Dose-volumetric parameters of acute esophageal toxicity in patients with lung cancer treated with three-dimensional conformal radiotherapy

Exposure to both radiation and chemotherapy increases the risk of Barrett's and multilayered epithelium

The relationship between radiation and/or chemotherapy and the development of Barrett's and/or multilayered epithelium has not been investigated before. We ascertained a group of patients exposed to radiation and/or chemotherapy and an unexposed group to compare the prevalence rates of Barrett's epithelium and multilayered epithelium at the time of endoscopy in these two groups. Barrett's epithelium was found in ten of the 19 (53%) exposed patients, compared to eight of 38 (21%) unexposed subjects (P = 0.02). Six of 19 (32%) exposed patients had multilayered epithelium, compared to four of 38 (11%) unexposed subjects (P = 0.06). Twelve of the 19 exposed patients (63%) had either Barrett's or multilayered epithelium, in contrast to ten of 38 (26%) unexposed subjects (P = 0.01). Those with exposure to both chemotherapy and radiation had a significant increase in the risk for Barrett's and/or multilayered epithelium (P = 0.003). This study suggests a relationship between exposure to a combination of radiation and chemotherapy and the development of Barrett's and/or multilayered epithelium.

Systematic review of dose-volume parameters in the prediction of esophagitis in thoracic radiotherapy

PURPOSE

With dose escalation and increasing use of concurrent chemoradiotherapy, radiation esophagitis (RE) remains a common treatment-limiting acute side effect in the treatment of thoracic malignancies. The advent of 3DCT planning has enabled investigators to study esophageal dose-volume histogram (DVH) parameters as predictors of RE. The purpose of this study was to assess published dosimetric parameters and toxicity data systematically in order to define reproducible predictors of RE, both for potential clinical use, and to provide recommendations for future research in the field.

MATERIALS AND METHODS

We performed a systematic literature review of published studies addressing RE in the treatment of lung cancer and thymoma. Our search strategy included a variety of electronic medical databases, textbooks and bibliographies. Both prospective and retrospective clinical studies were included. Information relating to the relationship among measured dosimetric parameters, patient demographics, tumor characteristics, chemotherapy and RE was extracted and analyzed.

RESULTS

Eighteen published studies were suitable for analysis. Eleven of these assessed acute RE, while the remainder assessed both acute and chronic RE together. Heterogeneity of esophageal contouring practices, individual differences in information reporting and variability of RE outcome definitions were assessed. Well-described clinical and logistic modeling directly related V(35Gy), V(60Gy) and SA(55Gy) to clinically significant RE.

CONCLUSIONS

Several reproducible dosimetric parameters exist in the literature, and these may be potentially relevant in the prediction of RE in the radiotherapy of thoracic malignancies. Further clarification of the predictive relationship between such standardized dosimetric parameters and observed RE outcomes is essential to develop efficient radiation treatment planning in locally advanced NSCLC in the modern concurrent chemotherapy and image-guided IMRT era.

Predictors of acute esophagitis in lung cancer patients treated with concurrent three-dimensional conformal radiotherapy and chemotherapy

PURPOSE

To evaluate the risk factors for acute esophagitis (AET) in lung cancer patients treated with concurrent 3D-CRT and chemotherapy.

METHODS AND MATERIALS

Data from 100 patients treated with concurrent chemoradiotherapy with a mean dose of 62.05 +/- 4.64 Gy were prospectively evaluated. Esophageal toxicity was graded according to criteria of the Radiation Therapy Oncology Group. The following dosimetric parameters were analyzed: length and volume of esophagus in treatment field, percentage of esophagus volume treated to >or=10, >or=20, >or=30, >or=35, >or=40, >or=45, >or=50, >or=55, and >or=60 Gy, and the maximum (D(max)) and mean doses (D(mean)) delivered to the esophagus. Also, we developed an esophagitis index (EI) to account the esophagitis grades over treatment time.

RESULTS

A total of 59 patients developed AET (Grade 1, 26 patients; Grade 2, 29 patients; and Grade 3, 4 patients). V50 was associated with AET duration (p = 0.017), AET Grade 1 duration (p = 0.016), maximum analgesia (p = 0.019), esophagitis index score (p = 0.024), and AET Grade >or=1 (p = 0.058). If V50 is <30% there is a 47.3% risk of AET Grade >or=1, which increases to 73.3% if V50 is >or=30% (p = 0.008). The predictive abilities of models (sensitivity and specificity) were calculated by receiver operating characeristic curves.

CONCLUSIONS

According to the receiver operating characeristic curve analysis, the 30% of esophageal volume receiving >or=50 Gy was the most statistically significant factor associated with AET Grade >or=1 and maximum analgesia (A(max)). There was an association with AET Grade >or=2 but it did not achieve statistical significance (p = 0.076).

