Predictors of toxicity after curative reirradiation with intensity modulated radiotherapy or proton therapy for recurrent head and neck carcinoma: new dose constraints for pharyngeal constrictors muscles and oral cavity

BACKGROUND

Our study aims to identify predictive factors of moderate to severe (grade ≥ 2) late toxicity after reirradiation (reRT) of recurrent head and neck carcinoma (HNC) and explore the correlations between dose organs at risk (OAR) and grade ≥ 2 toxicity.

MATERIAL AND METHODS

Between 09/2007 and 09/2019, 55 patients were re-irradiated with IMRT or proton therapy with curative intent for advanced HNC. Our study included all patients for whom data from the first and second irradiations were available. Co-variables, including interval to reRT, size of re-irradiated PTV, and dose to OAR, were analyzed as potential predictors for developing moderate to severe long-term toxicity with death as a competing risk. Receiver-operator characteristics (ROC) analysis assessed the association between dose/volume parameters and the risk of toxicity.

RESULTS

Twenty-three patients participated in our study. After a median follow-up of 41 months, 65% of the patients experienced grade ≥ 2 late toxicity. The average dose to pharyngeal constrictor muscles (PCM) at the time of reRT showed an association with the risk of grade ≥ 2 dysphagia: AUC = 0.78 (95% CI: 0.53-1), optimal cut-off value = 36.7 Gy (sensitivity 62%/specificity 100%). The average dose to the oral cavity at the time of reRT showed an association with the risk of grade ≥ 2 dysgeusia: AUC = 0.96 (0.89-1), optimal cut-off value = 20.5 Gy (sensitivity 100%/specificity 88%).

CONCLUSION

Our analysis depicted an association between the dose to OAR and the risk of developing moderate to severe dysphagia and dysgeusia and proposed new dose constraints for PCM (36.7 Gy) and oral cavity (20.5 Gy).

Long-term efficacy and tolerance of a technique for postmastectomy electron beam radiation therapy of the unreconstructed chest wall and lymph node areas for non-metastatic breast cancers

PURPOSE

To evaluate the long-term tolerance and outcome of patients irradiated with an electron beam technique used since 2007 on the chest wall and lymph node areas after mastectomy for non-metastatic locally advanced breast carcinoma.

PATIENTS AND METHODS

All patients irradiated with an improved electron beam technique after mastectomy for non-metastatic breast carcinoma between 2007 and 2011 at Institut Curie (France) were included in this descriptive study. The technique has already been described in other studies, as has its 5-year tolerance and non-inferiority compared to photon irradiation. Acute and chronic toxicity were collected using CTCAE v 3.0. A clinical examination was carried out each week during the radiotherapy and at each 6 months consultation with one mammogram per year at the Institut Curie for at least 5 years. The patients then continued to be followed either at the Institut Curie or in private practice with a good transmission of outpatient consultations, thanks to a system of forms to be completed and integrated into the electronic files. Quantitative and qualitative data are defined by mean and proportion. Statistical comparisons were made by computer using the Chi2 test and Fisher's exact test for categorical variables. Recurrence-free survival was defined as the time between the end of treatment and the date of recurrence or death. Overall survival was defined in the same way without taking into account recurrences. Patients who did not report any events were censored at the date of last news.

