Patients who had dosimetry generally received 20 Gy to point A via the insertion compared to 30 Gy in the non-dosimetry group. Median follow-up was 62 months. Only 22% (18) of patients failed with disease outside the pelvis. Pelvic control was similar in the patients who had dosimetry as opposed to no dosimetry (P=0.8). In the dosimetry group there were less grade III or higher bowel toxicity (P=0.01) and less vaginal fistulae (P=0.03). The actuarial two-year survival was 56.2% in the no dosimetry group and 68.6% in the dosimetry group. When controlled for stage and performance status patients who had dosimetry had a statistically significant greater overall survival (P=0.02). Thus we found that the routine use of dosimetry was associated with a lower brachytherapy dose, decreased complications, without any decrease in local control or survival.

The American Brachytherapy Society recommendations for low-dose-rate brachytherapy for carcinoma of the cervix

PURPOSE

This report presents guidelines for using low-dose-rate (LDR) brachytherapy in the management of patients with cervical cancer.

METHODS

Members of the American Brachytherapy Society (ABS) with expertise in LDR brachytherapy for cervical cancer performed a literature review, supplemented by their clinical experience, to formulate guidelines for LDR brachytherapy of cervical cancer.

RESULTS

The ABS strongly recommends that radiation treatment for cervical carcinoma (with or without chemotherapy) should include brachytherapy as a component. Precise applicator placement is essential for improved local control and reduced morbidity. The outcome of brachytherapy depends, in part, on the skill of the brachytherapist. Doses given by external beam radiotherapy and brachytherapy depend upon the initial volume of disease, the ability to displace the bladder and rectum, the degree of tumor regression during pelvic irradiation, and institutional practice. The ABS recognizes that intracavitary brachytherapy is the standard technique for brachytherapy for cervical carcinoma. Interstitial brachytherapy should be considered for patients with disease that cannot be optimally encompassed by intracavitary brachytherapy. The ABS recommends completion of treatment within 8 weeks, when possible. Prolonging total treatment duration can adversely affect local control and survival. Recommendations are made for definitive and postoperative therapy after hysterectomy. Although recognizing that many efficacious LDR dose schedules exist, the ABS presents suggested dose and fractionation schemes for combining external beam radiotherapy with LDR brachytherapy for each stage of disease. The dose prescription point (point A) is defined for intracavitary insertions. Dose rates of 0.50 to 0.65 Gy/h are suggested for intracavitary brachytherapy. Dose rates of 0.50 to 0.70 Gy/h to the periphery of the implant are suggested for interstitial implant. Use of differential source activity or loading minimizes excessive central dose rates. These recommendations are intended only as guidelines. The responsibility for medical decisions ultimately rests with the treating radiation oncologist.

CONCLUSION

Guidelines are suggested for LDR brachytherapy for cervical cancer. Practitioners and cooperative groups are encouraged to use these guidelines to formulate their treatment and dose-reporting policies.

Inter fraction variations in rectum and bladder volumes and dose distributions during high dose rate brachytherapy treatment of the uterine cervix investigated by repetitive CT-examinations

PURPOSE

To evaluate variation of dose to organs at risk for patients receiving fractionated high dose rate gynaecological brachytherapy by using CT-based 3D treatment planning and dose-volume histograms (DVH).

MATERIALS AND METHODS

Fourteen patients with cancer of the uterine cervix underwent three to six CT examinations (mean 4.9) during their course of high-dose-rate brachytherapy using radiographically compatible applicators. The rectal and bladder walls were delineated and DVHs were calculated.

RESULTS

Inter fraction variation of the bladder volume (CV(mean)=44.1%) was significantly larger than the inter fraction variation of the mean dose (CV(mean)=19.9%, P=0.005) and the maximum dose (CV(mean)=17.5%, P=0.003) of the bladder wall. The same trend was seen for rectum, although the figures were not significantly different. Performing CT examinations at four of seven brachytherapy fractions reduced the uncertainty to 4 and 7% for the bladder and rectal doses, respectively. A linear regression analysis showed a significant, negative relationship between time after treatment start and the whole bladder volume (P=0.018), whereas no correlation was found for the rectum. For both rectum and bladder a linear regression analysis revealed a significant, negative relationship between the whole volume and median dose (P<0.05).

CONCLUSION

Preferably a CT examination should be provided at every fraction. However, this is logistically unfeasible in most institutions. To obtain reliable DVHs the patients will in the future undergo 3-4 CT examinations during the course of brachytherapy at our institution. Since this study showed an association between large bladder volumes and dose reductions, the patients will be treated with a standardized bladder volume.