Prevention of acute radiation-induced esophagitis with glutamine in non-small cell lung cancer patients treated with radiotherapy: evaluation of clinical and dosimetric parameters

BACKGROUND

The purpose of this study was to evaluate the efficacy of oral glutamine in the prevention of acute radiation-induced esophagitis (ARIE) and weight loss in lung carcinoma patients, and to determine the clinical/dosimetric predictors of ARIE.

PATIENTS AND METHODS

Data from 41 patients with stage III lung carcinoma treated with thoracic irradiation were retrospectively analyzed. Twenty-two patients (53.6%) received prophylactic powdered glutamine in doses of 10g/8h. Prescribed radiation dose to planning target volume was 60Gy, in 30 fractions, 5 days/week. The primary endpoint included the ARIE incidence and its correlation with clinical/dosimetric factors relative to treatment with glutamine.

RESULTS

Glutamine was well tolerated. Grade 2 or 3 ARIE occurred in 20 (48.8%) of 41 patients: seven in the glutamine-supplemented group, and 13 in the glutamine-free group (p=0.002). All seven patients with grade 3 esophagitis were in the glutamine-free group (36.8% vs. 0%). Glutamine supplementation appeared to significantly delay ARIE onset for six days (22 days vs. 16 days; p=0.002). Glutamine-supplemented patients demonstrated a lower incidence of grade 2 or 3 ARIE (27.2%), and gained weight during radiotherapy (p=0.04). V55 was the only dosimetric parameter that correlated with the severity of ARIE in glutamine-free patients: a V55 of <35% had a 31% risk of ARIE grade 2 or 3, and the risk increased to 76% with a V55 of >or=35% (p=0.01).

CONCLUSION

This schedule and dosage of glutamine may be beneficial in the prevention of ARIE and weight loss in lung cancer patients undergoing thoracic irradiation.

[Progress in radiation therapy and integration in Tenon hospital (AP-HP) of new advances in routine practices of radiotherapy for non-small-cell lung cancer]

Much progress has been made in recent years in administration modalities for external radiotherapy of non-small-cell lung carcinoma. Three-dimensional conformal radiotherapy with or without intensity modulation, with respiratory gated radio-therapy (4D radiotherapy), and image-guided radiotherapy (IGRT) can be considered as a third revolution in radiation therapy after total dose fractionation and the development of megavoltage radiation therapy equipment. We describe progress in the three-dimensional radiotherapy technique and the integration of this technique in the department of Radiation Oncology at Tenon hospital (AP-HP).

Prevention of radiochemotherapy-induced esophagitis with glutamine: results of a pilot study

PURPOSE

To assess the usefulness of oral glutamine to prevent radiochemotherapy-induced esophagitis in patients with lung cancer, and to determine the dosimetric parameter predictive of esophagitis.

METHODS AND MATERIALS

Seventy-five patients were enrolled; 34.7% received sequential radiochemotherapy, and 65.3% received concomitant radiochemotherapy. Every patient received prophylactic glutamine powder in doses of 10 g/8 h. Prescribed radiation doses were 45-50 Gy to planning target volume (PTV)1 (gross tumor volume plus wide margins) and 65-70 Gy to PTV2 (reduced margins). The primary endpoint was the incidence of Grade 2 or greater acute esophagitis.

RESULTS

No patient experienced glutamine intolerance or glutamine-related toxicity. Seventy-three percent of patients who received sequential chemotherapy and 49% of those who received concomitant chemotherapy did not present any form of esophagitis. V50 was the dosimetric parameter with better correlation between esophagitis and its duration. A V50 of <or=30% had a 22% risk of esophagitis Grade >or=2, which increased to 71% with a V50 of >30% (p = 0.0009).

CONCLUSIONS

The use of oral glutamine may have an important role in the prevention of esophageal complications of concomitant radiochemotherapy in lung cancer patients. However, randomized trials are needed to corroborate that effect. V50 is the dosimetric parameter with better correlation with esophagitis grade and duration.

Is there a selection bias in radiotherapy dose-escalation protocols?

BACKGROUND

To investigate the existence of a selection bias using a virtual radiotherapy dose-escalation trial. In dose-escalation trials, normal tissue constraints generally remain constant while the tumor dose is increased. Since tumor dose and normal tissue constraints are competing demands, a point will be reached at which the tumor dose cannot be increased without exceeding normal tissue constraints.

METHODS AND MATERIALS

In 9 patients with non-small-cell lung cancer, the tumor dose was escalated from 66 Gy to 78 Gy in 4-Gy dose levels using intensity-modulated radiotherapy planning, while the limiting normal tissue dose constraints remained constant. Dosimetric, radiobiologic, and other planning parameters were compared at the 66-Gy dose level for patients eligible for all dose levels and for those eligible only for lower dose levels.

