Tolerance of pelvic organs to radiation treatment for carcinoma of cervix

Lessons from radiochemotherapy and modern image-guided adaptive brachytherapy followed by hysterectomy

PURPOSE

To analyze the clinical outcomes and the safety of radiochemotherapy (RCT) and image-guided adaptive brachytherapy (IGABT) and to evaluate the impact of hysterectomy (HT) as completion of treatment for cervical cancer.

METHODS AND MATERIALS

145 patients with locally advanced cervical cancer were treated at our institution. Patients underwent RCT and IGABT, then hysterectomy (HT) as completion of treatment was performed, with the exception of patients with surgical contraindications, para aortic metastatic disease or patients who refused surgery. Clinical outcomes and morbidity were retrospectively reviewed in both groups. Local relapse free survival (LRFS), pelvic relapse free survival (PRFS) and overall survival (OS) were analyzed.

RESULTS

Completion HT was performed in 90 (62.1%) patients. Complete histological response and microscopic disease were found in 77 patients (85.6%). Local relapse was observed in 14 patients (9.6%) without differences between completion HT group and the definitive RCT and IGABT group (Odds Ratio OR = 1.73 [0.57-5.23], p = 0.33). The estimated 3-year LRFS and PRFS for the entire population were respectively 90% [84%-94%] and 93% [87%-96%], with no significant differences between them (respectively Hazard Ratio HR = 0.57 [0.20-1.64], p = 0.30 and HR = 0.37 [0.10-1.31], p = 0.12). The estimated 3-year OS rate for the whole population was 84% [75%-91%] with no significant differences between groups (HR = 0.81 [0.32-2.06], p = 0.65). Regarding morbidity, grade ≥ 2 vaginal toxicity was more frequent in the definitive RCT and IGABT group (43.6% vs 26.7%, p = 0.04). All grade 4 toxicity events were reported in the completion HT group.

CONCLUSIONS

Due to high severe toxicity, RCT and IGABT with dose escalation followed by completion hysterectomy don't seem compatible. No benefit and increased severe late morbidity were observed. Combined intracavitary/interstitial technique is mandatory in large target volume at brachytherapy.

Treatment of locally advanced carcinoma cervix with special emphasis on brachytherapy: A practice pattern survey among young radiation oncologist of India

BACKGROUND

Carcinoma cervix is one of the two most common cancers of Indian women with very high morbidity and mortality burden. Although India probably is the leading country in numbers patients of cervix treated radically with combination of teletherapy and brachytherapy (BT), there is presumed diversity of practice across the country due to the inequality of available infrastructure, absence of uniform the training of the radiation oncologists, and absence of any national guidelines. The present survey was conducted to determine current practice patterns in management of locally advanced carcinoma cervix with regard to gynecologic high-dose-rate among the radiation oncologist across the country.

METHODOLOGY

A 25-item survey was undertaken to study the standard management pattern of Stage IIB-IIIB cervical cancer with special emphasis on the BT practice patterns among various young radiation oncologist working across the country. The survey was undertaken in person in the form of interview questionnaire among the younger members of association of radiation oncologist of India during two national conferences, along with telephonic interview of other members as obtained from the national directory.

RESULTS

About 57 young radiation oncologists from 57 centers across the country were surveyed. 25 of them represented private nonacademic centers, 24 represented government academic centers, the rest were from private academic, nongovernmental organization (NGO) run and other centers. The most common teletherapy dose prescribed was 46 Gy/23# for Stage II, and50 Gy/25 # for Stage III disease. HDR after loader with 192Ir is the most common machine (82.6%) in use and computed tomography scan is the most commonly (30/57) used imaging for planning. The most common intracavitary dose pattern for all stages was 7 Gy × 3 fractions (30/57s) and 9 Gy × 2 (12/57) fractions. Although in most centers, computed tomography-based delineation of organs at risk is done routinely; however, target volume delineation and dose prescription/optimization for the same is routinely done in handful of centers (5/57). The mean planned dose to Point A for combined external-beam radiation and BT (EQD210) was about 77.5 Gy for Stage IIIB and 72.6 Gy for Stage II disease.