Intensity-modulated radiation therapy (IMRT) reduces small bowel, rectum, and bladder doses in patients with cervical cancer receiving pelvic and para-aortic irradiation

PURPOSE

The emergent use of combined modality approach (chemotherapy and radiation therapy) for the treatment of patients with cervical cancer is associated with significant gastrointestinal and genitourinary toxicity. Intensity-modulated radiation therapy (IMRT) has the potential to deliver adequate dose to the target structures while sparing the normal organs and could also allow for dose escalation to grossly enlarged metastatic lymph node in pelvic or para-aortic area without increasing gastrointestinal/genitourinary complications. We conducted a dosimetric analysis to determine if IMRT can meet these objectives in the treatment of cervical cancer.

METHODS AND MATERIALS

Computed tomography scan studies of 10 patients with cervical cancer were retrieved and used as anatomic references for planning. Upon the completion of target and critical structure delineation, the imaging and contour data were transferred to both an IMRT planning system (Corvus, Nomos) and a three-dimensional planning system (Focus, CMS) on which IMRT as well as conventional planning with two- and four-field techniques were derived. Treatment planning was done on these two systems with uniform prescription, 45 Gy in 25 fractions to the uterus, the cervix, and the pelvic and para-aortic lymph nodes. Normalization was done to all IMRT plans to obtain a full coverage of the cervix with the 95% isodose curve. Dose-volume histograms were obtained for all the plans. A Student's t test was performed to compute the statistical significance.

RESULTS

The volume of small bowel receiving the prescribed dose (45 Gy) with IMRT technique was as follows: four fields, 11.01 +/- 5.67%; seven fields, 15.05 +/- 6.76%; and nine fields, 13.56 +/- 5.30%. These were all significantly better than with two-field (35.58 +/- 13.84%) and four-field (34.24 +/- 17.82%) conventional techniques (p < 0.05). The fraction of rectal volume receiving a dose greater than the prescribed dose was as follows: four fields, 8.55 +/- 4.64%; seven fields, 6.37 +/- 5.19%; nine fields, 3.34 +/- 3.0%; in contrast to 84.01 +/- 18.37% with two-field and 46.37 +/- 24.97% with four-field conventional technique (p < 0.001). The fractional volume of bladder receiving the prescribed dose and higher was as follows: four fields, 30.29 +/- 4.64%; seven fields, 31.66 +/- 8.26%; and nine fields, 26.91 +/- 5.57%. It was significantly worse with the two-field (92.89 +/- 35.26%) and with the four-field (60.48 +/- 31.80%) techniques (p < 0.05).

CONCLUSION

In this dosimetric study, we demonstrated that with similar target coverage, normal tissue sparing is superior with IMRT in the treatment of cervical cancer.

Anorectal injury following pelvic radiotherapy

BACKGROUND

Current knowledge of the effects of radiation on the anorectum is based on a limited number of studies. Variability in delivery techniques, both currently and historically, combined with a paucity of prospective and randomized studies makes interpretation of the literature difficult. This review presents the existing evidence and identifies areas that require further work.

METHODS

This review is based on a literature search (Medline and PubMed) and manual cross-referencing.

RESULTS AND CONCLUSION

More than three-quarters of patients receiving pelvic radiotherapy experience acute anorectal symptoms and up to one-fifth suffer from late-phase radiation proctitis. About 5 per cent develop other chronic complications, such as fistula, stricture and disabling faecal incontinence. The risk of rectal cancer may be increased. Conservative treatment options are of limited value. Surgery may be considered if symptoms are severe, provided sphincter function is adequate and recurrent disease is excluded. Large prospective studies with accurate dosimetric data and long-term follow-up are needed to provide meaningful information on which to base new strategies to minimize the side-effects from radiotherapy.

High-dose-rate brachytherapy in the treatment of uterine cervix cancer. Analysis of dose effectiveness and late complications

PURPOSE

This retrospective analysis aims to report results of patients with cervix cancer treated by external beam radiotherapy (EBR) and high-dose-rate (HDR) brachytherapy.

METHODS AND MATERIALS

From September 1992 to December 1996, 138 patients with FIGO Stages II and III and mean age of 56 years were treated. Median EBR to the whole pelvis was 45 Gy in 25 fractions. Parametrial boost was performed in 93% of patients, with a median dose of 14.4 Gy. Brachytherapy with HDR was performed during EBR or following its completion with a dose of 24 Gy in four weekly fractions of 6 Gy to point A. Median overall treatment time was of 60 days. Patient age, tumor stage, and overall treatment time were variables analyzed for survival and local control. Cumulative biologic effective dose (BED) at rectal and bladder reference points were correlated with late complications in these organs and dose of EBR at parametrium was correlated with small bowel complications.

