Clinical Outcome of Adjuvant Treatment of Endometrial Cancer Using Aperture-Based Intensity-Modulated Radiotherapy

Outcome and safety analysis of endometrial cancer patients treated with postoperative 3D-conformal radiotherapy or intensity modulated radiotherapy

BACKGROUND

We sought to analyze the toxicity rates and the treatment outcomes in endometrial cancer (EC) patients treated with postoperative three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT).

MATERIAL AND METHODS

The clinical data of 646 EC patients treated with postoperative adjuvant 3DCRT (265 patients, 41%) or with IMRT (381 patients, 59%) between April 2007 and August 2019 were retrospectively analyzed. The primary endpoints were treatment-related acute and late gastrointestinal (GI) and genitourinary (GU) toxicities. The secondary endpoints were LC and overall survival (OS) and disease-free survival (DFS).

RESULTS

Median follow-up time was 37 months. The rates for acute GI and GU toxicities of any grade for the entire group were 55.6% and 46.8%, respectively. Acute grade ≥2 GI toxicity was significantly less in patients treated with IMRT compared to those treated with 3DCRT (11.0% vs. 19.2%, p=.004). However, no significant difference grade ≥2 GU toxicities was observed between the 3DCRT and IMRT groups (15.1% vs. 11.0%; p=.15). Acute grade ≥2 GI and GU toxicities were higher in patients receiving systemic chemotherapy, while paraaortic field irradiation increases only the risk of acute grade ≥2 GI toxicity. Estimated 3-year late grade ≥3 GI toxicity rates in the 3DCRT- and IMRT-treated patients were 4.6% and 1.9% (p= .03), respectively. The patients treated with adjuvant ChT had higher rates of late serious GI complications than those without adjuvant ChT. No significant difference in terms of survival and disease control was observed between the 3DCRT and IMRT treatment groups. No significant factor for LC was found in the multivariate analysis.

CONCLUSION

In this multicentric study involving one of largest patient population, we found that IMRT-treated EC patients showed comparable clinical outcomes but with a lower incidence of GI toxicities compared with those treated with 3DCRT.

Comparison of 3D conformal radiation therapy and intensity-modulated radiation therapy in patients with endometrial cancer: efficacy, safety and prognostic analysis

Introduction: Adjuvant whole-pelvic radiation therapy (WPRT) improves locoregional control for high-intermediate stages I-III endometrial cancer patients. Intensity modulated radiation therapy (IMRT) tends to replace the standard 3D conformal radiation therapy (3DCRT) technique used in trials. Material and methods: Consecutive patients with stages I-IIIc endometrial cancer treated between 2008 and 2014 in our department with post-operative 3DCRT or IMRT WPRT were studied retrospectively. Patients with cervical involvement underwent additional low-dose rate vaginal brachytherapy. The impact of the WPRT technique on local control, tolerance, disease-free survival (DFS) and overall survival (OS) was assessed. Clinicians evaluated routinely acute radiation toxicity each week during radiation therapy and late toxicity during standard follow-up consultations. Results: Median follow-up was 50 months (range: 6-158). Among the 83 patients included, 47 were treated with 3DCRT and 36 with IMRT. There was no difference in patient characteristics between groups. The 5-year locoregional control and DFS rates were 94.5% and 68%, respectively. No significant difference was found between the 3DCRT and IMRT groups in terms of survival, with 5-year OS rates of 74.6% and 78%, respectively. In multivariate analysis, age over 68, stage > T1 and grade 3 were independently associated with shorter DFS and OS. Seven patients (8.4%) had grades 3-4 acute gastrointestinal (GI) toxicity with five patients (10.6%) and two (5.4%) in the 3DCRT and IMRT groups, respectively (p = .69). One case (1.2%) of late grade 3 GI toxicity was observed treated in 3DCRT. Conclusions: IMRT seems to be a safe technique for the treatment of endometrial cancer with a trend towards decreased acute GI toxicities. Results of the phase 3 RTOG 1203 trial are needed to confirm these results.