RESULTS

Of the 796 patients included, 51.3% had multifocal lesions, 10.1% had triple negative status, and 18.8% displayed overexpression of the Her2 receptor, 196 (24.6%) patients received neoadjuvant chemotherapy and 208 (26.1%) systemic treatment during radiotherapy (chemotherapy or targeted therapy); 514 (64.6%) had at least one positive lymph node. The internal mammary chain (IMC) was irradiated in 85.6% of cases, the supraclavicular areas in 88.3% of cases, the infraclavicular in 77.9% of cases and the axillary area in 14.9% of cases. With a median follow-up of 113 months (range: 2-164 months), locoregional recurrence-free survival and overall 10-year survival was respectively 94.02%, (95% CI: 92.13-98.94) and 79.84% (95% CI: 76.83-82.97). Median survival was not reached. In the long term, 29.6% of patients had telangiectasias (grade 1: 23.3%, grade 2: 5.2%, grade 3: 1.1%). There were 279 patients (35.1%) with secondary breast reconstruction on average 21 months after all treatments. IMC irradiation was not associated with a majority of pulmonary toxicity. Thirty-five patients developed chronic heart disease after radiotherapy, 30 of whom had received anthracyclines and 9 had received traztuzumab. Three of these reported a coronary ischaemic event, including 2 irradiated on the left and 1 on the right, the 4 were irradiated in the vicinity of the IMC and the other lymph node areas, but presented many other cardiovascular risk factors (between 2 and 4). During follow-up, 4.9% of patients had a contralateral recurrence (n=39) and 5.5% had a second non-breast cancer (n=44), of the 6 bronchopulmonary cancers diagnosed, none appeared to be related to chest wall radiotherapy.

CONCLUSION

This study confirms that the improved postmastectomy electron beam radiation therapy technique is well-tolerated after nearly 10 years of follow-up.

Radiation dose to the low axilla in patients treated for early-stage breast cancer by locoregional intensity-modulated radiotherapy (IMRT)

PURPOSE

To determine the dose received by the low axilla during locoregional radiotherapy (RT) for early-stage breast cancer and to assess the impact of the treatment technique (three-dimensional conformal radiotherapy (3D-CRT) or rotational IMRT (VMAT) or helical tomotherapy (HT).

MATERIALS AND METHODS

The dosimetric study was performed on patients receiving normofractionated (NFRT - 50Gy in 25 fractions) or hypofractionated (HFRT - 40Gy in 15 fractions) locoregional radiotherapy (breast or chest wall and internal mammary, supraclavicular and infraclavicular nodes±axillary nodes) by 3D-CRT or VMAT or HT at the Institut Curie Paris. Patients treated by breast-conserving surgery received a boost dose of 16Gy and 10Gy to the tumour bed, respectively.

RESULTS

Sixty-eight patients treated by RT from February 2017 to January 2019 were studied. The mean dose received by the low axilla when it was not part of the target volume was 30.8Gy, 41.0Gy and 44.4Gy by 3D-CRT, VMAT and HT, respectively for NFRT and 24.2Gy, 33.0Gy and 34.9Gy, respectively, for HFRT. With NFRT, 4.1% of the axilla received 95% (V95) of the prescribed dose by 3D-CRT compared to 24.5% and 33.6% by VMAT and HT, respectively; with HFRT, V95 was 3.9%, 19.5% and 24.1%, respectively.

CONCLUSION

The axilla receives a non-negligible dose during locoregional radiotherapy; this dose is greater when VMAT or HT are used. Prospective studies must be conducted to assess the impact of this axillary dose in terms of morbidity, which currently remains unknown.

High-dose proton therapy and tomotherapy for the treatment of sacral chordoma: a retrospective monocentric study

OBJECTIVE

Radiation therapy (RT) is used for the treatment of sacral chordoma, in combination with surgery or alone for unresected tumours, to improve local control (LC) and potentially overall survival (OS). The purpose of the present study was to evaluate efficacy and toxicity of proton therapy (PT), and/or intensity modulated radiation therapy (IMRT), particularly Tomotherapy, for sacral chordoma treatment. Material: Between November 2005 and June 2018, 41 consecutive patients who were not included in clinical trials, received sacral chordoma radiation treatment in Institut Curie with Tomotherapy alone in 13 patients, and combined PT and Tomotherapy boost (Proton - Tomo) in 28 patients. RT was delivered as the exclusive local treatment in 11 patients, and as a post-operative complementary treatment in 30 patients.

RESULTS

After a median follow-up of 46 months (range, 0-125 months), eight local relapses were observed, and seven patients developed distant metastasis (particularly bone and lung). The 2- and 5- year local relapse rates were 11.4% CI (0.65-22.2%) and 29% (10.5-47.4%), respectively. Over the follow-up period, ten patients died (24.4%). The estimated 2- and 5-year OS rates were 91.4% CI (82.5-100%) and 74.5% (59.4-93.5%), respectively. Fibrosis, cauda equina syndrome, and pain were the most common late toxicities. The comparison between Tomotherapy alone and Proton - Tomo revealed that acute and late cystitis were significantly more frequent in the Tomotherapy group: SHR = 0.12 IC95% (0.01-0.90 [p = .04]), as well as late proctitis. A dosimetric comparison confirmed the interest of PT to spare rectum and bladder in this context.