RESULTS

Median follow-up time was 38 months. Overall survival, disease-free survival, and local control at 5 years was 53.7%, 52.7%, and 62%, respectively. By multivariate and univariate analysis, overall treatment time up to 50 days was the only statistically significant adverse variable for overall survival (p = 0.003) and actuarial local control (p = 0.008). The 5-year actuarial incidence of rectal, bladder, and small bowel late complications was 16%, 11%, and 14%, respectively. Patients treated with cumulative BED at rectum points above 110 Gy(3) and at bladder point above 125 Gy(3) had a higher but not statistically significant 5-year actuarial rate of complications at these organs (18% vs. 12%, p = 0.49 and 17% vs. 9%, p = 0.20, respectively). Patients who received parametrial doses larger than 59 Gy had a higher 5-year actuarial rate of complications in the small bowel; however, this was not statistically significant (19% vs. 10%, p = 0.260).

CONCLUSION

This series suggests that 45 Gy to the whole pelvis combined with four fractions of 6 Gy to point A with HDR brachytherapy is an effective and safe fractionation schedule in the treatment of Stages II and III cervix cancer if realized up to 50 days. To decrease the small bowel complications, we decreased the superior border of the parametrial fields to the S2-S3 level and the total dose to 54 Gy.

Quantification of intracavitary brachytherapy parameters and correlation with outcome in patients with carcinoma of the cervix

PURPOSE

To quantify the M. D. Anderson criteria for acceptable implant geometry; to relate our system of intracavitary radiotherapy (ICRT) prescription to Manchester and ICRU reference doses; and to correlate these parameters with outcome measures.

METHODS AND MATERIALS

The relationships between intracavitary applicators and normal structures were measured directly from localization films of 808 applications performed in 396 patients who completed definitive treatment for cervical cancer between 1990 and 1994. The distances between applicators and tissue landmarks and the doses to Manchester and normal tissue reference points were correlated with outcome.

RESULTS

The median distance from the tandem to the sacrum was 4.0 cm, or one-third the distance from the pubis to the sacrum. The mean distance between the vaginal ovoids and cervical marker seeds was 7 mm, and the median distance between the tandem and the posterior edge of the ovoids was 50% of the ovoid length. In 92% of insertions, vaginal packing was posterior to or within 5 mm of a line that passed through the posterior edge of the ovoids, parallel to the tandem. The median doses to Point A and rectal, bladder, and vaginal surface reference points were 87 Gy, 68 Gy, 70 Gy, and 125 Gy, respectively. Although these reference doses were not routinely used to prescribe treatment, consistent applicator geometry and source selection resulted in a relatively narrow range of delivered doses. The average ratios between the doses at bladder or rectal reference points and Point A were somewhat greater when smaller vaginal applicators were used. Patients received a median of 5600 mgRaEq-h from ICRT. The total mgRaEq-h were correlated with but were not proportional to the dose at Point A. There were no significant correlations between the doses to standard reference points and the rates of central recurrence or major complications.

CONCLUSION

When ICRT implants are carefully placed, relatively high paracentral doses can be delivered that yield a high rate of central disease control with an acceptable rate of complications. The narrow range of doses delivered to standard reference points and their inconsistent correlation with the maximum doses delivered to normal tissues probably contributed to a lack of correlation between reference doses and outcome.

Colon pouch (Mainz pouch III) for continent urinary diversion after pelvic irradiation

OBJECTIVES

Urinary diversion after previous pelvic irradiation is challenging. The use of irradiated bowel in particular is associated with an increased rate of early and late complications. We therefore performed continent cutaneous urinary diversion using exclusively nonirradiated bowel segments in this group of patients.

METHODS

A continent colon pouch for urinary diversion was performed in 44 female patients after pelvic irradiation. The indications were irreparable vesical fistula in 20, local recurrence of gynecologic tumors in 22, and radical cystectomy for bladder cancer in 2 patients. Depending on the length of the nonirradiated bowel segment, a transverse-ascending colon pouch (n = 8) or transverse-descending colon pouch (n = 36) was performed. The efferent segment was created from a tapered bowel segment embedded in the pouch wall. The ureters were implanted using a submucosal (n = 67) or subserosal (n = 17) extramural tunnel.

RESULTS

No pouch-related complications were observed during the immediate postoperative period. In long-term follow-up (mean 52.2 months), upper urinary tract dilation was seen in five renal units. All five of these had been dilated preoperatively, and none required ureteral reimplantation. Incontinence occurred in 2 patients; both underwent reoperation with subsequent continence. Umbilical stoma stenosis was observed in 6 patients.

CONCLUSIONS

The technique of the colon pouch for continent urinary diversion in previously irradiated patients is safe and has a low complication rate. The use of nonirradiated bowel segments should be the method of choice in this group of patients.

Impact on treatment outcome and late effects of customized treatment planning in cervix carcinomas: baseline results to compare new strategies

PURPOSE

The aim of the study was to determine the predictive factors of complications, to evaluate the impact of customized treatment planning on late normal tissue effects per stage, and to report disease-free survival (DFS) and local control (LC) rates.

