Early toxicity and treatment outcomes of extended field-intensity modulated radiotherapy for cervical cancer patients with para-aortic nodal metastasis

Improvement in radiation techniques for locally advanced cervical cancer during the last two decades

Since the National Cancer Institute (NCI) alert of concurrent chemoradiotherapy, radiotherapy has been changed from external beam radiotherapy plus brachytherapy to platinum-based concurrent chemoradiotherapy. Therefore, concurrent chemoradiotherapy plus brachytherapy has become a standard treatment for locally advanced cervical cancer. Simultaneously, definitive radiotherapy has been changed gradually from external beam radiotherapy plus low-dose-rate intracavitary brachytherapy to external beam radiotherapy plus high-dose-rate intracavitary brachytherapy. Cervix cancer is uncommon in developed countries; hence, international collaborations have been critical in large-scale clinical trials. The Cervical Cancer Research Network (CCRN), created from the Gynecologic Cancer InterGroup (GCIG), has investigated various concurrent chemotherapy regimens and sequential methods of radiation and chemotherapy. Most recently, many clinical trials of combining immune checkpoint inhibitors with radiotherapy have been ongoing for sequential or concurrent settings. During the last decade, the method of standard radiation therapy has changed from three-dimensional conformal radiation therapy to intensity-modulated radiation therapy for external beam radiotherapy and from two-dimensional to three-dimensional image-guided approaches for brachytherapy. Recent improvements include stereotactic ablative body radiotherapy and MRI-guided linear accelerator (MRI-LINAC) using adaptive radiotherapy. Here we review the current progress of radiation therapy during the last two decades.

Impact of Adapted Radiotherapy Schedules on Bowel Sparing in Node-Positive Cervical Cancer

PURPOSE

Definitive radiation therapy (RT) for locally advanced node-positive cervical cancer confers significant toxicity to pelvic organs including the small bowel. Gross nodal disease exhibits significant shrinkage during RT, and yet conventional RT does not account for this change. We evaluated the reduction in absorbed bowel dose using various adaptive RT schedules.

METHODS AND MATERIALS

We obtained 130 evaluable scans (computed tomography simulation and 25 cone beam computed tomography scans per patient) of 5 patients who had received definitive external beam RT for lymph node positive cervical cancer daily over 5 weeks. Using a single universal volumetric modulated arc therapy plan with predefined optimization priorities, we created adapted RT plans in 4 schedules: Daily, Weekly, Twice, and NoAdapt (mimicking conventional nonadapted RT). The in silico (computer modeled) patients were treated to 45 Gy to primary cervical disease with a simultaneous integrated boost to 55 Gy to involved lymph nodes. We evaluated dose metrics including D2cc, D15cc, and V45 to determine the impact of adapted RT schedules on bowel sparing. Statistical tests included the Student t test, analysis of variance, and the Spearman rank correlation.

RESULTS

The quantity of reduced bowel dose was significantly associated with the chosen planning schedule in all evaluated metrics and was proportional to the frequency of adaptive RT with significant moderate-to-strong monotonicity. Both D2cc and D15cc were reduced an average of 2.7 Gy using daily replanning compared with a nonadapted approach. A minimally adapted strategy of only 2 replans also confers a significant dosimetric benefit over a nonadapted approach. Reduced standard deviations of D2cc and V45 bowel doses over the treatment courses were significantly associated with the choice of planning schedule with strong monotonicity.

CONCLUSIONS

All adaptive RT schedules evaluated confer significant dosimetric advantages in bowel sparing over a conventional nonadapted technique, with greater sparing seen with more frequent replanning schedules. These findings warrant future trials of adaptive RT for pelvic malignancies.

Overall Severe Morbidity After Chemo-Radiation Therapy and Magnetic Resonance Imaging-Guided Adaptive Brachytherapy in Locally Advanced Cervical Cancer: Results From the EMBRACE-I Study

PURPOSE

To evaluate overall severe late morbidity (grade ≥3) in patients with locally advanced cervical cancer treated with chemo-radiation therapy and magnetic resonance image guided adaptive brachytherapy within the prospective EMBRACE-I study, and to compare the results with published literature after standard radiograph based brachytherapy (BT).