Optimization of re-irradiation using deformable registration: a case study

Re-irradiation is frequently performed in radiotherapy (RT) departments. We present an optimization methodology that takes the previous irradiation into account. A 68-year-old female patient suffering from rectal adenocarcinoma, who had previously undergone RT for metastases to the right iliac bone, presented with a recurrence of metastasis to the L5 and the left sacroiliac joint. Re-irradiation was performed using volumetric modulated arc therapy (VMAT). We proceeded to a registration of the previous RT planning CT and RT doses to the new planning CT. Virtual volumes corresponding to the intersection of the small bowel (SB) and each isodose structure were created. We calculated the maximal dose (D_max) that each virtual structure could receive and considered them as constraints. We called this technique modified VMAT. We compared this technique with a standard VMAT plan and a three-dimensional RT plan. Using the modified VMAT technique, a total dose of 20 Gy in five fractions of 4 Gy was delivered to the planning target volume without any acute toxicity. A composite dosimetry was realized with each technique to compare the dose given to the already irradiated SB. We calculated the D_max received by the already irradiated SB in equivalent dose of 2 Gy fractions. The Dmax was 46.8, 60 and 52 Gy for modified VMAT, standard VMAT and three-dimensional RT, respectively. Dose deformation was used to create new constraint structures to optimize the dose delivered to surrounding tissues. This methodology is readily feasible in clinical routine to optimize the re-irradiation process.

Para-aortic and pelvic extended-field radiotherapy for advanced-stage uterine cancer: dosimetric and toxicity comparison between the four-field box and intensity-modulated techniques

BACKGROUND

In patients with advanced-stage endometrial carcinoma (eca), extended-field radiotherapy (efrt) is traditionally delivered by the 3-dimensional conformal (3d-crt) 4-field box technique. In recent years, the use of intensity-modulated radiotherapy (imrt) in gynecologic cancers has increased. We compared the delivery of efrt by the 3d-crt and contemporary imrt techniques.

METHODS

After surgical staging and adjuvant chemotherapy in 38 eca patients, efrt was delivered by either imrt or 3d-crt. Doses to the organs at risk, side effects, and outcomes were compared between the techniques.

RESULTS

Of the 38 eca patients, 33 were stage iiic, and 5 were stage ivb. In the imrt group, maximal doses to rectum, small intestine, and bladder were significantly higher, and mean dose to bladder was lower (p < 0.0001). Most acute gastrointestinal, genitourinary, and hematologic side effects were grade i or ii and were comparable between the groups. In long-term follow-up, only grade 1 cystitis at 3 months was statistically higher in the imrt patients. No grade iii or iv gastrointestinal or genitourinary toxicities were observed. No statistically significant differences in overall and disease-free survival or recurrence rates were observed between the techniques.

CONCLUSIONS

In advanced eca patients, imrt is a safe and effective technique for delivering efrt to the pelvis and para-aortic region, and it is comparable to the 3d-crt 4-field box technique in both side effects and efficacy. For centres in which imrt is not readily available, 3d-crt is a valid alternative.

Safety of adjuvant intensity-modulated postoperative radiation therapy in endometrial cancer: Clinical data and dosimetric parameters according to the International Commission on Radiation Units (ICRU) 83 report

AIM

To report a single-institution experience using postoperative pelvic Intensity Modulation Radiation Therapy (IMRT) using tomotherapy accelerators (TA) in postoperative endometrial cancer (EC) regarding ICRU 83 recommendations.

BACKGROUND

IMRT in gynecological malignancies provides excellent dosimetric data, lower rates of adverse events and clinical data similar to historical series.

MATERIAL AND METHODS

Seventy-six patients with EC were postoperatively treated with adjuvant IMRT using TA. The IMRT dose was 45 Gy for patients without positive lymph nodes and Type I histology and 50.4 Gy for patients with positive lymph nodes and/or type II histology.