CONCLUSION

RT remains essential to improve local control in sacral chordoma. The combination of proton and photon seems to improve organ at risk sparing, resulting in a decreased rate of reported late toxicities.

Dosimetric comparison of four high performance techniques for irradiation of breast cancer patients

PURPOSE

The use of IMRT for the treatment of breast cancer has been growing considerably in our institution since 2009. Alternatively, helical tomotherapy (HT) using a field width of 2.5 and 5cm (HT_FW_5), volumetric-modulated arc therapy (VMAT), or proton therapy with pencil-beam scanning (PT-PBS) have also been used to reduce treatment duration or optimize organ-at-risk (OAR) sparing. The purpose of this study was to compare the 4 treatment modalities available at our site.

PATIENTS AND METHODS

We studied 10 patients treated for breast cancer with lymph node involvement. The prescribed dose was 51.8Gy to the breast with a simultaneous integrated boost up to 63Gy, and 50.4Gy to lymph nodes in 28 fractions. The CTV was delineated according to ESTRO Guidelines. Dosimetric planning in routine clinical practice was performed using HT_FW_2.5. The approved clinical plan was compared to the 3 other plans. Dosimetric goals for PTV coverage were D95%≥95% and D2%≤107% of the prescribed dose. Mean and maximum doses to OAR were recorded.

RESULTS

HT_FW_5 and VMAT plans ensure equivalent or even better PTV coverage compared to the initial clinically approved plan but at the cost of poorer OAR sparing. PT_PBS plans showed that an excellent PTV coverage can be maintained with significantly lower doses to OAR.

CONCLUSION

HT_FW_5 and VMAT plans allow a significant reduction of treatment duration and can be a good alternative to HT_FW_2.5 for specific populations. HT_FW_2.5 could be chosen for patients at higher risk of side effects. In addition, PT_PBS should be considered in the near future as it has been shown to have a major potential benefit to lower the risk of side effects with the same level of PTV coverage.

Abstract P3-12-20: The use of new delineation tool “MIRADA”, step-by-step development and first results of its use in early and locally advanced breast cancer patients

Objectives: To describe the practical procedure of implementation and optimization of delineation using “Mirada” software, as well as evaluation of the automatic segmentation for the daily practice of lymph nodes (LN) and OARs (organs at risk) in early as well as locally advanced stage breast cancer patients.

Methods: Forty patients' CT scans in treatment position were selected and re-contoured according to the ESTRO guidelines. The atlas of dataset was then created for automatic delineation. Thirty patients with breast/chest wall and lymph nodes regions irradiated were recruited for evaluation. With the same treatment position, the CT scan images were acquired and then contoured by the MIRADA system automatically as well as by the radiation oncologist manually (as the reference). The Conformity Index (CI) was used to evaluate the concordance between both of them.

Results: The mean time for manual contour was 24.1±5.1 mins and 26.4±2.8 mins for the LN and the OARs resp. All the volumes of interest were contoured using the software (including corrections) in 30 minutes, which reduced the time of delineation of target volumes and OAR by about 40%. Of the 30 cases evaluated, the mean CI of 5 principal OARs showed ≥ 0.8. While the automatic contour of LN was less satisfactory with mean CI of 0.43±0.1 (0.23-0.52).

Conclusions: For the breast cancer patients, the studied software permitted to save time for delineation with acceptable OAR contours. The improvement of LN regions contour is needed. More cases and further evaluation are needed for the system to realize its routine use.

Citation Format: Xu H, Arsene Henry A, Robillard M, Amessis M, Kirova YM. The use of new delineation tool “MIRADA”, step-by-step development and first results of its use in early and locally advanced breast cancer patients [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-12-20.