METHODS AND MATERIALS

From 2008 to 2015 the EMBRACE-I study enrolled 1416 patients. Morbidity was assessed (Common Terminology Criteria for Adverse Events version 3.0) every 3 months the 1st year, every 6 months the second and third year, and yearly thereafter and 1251 patients had available follow-up on late morbidity. Morbidity events (grade 3-5) were summarized as the maximum grade during follow-up (crude incidence rates) and actuarial estimates at 3 and 5 years. To compare with the published literature on standard radiograph based BT, Common Terminology Criteria for Adverse Events scores from the EMBRACE-I study were retrospectively converted into a corresponding score in the Radiation Therapy Oncology Group and European Organization for Research and Treatment of Cancer system.

RESULTS

In total, 534 severe events occurred in 270 patients; 429 events were grade 3 and 105 were grade 4 events. Actuarial estimates for grade ≥3 gastrointestinal (GI), genitourinary (GU), vaginal and fistula events at 5 years were 8.5% (95% confidence interval [CI], 6.9%-10.6%), 6.8% (95% CI, 5.4%-8.6%), 5.7% (95% CI, 4.3%-7.6%), and 3.2% (95% CI, 2.2%-4.5%), respectively. The 5-year actuarial estimate for organ-related events (GI, GU, vaginal, or fistula) was 18.4% (95% CI, 16.0%-21.2%). The 5-year actuarial estimate when aggregating all G≥3 endpoints (GI, GU, vaginal, fistulas, and non-GI/GU/vaginal) was 26.6% (95% CI, 23.8%-29.6%). Thirteen patients had a treatment-related death, 8 of which were associated with GI morbidity.

CONCLUSIONS

This report assesses severe morbidity from the largest prospective study on chemo-radiation therapy and image guided adaptive brachytherapy for locally advanced cervical cancer to date. Severe late morbidity was limited per endpoint and organ category, but considerable when aggregated across organs and all endpoints. The late morbidity results in the EMBRACE-I study compare favorably with published literature on standard radiograph based BT for GI morbidity, vaginal morbidity, and fistulas.

The impact of para-aortic lymph node irradiation on disease-free survival in patients with cervical cancer: a systematic review and meta-analysis

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Standard of care of locally advanced cervical cancer is based on concurrent chemoradiotherapy.

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Para-aortic radiotherapy (PAO-RT) has become controversial in the chemotherapy era.

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Systematic review on impact of PAO-RT on disease-free survival yielded 11 studies.

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Meta-analysis of 3 studies showed pooled adjusted HR of 0.87 (95% CI: 0.79–0.97).

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Findings support further investigation in prospective controlled trials.

Background

Patients with locally advanced cervical cancer without para-aortic lymph node metastases (PAO-LNM) at diagnosis who undergo concurrent chemoradiotherapy are at 4–11% risk of developing PAO-LNM during follow-up. Some studies suggest a beneficial influence of elective para-aortic radiotherapy (PAO-RT) on disease-free survival (DFS) in these patients. The aim of this study was to systematically review and meta-analyse literature on the impact of PAO-RT on DFS in cervical cancer patients.

Methods

A systematic search of PubMed/MEDLINE and EMBASE databases was performed. The analysis included intervention studies that reported on DFS in patients with cervical cancer who received chemotherapy and pelvic radiotherapy with or without PAO-RT. From each included study, relevant study characteristics and outcome data including the hazard ratio (HR) adjusted for potential confounders were extracted. An overall pooled adjusted hazard ratio (aHR) for DFS after PAO-RT versus no PAO-RT was calculated using a random-effects model.