RESULTS

With a median follow-up of 29 months, the 12- and 24-month Overall Survival (OS) and Disease-Free Survival (DFS) were 96%, 93%, 87%, and 74%, respectively. Age of less than 60 years was associated with better OS (HR: 8.9; CI: 1.1-68) and DFS (HR: 3.5; CI: 1.2-10.2). Patients with Type II and Type I Grade III histology had a worse OS (HR: 3.3; CI: 1.1-11). Five women (6.6%) presented in-field local vaginal recurrence, 2 (2.6%) presented non-in-field vaginal recurrence, 4 (5.2%) presented pelvic node and distant recurrence and 11 (14.4%) presented only distant metastases. One patient stopped radiation treatment due to Grade III acute diarrhea. No Grade III late toxicity was observed. Planning Target Volume (PTV) coverage showed mean D2, D50, D95, and D98 of 51.64-46.23 Gy, 49.49-44.97 Gy, 48.62-43.96 Gy, and 48.47-43.58 Gy for patients who received 45 and 50.4 Gy, respectively.

CONCLUSIONS

IMRT with TA in postoperative EC shows excellent conformity and homogeneity of PTV dose. Without Grade III late toxicity, data from this cohort demonstrated the utility of IMRT.

[Evidence based medicine and high performance irradiation techniques: endometrial cancer]

Radiation oncology is a field in which many technologic improvements have been made over the past decades. External beam radiotherapy has evolved from treatment fields planned on X-rays to 3-dimensional planning with fusion with MRI's and PET images. Recently, intensity-modulated radiotherapy has been tested for many cancer localizations, and its role in the treatment of gynecologic cancers is still under evaluation. Potential benefits are well known: decrease of treatment toxicity, improvement of efficacy through better dose delivery. But the implementation of this technique requires a careful target and organs at risk delineation. The goal of this review is to evaluate the use of intensity-modulated radiotherapy in endometrial cancers with respect of dosimetric and clinical studies to date. In addition, challenges and perspectives of intensity-modulated radiotherapy integration are discussed.

Clinical outcomes of image guided radiation therapy (IGRT) with gold fiducial vaginal cuff markers for high-risk endometrial cancer

OBJECTIVE

To report two year clinical outcomes of image guided radiation therapy (IGRT) to the vaginal cuff and pelvic lymph nodes in a series of high-risk endometrial cancer patients.

METHODS

Twenty-six consecutive high-risk endometrial cancer patients requiring adjuvant radiation to the vaginal cuff and regional lymph nodes were treated with vaginal cuff fiducial-based IGRT. Seventeen (65%) received sequential chemotherapy, most commonly with a sandwich technique. Brachytherapy followed external radiation in 11 patients to a median dose of 18 Gy in 3 fractions. The median external beam dose delivered was 47.5 Gy in 25 fractions.

RESULTS

All 656 fractions were successfully imaged and treated. The median overall translational shift required for correction was 9.1 mm (standard deviation, 5.2 mm) relative to clinical set-up with skin tattoos. Shifts of 1 cm, 1.5 cm, and 2 cm or greater were performed in 43%, 14%, and 4% of patients, respectively. Acute grade 2 gastrointestinal (GI) toxicity occurred in eight patients (30%) and grade 3 toxicity occurred in one. At two years, there have been no local or regional failures and actuarial overall survival is 95%.

CONCLUSION

Daily image guidance for high-risk endometrial cancer results in a low incidence of acute GI/genitourinary (GU) toxicity with uncompromised tumor control at two years. Vaginal cuff translations can be substantial and may possibly result in underdosing if not properly considered.

Postoperative pelvic intensity-modulated radiotherapy in high risk endometrial cancer

OBJECTIVE

According to national surveys, the use of intensity-modulated radiation therapy (IMRT) in gynecologic cancers is on the rise, yet there is still some reluctance to adopt adjuvant IMRT as standard practice. The purpose of this study is to report a single-institution experience using postoperative pelvic IMRT with or without chemotherapy in high-risk endometrial cancer.

METHODS

From 11/2004 to 12/2009, 46 patients underwent hysterectomy/bilateral salpingo-oophorectomy for stage I-III (22% stage I/II and 78% stage III) endometrial cancer. Median IMRT dose was 50.4Gy. Adjuvant chemotherapy was given to 30 (65%) patients.

RESULTS

With a median follow-up of 52months, 4 patients recurred: 1 vaginal plus lung metastasis, 2 isolated para-aortic recurrences, and 1 lungs and liver metastasis. Five-year relapse rate was 9% (95% CI, 0-13.6%). Five-year disease-free survival (DFS) was 88% (95% CI, 77-98%) and overall survival (OS) was 97% (95% CI, 90-100%). There were 2 patients with non-hematological grade 3 toxicity: 1 (2%) acute and 1 (2%) chronic gastrointestinal toxicity. In patients treated with IMRT and chemotherapy (n=30), 5 had grade 3 leukopenia, 8 grade 2 anemia, and 2 grade 2 thrombocytopenia.