The use of new delineation tool "MIRADA" at the level of regional lymph nodes, step-by-step development and first results for early-stage breast cancer patients

OBJECTIVE:

To describe the practical procedure of implementation and optimization of delineation using "Mirada" software, as well as evaluation of the automatic segmentation for the daily practice of lymph nodes (LN) and organs at risk (OARs) in early stage breast cancer patients.

METHODS:

40 patients' CT scans in treatment position were selected and recontoured according to the European Society of Therapeutic Radiation Oncology guidelines. The atlas of data set was then created for automatic delineation. 30 patients with breast/chest wall and lymph nodes regions irradiated were recruited for evaluation. With the same treatment position, the CT scan images were acquired and then contoured by the MIRADA system automatically as well as by the radiation oncologist manually (as the reference). The conformity index (CI) was used to evaluate the concordance between both of them.

RESULTS:

The mean time for manual contour was 24.1 ± 5.1 and 26.4 ± 2.8 min for the LN and the OARs respectively. All the volumes of interest were contoured using the software (including corrections) in 30 min, which reduced the time of delineation of target volumes and OAR by about 40%. Of the 30 cases evaluated, the mean CI of 5 principal OARs showed ≥0.8. While the automatic contour of LN was less satisfactory with mean CI of 0.43 ± 0.1 (0.23-0.52).

CONCLUSION:

For the breast cancer patients, the studied software permitted to save time for delineation with acceptable OAR contours. The improvement of LN regions contour is needed. More cases and further evaluation are needed for the system to realize its routine use.

ADVANCES IN KNOWLEDGE:

It's the first description and evaluation of the automatic delineation and segmentation system for the breast cancer.

Pelvic insufficiency fracture (PIF) incidence in patients treated with intensity-modulated radiation therapy (IMRT) for gynaecological or anal cancer: single-institution experience and review of the literature

OBJECTIVE

To summarize the results of pelvic insufficiency fracture (PIF) incidence in patients with anal or gynaecological cancer treated by pelvic intensity-modulated radiation therapy (IMRT).

METHODS

The clinical and morphological (CT and/or pelvic MRI) characteristics of patients treated by IMRT at our institution between 2007 and 2014 were analyzed. The global incidence of PIF after external beam radiotherapy and the impact of tumour site (gynaecological or anal cancer) were determined. A dosimetric study was then performed to compare patients with and without pelvic fracture.

RESULTS

341 patients were treated by IMRT for gynaecological or anal cancer between 2007 and 2014. 15 patients experienced at least 1 pelvic fracture after external beam radiotherapy, corresponding to an overall incidence of 4.4%. Age and menopausal status were correlated with an increased fracture risk (p = 0.0274 and p < 0.0001, respectively). The site of the primary tumour (gynaecological or anal canal) was not associated with an excess fracture risk. The median maximum dose received at the fracture site was 50.3 Gy (range: 40.8-68.4 Gy).

CONCLUSION

The incidence of pelvic fracture after IMRT is low, but is higher after the age of 50 and in patients who are postmenopausal. Pre-treatment evaluation of bone density by bone densitometry and phosphorus-calcium assessment could be useful prior to the management of these patients. Advances in knowledge: Pelvic fractures are a frequent complication after radiotherapy. The influence of IMRT and clinical characteristics were evaluated in this study.

[Helical tomotherapy in the treatment of malignant pleural mesothelioma: The impact of low doses on pulmonary and oesophageal toxicity]

PURPOSE

To evaluate the adjuvant treatment of malignant pleural mesothelioma by helical tomotherapy and the impact of low doses on esophageal and pulmonary toxicity.

PATIENTS AND METHODS

Between June 2007 and May 2011, 29 patients diagnosed with malignant pleural mesothelioma received adjuvant radiotherapy by helical tomotherapy. The median age was 63 years (34-72). Histologically, 83 % of patients had epithelioid malignant pleural mesothelioma. Clinically, 45 % of patients were T3 and 55 % N0. Eighty six percent of the patients were treated by extrapleural pneumonectomy and 35 % received neoadjuvant chemotherapy with platinum and pemetrexed. The median dose in the pneumonectomy cavity was 50Gy at 2Gy/fraction.