Results

A total of 2,016 articles were evaluated. Eleven articles were included in the systematic review, of which 3 were appropriate for quantitative meta-analysis. Pooling of these 3 cohorts (including 1,113 patients) demonstrated a statistically significant association between PAO-RT and DFS (pooled aHR 0.87, 95% confidence interval: 0.79–0.97). No significant heterogeneity among reported aHRs was observed (I² = 0.0%).

Conclusions

This meta-analysis suggests a modest but significant beneficial impact of elective para-aortic radiotherapy on DFS in patients with locally advanced cervical cancer who undergo concurrent chemoradiotherapy. This finding based on non-randomized studies provides an imperative for further investigation in prospective controlled trials.

Treatment Strategies and Prognostic Factors of 2018 FIGO Stage IIIC Cervical Cancer: A Review

Cervical cancer is the fourth most common malignant tumor globally in terms of morbidity and mortality. The presence of lymph node metastasis (LNM) is an independent prognostic factor for progression-free survival (PFS) and overall survival (OS) in cervical cancer patients. The International Federation of Gynecology and Obstetrics (FIGO) staging system was revised in 2018. An important revision designates patients with regional LNM as stage IIIC, pelvic LNM only as stage IIIC1, and para-aortic LNM as stage IIIC2. However, the current staging system is only based on the anatomical location of metastatic lymph nodes (LNs). It does not consider other LN status parameters, which may limit its prognostic significance to a certain extent and needs further exploration and confirmation in the future. The purpose of this review is to summarize the choice of treatment for stage IIIC cervical cancer and the effect of different LN status parameters on prognosis.

Validation and applicability of para-aortic lymph nodal contouring atlas in cervical cancer

BACKGROUND AND PURPOSE

CTV delineation guidelines for the para-aortic nodal region for patients with cervical cancer have been proposed (Keenan et al., 2018). The purpose of this study was to validate these guidelines with the use of CT datasets of cervical cancer patients with macroscopic PALN treated with definitive (chemo)radiation (CTRT) at our center.

MATERIALS AND METHODS

Planning CT datasets of 71 cervical cancer patients with gross PA nodal disease treated with EFRT were used. Two hundred and two PALN were identified based on size and morphology on diagnostic CECT, PET CT, or histologically proven PALN. LN regions were divided into upper, middle, and lower and based on their relation to the aorta and IVC. Macroscopic PALN were contoured, and the CTV for PALN irradiation was generated based on the proposed guidelines on ECLIPSE (Version 13.5). The centre of mass (COM_N) was calculated for each gross PALN. The evaluation was done to review the presence of COM_N in relation to the CTV PALN.

RESULTS

The most common location of PALN was Left para-aortic (105 LN-52%), Aortocaval (55 LN-27.2%), and Precaval (14 LN-6.9%). Lower PALN were the commonest (104 LN-51.5%). Ninety-three were middle PALN (46%), and 5 were upper PALN (2.5%). After excluding upper PALN, COM_N for 11 PALN (5.5%) were outside the CTV while 20 were junctional.

CONCLUSION

Our study shows that more than 95% of PALN in this patient cohort were covered using these guidelines with the addition of an extra 5 mm margin laterally on the left.

Pretreatment Squamous Cell Carcinoma Antigen (SCC-Ag) as a Predictive Factor for the Use of Consolidation Chemotherapy in Cervical Cancer Patients After Postoperative Extended-Field Concurrent Chemoradiotherapy