CONCLUSIONS

Oncologic outcomes with postoperative IMRT were very good, with DFS and OS rates of >88% at median follow-up of 52months, despite a preponderance (78%) of stage III disease. Toxicity was minimal even in the setting of an aggressive trimodality (65% of patients) approach. Data from this study and emerging data from RTOG trial 0418 demonstrate the advantages of IMRT in high-risk endometrial cancer.

Helical tomotherapy provides efficacy similar to that of intensity-modulated radiation therapy with dosimetric benefits for endometrial carcinoma

Background

The purpose of this study was to compare the efficacy of intensity-modulated radiotherapy (IMRT) and helical tomotherapy for endometrial cancer.

Methods

Between November 1, 2006 and November 31, 2010, 31 patients with histologically confirmed endometrial cancer were enrolled. All enrolled patients received total abdominal hysterectomy and bilateral salpingo-oophorectomy with adjuvant whole pelvic IMRT or helical tomotherapy.

Results

The actuarial 3-year overall survival, disease-free survival, locoregional control, and distant metastasis-free rates for the IMRT and helical tomotherapy groups were 87.5% versus 100%, 91.7% versus 51.7%, 91.7% versus 83.3%, and 91.7% versus 51.7%, respectively. The conformal index and uniformity index for IMRT versus helical tomotherapy was 1.25 versus 1.17 (P = 0.04) and 1.08 versus 1.05 (P < 0.01), respectively. Two of 31 patients with cervical stump failure were noted, one in the IMRT group and the other in the helical tomotherapy group. No acute or late grade 3 or 4 toxicities were noted, including proctitis, or genitourinary or gastrointestinal disturbances.

Conclusion

Helical tomotherapy is as effective as IMRT and has better uniformity and conformal indices, and critical organ-sparing properties. Prospective clinical trials are needed to evaluate the comparative efficacy of IMRT versus helical tomotherapy.

[Dosimetric comparison between the intensity modulated radiotherapy with fixed field and Rapid Arc of cervix cancer]

PURPOSE

Concurrent radiochemotherapy is the standard treatment for locally advanced cervical cancer. This treatment is responsible for bowel and hematologic toxicities. The use of intensity-modulated radiotherapy (IMRT), in static beams, allows a decrease of this toxicity. The technique of RapidArc(®) IMRT could lower the dose delivered to the organs at risk and improve the homogeneity of the planning target volume coverage, while decreasing the processing time.

PATIENTS AND MATERIALS

For 20 patients, treatment plans performed with IMRT and RapidArc(®) were compared. The target volumes were: the clinical target volume (gross tumour volume, uterus, upper third of the vagina, the hypogastric, iliac and presacral nodal regions), and the planning target volume (clinical target volume+1cm). The delineated organs at risk were: rectum, bladder, bowel and bone marrow. The dose was 45 Gy in 25 fractions. IMRT were delivered with five beams and RapidArc(®) with two arcs. The comparisons were made by the non-parametric test of Wilcoxon.

RESULTS

Medium coverage of the planning target volume was better with RapidArc(®) (P=0.01). It was also better regarding the sparing of bowel (P=0.01) and IMRT was better regarding the sparing of bladder (P=0.01) and rectum (P=0.05). The total volume receiving 20 Gy was less important with RapidArc(®) (P<0.001). RapidArc(®) allowed to decrease the treatment time (3 versus 12 minutes with IMRT) and the number of monitor units (MU) (376.5 versus 962.2, on average, P=0.0001).

CONCLUSION

The technique of RapidArc(®) seems to obtain better dosimetric results compared to RCMI, with fewer MU, and a significant decrease in treatment time.