CONCLUSION

Although fractionation patterns may vary, the overall mean dose administered for cervical cancer is similar across the country, which is slightly lower than the recommended doses as per stage by various international guidelines.

A comparative study of two reconstructive methods and different recommendations in intracavitary brachytherapy

Purpose

Intracavitary brachytherapy (ICB) is a widely used technique in the treatment of cervical cancer. In our Institute, we use different reconstructive methods in the conventional planning procedure. The main aim of this study was to compare these methods using critical organ doses obtained in various treatment plans. There is a small difference in the recommendations in selecting bladder dose point between ICRU (International Commission on Radiation Units & Measurements) -38 and ABS (American Brachytherapy Society). The second objective of the study was to find the difference in bladder dose using both recommendations.

Material and methods

We have selected two methods: variable angle method (M1) and orthogonal method (M2). Two orthogonal sets of radiographs were taken into consideration using conventional simulator. All four radiographs were used in M1 and only two radiographs were used in M2. Bladder and rectum doses were calculated using ICRU-38 recommendations. For maximum bladder dose reference point as per the ABS recommendation, 4 to 5 reference points were marked on Foley’s balloon.

Results

64% of plans were showing more bladder dose and 50% of plans presented more rectum dose in M1 compared to M2. Many of the plans reviled maximum bladder dose point, other than ICRU-38 bladder point in both methods. Variation was exceeded in 5% of considerable number of plans.

Conclusions

We observed a difference in critical organ dose between two studied methods. There is an advantage of using variable angle reconstruction method in identifying the catheters. It is useful to follow ABS recommendation to find maximum bladder dose.

Is there a limit to dose escalation for rectal cancer?

The radiation tolerance of the rectum is not fully understood. Published studies on the radiation treatment of cancers of the prostate, cervix and rectum have been reviewed to determine currently recommended dose-volume guidelines. The need for further studies directed specifically at the treatment of primary rectal cancer and perirectal node metastases is discussed. There seems to be room for escalation of the external beam doses currently given.

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.

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.

Laparoscopically assisted radical vaginal hysterectomy vs. radical abdominal hysterectomy for cervical cancer: a match controlled study

OBJECTIVES

The technical feasibility of laparoscopically assisted radical vaginal hysterectomy has been well described, but its advantages over the open technique remain largely unproven. We reviewed and compared our experiences with both approaches.

METHODS

All patients undergoing laparoscopically assisted radical vaginal hysterectomy (LARVH) between 1996 and 2003 were identified and matched for age, FIGO stage, histological subtype and nodal metastases using a control group of women who underwent radical abdominal hysterectomy (RAH) during the same time period.

RESULTS

Fifty-seven women were listed for LARVH, resulting in five conversions. Fifty cases were matched successfully using the criteria above. The majority of cases were FIGO stage 1B1. Statistically significant differences (P < 0.05) were present when the following were compared for LARVH vs. RAH: duration of surgery (median 180 vs. 120 min), blood loss (median 350 vs. 875 ml), hospital stay (median 5 days vs. 8 days) and duration of continuous bladder catheterisation (median 3 days vs. 7 days). There were no statistically significant differences with regard to nodal yield, completeness of surgical margins or perioperative complication rate. Four major complications (8%, three cystotomies and one enterotomy) occurred in the LARVH group and three in the RAH group (6%, one pulmonary embolism, one ureteric injury and one major haemorrhage). Three women in LARVH group had seen a specialist regarding postoperative bladder dysfunction, versus 12 in the RAH group (P = 0.04). No patients in the LARVH group reported constipation requiring regular laxatives, versus six in the RAH group (P = 0.03). Median follow-up was 52 months for LARVH and 49 months for RAH. There was no significant difference between recurrence rates or overall survival (94% for LARVH vs. 96% for RAH).

CONCLUSIONS

Despite the inherent limitations of LARVH and its associated learning curve, the procedure conveys many advantages over the open technique in terms of blood loss, transfusion requirement and hospital stay. In addition, the incidence of postoperative bladder and bowel dysfunction appears low-suggesting improved quality of life-without compromising survival.