METHODS AND MATERIALS

From 1970 to 1994, 642 patients were treated with radiotherapy alone for carcinoma of the intact uterine cervix. According to the International Federation of Gynecology and Obstetrics (FIGO) substaging, 34% were Stage I, 39% Stage II, and 27% Stage III. The analysis was divided into three periods: 1970-1978 (use of standard prescriptions),1979-1984 (implementation of individual adjustments), 1985-1994 (systematic individual adjustments). Five-year DFS, LC, and complications rates were calculated using the Kaplan-Meier method. Predictive factors of complications were determined by univariate analysis using frequency tables and nonparametric t-tests. Multivariate analysis consisted of a polychotomous stepwise regression.

RESULTS

The comparison of the three time periods showed a significant reduction of the external radiation dose (dose above 40 Gy in 47% of patients before 1979 vs. 36% after 1984), of the use of parametrial boost (55% vs. 39%), of the use of vaginal cylinder (28% vs. 11.5%), and of the HWT volume (combined intracavitary and external irradiation) (842 cc vs. 503 cc on average). The total sequelae/complications rate, all toxicity grades, all stages, all organs was 51%. Five-year actuarial rate per toxicity grade was: G1, 42%; G2, 23.5%; G3, 10%; G4, 3%. The three main predictive factors for rectal and bladder sequelae/complications (all toxicity grades) taking into account time period were: the increase of external radiation dose, the high dose rate at reference points, and the whole vagina brachytherapy. No G4 occurred in the third period. The rate of G3 complications dropped from 16% to 6% over time: from 5% during the first period to 0% during the third period in Stage I, from 8% to 6% in Stage II, and from 23% to 12% in Stage III. G3 currently describes a variety of clinical situations with a different impact on quality of life which justifies further refinements of definitions of late effects. In our experience the severity of G3 markedly decreased: less than one-third of G3 had a real impact on quality of life in the last period compared to more than two-thirds in the first period. Meanwhile, 5-year LC rates remained stable in Stages I and II, 91% and 85% respectively. Conversely they fell from 75% to 55% in Stage III, thus raising the problem of underdosage and/or more accurate staging with time.

CONCLUSIONS

Customized treatment planning eradicated lethal complications and provided a significant decrease of G3 in all stages while maintaining high cure rates in early stages. Dose reduction should be considered with caution in Stage III.

[Contribution of imaging in radiotherapy planning in uterine cervix cancers]

External irradiation and brachytherapy are curative in the treatment of carcinoma of the cervix. The aim of radiotherapy is to optimize the irradiation of the target volume and to reduce the dose to critical organs. The use of imaging (computed tomography and magnetic resonance imaging added to clinical findings and standard guidelines) are studied in the treatment planning of external irradiation and brachytherapy in carcinoma of the cervix. Imaging allows an individualized and conformal treatment planning.

[Complications of treatments of invasive cancers of the uterine cervix with intact uterus: results and prevention]

The prospective record of acute and late toxicity after treatment of cervix carcinomas is a part of the description of treatment outcome as well as local control and survival. Due to the large number of scales and glossaries used, the comparison of the results from one study to another is often difficult. The French-Italian syllabus seems to be the most reliable scale, providing implementation of quality of life assessments. The main predictive factor of complications, which is not related to the treatment type, is the previous history of abdominal or pelvic surgery. The incidence and severity of complications occurring after surgery are related to the surgical procedure and to the amount of peri-uterine tissues removed. The increase in dose and volume of external irradiation and brachytherapy and the increase in dose rate of the low-dose rate brachytherapy are responsible for the radiotherapeutic morbidity. The significant decrease of severe complication rates during the last 15 years was obtained by the implementation of individual adjustments in treatment planning. The treatment strategies of early bulky and advanced carcinomas are changing. Concurrent radiotherapy and chemotherapy is becoming a standard, but its late toxicity needs to be documented by a longer follow-up. The optimisation of radiation therapy should remain a reference to evaluate the outcome and morbidity of the new combined strategies: the addition of chemotherapy will never compensate for less than optimal radiotherapy/brachytherapy planning.

[Curietherapy in uterine cervix cancers: what therapeutic trends?]

Brachytherapy is a fundamental step in the treatment of patients with cervical cancer. Brachytherapy allows a significant increase in the local control rate as well as the survival rate. Brachytherapy has to be performed as soon as possible after external irradiation in order to maintain the overall treatment time below 53 days. Technical and dosimetric data characterizing low dose-rate brachytherapy using ICRU 38 recommendations have led to an improvement in local control and a decrease in complications. Data are less well known for other dose rates. The role of interstitial brachytherapy is not clearly defined and its potential benefit is probably balanced by an increase in severe complications. Concomitant brachy-chemotherapy requires further clinical investigations, even if concomitant radio-chemotherapy has become a standard in advanced cervical cancers.