[Normal tissue tolerance to external beam radiation therapy: small bowel]

The small bowel is a hollow organ involved in the transit and absorption of food. In relation to its anatomical location, a significant amount of this organ is exposed in whole or in part to ionizing radiation in external radiotherapy during abdominal or pelvic irradiation either for primary cancers or metastasis. The acute functional changes during external beam radiation are mainly leading to diarrhea, abdominal pain and bloating. The main late side effects of irradiation of the small intestine are chronic diarrhea, malabsorption with steatorrhea, abdominal spasms, intestinal obstruction, bleeding and fistulas. The architecture of the small intestine may be considered as parallel with a significant correlation between the irradiated volume of small bowel and the likelihood of acute toxicity, whatever the dose. The literature analysis recommends to consider the volume of small bowel receiving 15 Gy (threshold of 100 to 200 cm(3)) but also 30 and 50 Gy (thresholds of 35 to 300 cm(3), depending on the level of dose considered). Modern techniques of conformal radiotherapy with modulated intensity will probably have beneficial impact on small bowel toxicity.

Intensity-modulated radiotherapy in patients with cervical cancer. An intra-individual comparison of prone and supine positioning

Background

Chemoradiation for cervical cancer patients is associated with considerable gastrointestinal toxicity. Intensity-modulated radiotherapy (IMRT) has demonstrated superiority in terms of target coverage and normal tissue sparing in comparison to conventional 3D planning in gynaecological malignancies. Whether IMRT in prone (PP) or supine position (SP) might be beneficial for cervical cancer patients remains partially unanswered.

Methods

10 patients on FIGO stage IB-III cervical cancer, 6 patients for definitive and 4 patients for adjuvant external beam pelvic RT, were planned in PP and SP using a 7-field IMRT technique. IMRT plans for PP and SP (mean dose, D_mean 50.4 Gy) were optimized in terms of PTV coverage (1^st priority) and small bowel sparing (2^nd priority). A comparison of DVH parameters for PTV, small bowel, bladder, and rectum was performed.

Results

The comparison showed a similar PTV coverage of 95% of the prescribed dose and for target conformity in IMRT plans (PP, SP). PTV, rectum and bladder volumes were comparable for PP and SP. Significantly larger volumes of small bowel were found in PP (436 cc, + 35%, p = 0.01). PP decreased the volume of small bowel at 20-50.4 Gy (p < 0.05) and increased the rectum volumes covered by doses from 10-40 Gy (p < 0.01), the V50.4 was < 5% in both treatment positions. Bladder sparing was significant better at 50.4 Gy (p = 0.03) for PP.

Conclusion

In this dosimetric study, we demonstrated that pelvic IMRT in prone position for patients with cervical cancer seems to be beneficial in reducing small bowel volume at doses ≥20 Gy while providing similar target coverage and target conformity. The use of frequent image guidance with KV (kilovolt) or MV (megavolt) computertomography can reduce set-up deviations, and treatment in prone position can be done with a higher set-up accuracy. Clinical outcome studies are needed to affirm lower toxicity.

Optimization of photon beam energy in aperture-based inverse planning

Optimal choice of beam energy in radiation therapy is easy in many well‐documented cases, but less obvious in some others. Low‐energy beams may provide better conformity around the target than their high‐energy counterparts due to reduced lateral scatter, but they also contribute to overdosage of peripheral normal tissue. Beam energy was added as an optimization parameter in an automatic aperture‐based inverse planning system. We have investigated a total of six cases for two sites (prostate and lung), representative of deep‐seated and moderately deep‐seated tumors. For one case for each site, different numbers of beam incidences were considered. The other cases for each site were optimized using a fixed number of incidences. Four types of plans were optimized: 6 MV, 23 MV, and mixed energy plans with one or two energies per incidence. Each plan was scored with a dose‐volume cost function. Cost function values, number of segments, monitor units, dose‐volume parameters, and isodose distributions were compared. For the prostate and lung cases, energy mixing improved plans in terms of cost function values, with a more important reduction for a small number of beam incidences. Use of high energy allowed better peripheral tissue sparing, while keeping similar target coverage and sensitive structures avoidance. Low energy contribution to monitor units usually increased with the number of beam incidences. Thus, for deep‐seated and moderately deep‐seated tumors, energy optimization can produce interesting plans with less peripheral dose and monitor units than for low energy alone.

PACS numbers: 87.55.de, 87.55.dk, 87.56.N‐