RESULTS

The mean follow-up was 2.3 years after diagnosis. Overall survival at 1 and 2 years was 65 and 36 % respectively. The median survival from diagnosis was 18 months. Median lung volumes receiving 2, 5, 10, 13, 15 and 20Gy (V2, V5, V10, V13, V15 and V20) were 100, 98, 52, 36, 19 and 5 %. The median of the mean remaining lung dose was 11Gy. Two patients died of pulmonary complications, three patients had grade 3 lung toxicity, while esophageal grade 3-4 toxicity was observed in three other patients. No significant impact of clinical characteristics and dosimetric parameters were found on pulmonary toxicity, however a V10≥50 %, a V15≥15 % and mean lung dose of 10Gy or more had a tendency to be predictive of pulmonary toxicity (P<0.1). Moreover, in our analysis, the mean lung dose seems to have a significant impact on esophageal toxicity (P=0.03) as well as low doses to the controlateral lung: V5, V10 and V13 (P<0.05).

CONCLUSION

Helical tomotherapy is a promising technique in the multimodality treatment of malignant pleural mesothelioma. Low doses received by the contralateral lung appear to be the limiting factor. A dosimetric comparison with volumetric modulated arctherapy techniques would be interesting in this setting.

Further developments for improving response and tolerance to irradiation for advanced renal cancer: concurrent (mTOR) inhibitor RAD001 and helical tomotherapy

PURPOSE

Radiotherapy remains marginal in the treatment of renal cell carcinoma (RCC), due to radioresistance and risks of acute toxicity. However, recent data have shown that the m-TOR inhibitors could decrease the tumor resistance to ionizing radiation. At the same time, new highly conformal irradiation modalities may significantly improve the tolerance to radiation.

METHODS

Here, we report the first case of concurrent use of mTOR antagonist, rapamycin and Helical Tomotherapy and its potential in critical organs sparing in a patient with retroperitoneal relapse from a RCC. He was treated with Everolimus, 10 mg/d and concurrent Helical Tomotherapy to the region of the recurrence (45 Gy, 1.8 Gy per fraction).

RESULTS

Helical Tomotherapy allowed very sharp dose distributions around the target volumes, while sparing critical organs from useless radiation. No radiotherapy related acute toxicity was observed. At last follow-up (6 months later), the patient remains in partial remission at the irradiated region.

CONCLUSIONS

While targeted agents might find applications for radiosensitizing purposes, this report highlights the potential of Helical Tomotherapy for reducing the doses delivered to the critical organs, thus improving tolerance to irradiation.

Solitary plasmocytoma: improvement in critical organs sparing by means of helical tomotherapy

PURPOSE

Helical tomotherapy (HT) was assessed in two patients with paramedullar solitary bone plasmocytoma. We compared doses delivered to critical organs, according HT plan or tridimensional conformal plan.

METHODS AND MATERIALS

One male (patient no. 1), 67 yr-old and one female (patient no. 2), 37-yr-old, with histologically, biologically and radiological confirmed paramedullar solitary plasmocytoma have been treated in our department between November 2007 and February 2008 using HT. The prescription dose was 40 Gy in 20 fractions. This HT treatment planning was compared with a routine dosimetric work that was executed for a standard conformal radiotherapy treatment planning.

RESULTS

Treatment tolerance was excellent, without any side effects. Both patients achieved 9-month complete remission. HT resulted in substantial critical organs sparing. For patient no. 1, dose delivered to 20% of the total intestine volume was reduced from 28 Gy for conformal radiotherapy to 13 Gy for HT. Radiation dose delivered to 20% of the left kidney was reduced from 25 Gy to 7 Gy. For patient no. 2, volume of left lung that received at least 20 Gy was 12% for conformal radiotherapy vs. 6% for HT.

CONCLUSIONS

For paramedullar solitary plasmocytoma, HT has the potential to significantly improve the quality of the dose distribution both in terms of better dose homogeneity within the planning target volume and more efficient sparing of critical organs.