Objective: The goal of this study was to confirm the clinical value of pretreatment serum squamous cell carcinoma antigen (SCC-Ag) in the administration of consolidation chemotherapy in patients with cervical cancers undergoing postoperative extended-field radiotherapy (EFRT) and concurrent chemotherapy (CCRT). Methods: Between 2007 and 2018, a total of 113 patients were treated with postoperative extended-field intensity-modulated radiotherapy (EF-IMRT) and CCRT. There were 63 patients receiving extended-field concurrent chemoradiotherapy (EF-CCRT) and consolidation chemotherapy, while another 50 patients underwent EF-CCRT alone. For the planning target volume, the prescribed dose was 45 to 50.4Gy/25 to 28 fractions. The consolidation chemotherapy regimen contained docetaxel and cisplatin. Results: For the patients with high pretreatment SCC-Ag, the addition of consolidation chemotherapy significantly improved their treatment outcomes and they had better 5-year overall survival (OS) (81.02% vs 63.44%, P = .018) and disease-free survival (DFS) (76.95% vs 61.12%, P = .007) than those without it. Meanwhile, the patients with consolidation chemotherapy had a lower rate of distant metastasis (8.8% vs 34.8%, P = .001). For the patients with low pretreatment SCC-Ag, there was no difference in prognosis between patients receiving consolidation chemotherapy and those not receiving consolidation. In multivariate analysis, consolidation chemotherapy was found to be a factor significantly associated with DFS (P = .035, 95% confidence interval (CI): 0.304-0.977) and distant metastasis (P = .009, 95% CI: 0.125-0.841). Conclusion: The patients who received consolidation chemotherapy showed significantly better DFS. Furthermore, pretreatment serum SCC-Ag > 6.5 ng/mL may be a predictive factor for the use of consolidation chemotherapy in cervical cancer patients treated with postoperative EF-CCRT.

Radiation-Induced Emesis (RIE) in Extended-Field Radiotherapy for Gynecological Malignancies: Dosimetric and Non-Dosimetric Factors

Radiation-induced emesis (RIE) is usually noted during abdominal-pelvic radiotherapy. In gynecological malignancies, it is usually noted in para-aortic but not whole-pelvic irradiation. Irradiated small bowel (SB) may be associated with RIE. The significance of SB dosimetry remains unclear. Dosimetric and non-dosimetric factors were evaluated and correlated with RIE in 45 patients with gynecological malignancies undergoing extended-field radiotherapy (EFRT) (median 45 Gy) from 2006 to 2021. Early-onset RIE (within 72 h after the first fraction of EFRT) was noted in 10 of 12 RIE patients. RIE was significantly associated with the SB mean dose. The RIE rates were 58.3% and 15.2% (p = 0.007) in patients with a low (<63%) and high (≥63%) SB mean dose. Logistic regression revealed that the SB mean dose remained the independent factor of overall RIE (p = 0.049) and early-onset RIE (p = 0.014). Therefore, constraint of the SB mean dose limited to less than 63% of the prescribed dose is suggested to decrease RIE.

Intensity modulated radiotherapy in carcinoma cervix with metastatic para-aortic nodes: an institutional experience from a Regional Cancer Centre of Eastern India

Background

Cervical cancer is a major health problem, especially in developing countries like India. Extended field radiotherapy (EFRT) for cancer cervix treatment remains a challenging task for radiation oncologists. In the last decade studies have shown that EFRT using intensity modulated radiotherapy (IMRT) is feasible in treating gynaecological malignancies but there is a dearth of literature on this specific topic from this part of the world where patient profile differs greatly in several aspects from that of the western world. The aim of the study was evaluation of treatment response and toxicity profile in cases of carcinoma cervix with metastatic para-aortic nodes treated with intensity modulated radiotherapy technique.

Materials and methods

In this retrospective study the treatment records of 45 para-aortic node positive cervical cancer patients treated with EFRT (IMRT) and concurrent cisplatin were analysed for evaluation of loco-regional control and toxicities.

Results

Forty-four patients received full course of treatment. Among those 44 patients, 93.2% achieved complete response. Overall, the treatment was tolerated well and toxicities were within acceptable limits. Acute grade 3–4 toxicities were observed mostly in the form of anaemia and leucopenia. Most common late toxicities were those of small and large intestine.

Conclusion

EFRT with concurrent chemotherapy was successfully delivered for para-aortic nodes positive cervical cancer patients in Indian scenario where under-nutrition, infection, anaemia and several other factors adversely influence treatment outcome. Pelvic and para-aortic control rates were satisfactory. The technique was associated with an acceptable acute and late toxicity profile.