RESULTS

Seven of 9 patients were eligible for all dose levels (Group E). Two of 9 patients ("ineligible" or Group I) qualified only for lower total doses (95% confidence interval, 0.075-0.6, significant). In Group E, mean planning target volumes were smaller (132 vs. 404 cm(3), nonsignificant), monitor units per fraction were significantly lower (448 vs. 802, p = 0.0008), and the average composite score for plan quality was better than in Group I (0.012 vs. 0.068, nonsignificant). Average tumor-control probabilities were higher (0.33 vs. 0.23, nonsignificant), and normal tissue-complication probabilities were lower for Group E than for Group I.

CONCLUSIONS

Patients eligible for higher dose levels had significantly superior estimated outcome parameters. A method to eliminate this source of error in the interpretation of dose-escalation trials is suggested.

Conformal therapy improves the therapeutic index of patients with anal canal cancer treated with combined chemotherapy and external beam radiotherapy

PURPOSE

To evaluate the clinical outcomes of three-dimensional conformal radiotherapy (3D-CRT) in patients with anal canal cancer, in terms of local control (LC), freedom from relapse (FFR), and overall survival (OS) rates, and to estimate long-term toxicity data.

METHODS AND MATERIALS

Sixty historical patients, treated with conventional radiation techniques (C-RT), were used as controls, and 62 consecutive patients were treated with 3D-CRT. Patients treated with 3D-CRT received 54 Gy in 30 fractions delivered continuously, compared with 45-58.9 Gy (median dose, 54 Gy) in a split course in patients treated with C-RT. Chemotherapy consisted of 5-fluorouracil with either mitomycin-C or cis-platinum given concurrently with radiation. Survival curves were performed using the Kaplan-Meier model, and the Cox proportional hazards model was used for multivariate analysis of risk factors.

RESULTS

No differences in stage and age distribution were observed between the two groups. Patients treated with 3D-CRT and C-RT had an actuarial 5-year LC rate of 85.1% and 61.1%, respectively (p = 0.0056); the FFR rate was 70.2% and 46.1% (p = 0.0166), and the OS rate was 80.7% and 53.9% (p = 0.0171). In multivariate analysis, factors of significance for LC were nodal (N) status (p < 0.001); for OS, 3D-CRT (p = 0.038), N status (p = 0.011), and T status (p = 0.012); and for FFR, 3D-CRT (p = 0.024) and N status (p < 0.001).

CONCLUSION

The use of 3D-CRT allows patients with anal canal cancer to complete radiation and chemotherapy without interruption for toxicity, with significant improvements in LC, FFR, and OS.

An analysis of 6-MV versus 18-MV photon energy plans for intensity-modulated radiation therapy (IMRT) of lung cancer

PURPOSE

To analyse the supposed benefits of low over high photon energies for the radiotherapy of lung cancer.

MATERIALS AND METHODS

For 13 patients, 6- and 18-MV IMRT planning was performed using identical planning objectives and dose constraints. Plans were compared according to dose-volume histogram (DVH) analysis including conformity and homogeneity indices (CI and HI) and overall plan quality (composite score CS), considering also magnitude and location of planning target volumes (PTVs).

RESULTS

With 6-MV plans, CSs were better in 11/13, HIs in 10/13 and CIs in 6/13 patients compared with 18-MV plans. Six-MV plans resulted in a better normal tissue sparing except for specified dose levels to the thorax and spinal cord. On average differences between 6 and 18 MV both for the PTV and normal tissues were not statistically significant (p>0.05). Considering size and location of the PTVs as well as their relative position to normal tissue, overall no significant differences between 6 and 18 MV were observed.

CONCLUSIONS

On average no clinically or statistically significant differences between 6- and 18-MV plans were observed. High photon energies should therefore not be excluded a priori when a dose-calculation algorithm is utilized that accurately accounts for heterogeneities.

Predictive factors for acute esophageal toxicity in thoracic radiotherapy

Acute esophageal toxicity (AET) is a common complication and dose-limiting toxicity in thoracic radiotherapy. Previous studies demonstrated several clinical and dosimetric parameters of AET in patients with lung cancer. However, there are few reports dealing with these variables in intra-thoracic malignancies, including lung cancer and other thoracic malignancy. The purpose of this study was to evaluate the clinical and dosimetric factors associated with AET in patients with intra-thoracic malignancies. We examined 61 patients with intra-thoracic malignancies treated with radiotherapy: 34 patients with non-small-cell lung cancer (55%), 9 cases with small-cell lung cancer (15%), 7 cases with thymic cancer (11%), 4 thymomas (7%), 2 malignant lymphomas (3%), one seminoma (2%), one liposarcoma (2%), and 3 cases of other malignancies (5%). Radiotherapy was performed with a median dose of 60 Gray (Gy) (range 40-67 Gy). AET was graded according to the Radiation Therapy Oncology Group (RTOG) criteria. The following parameters were analyzed with respect to associations with AET by univariate and multivariate analyses: age, gender, thoracic surgery before radiotherapy, concurrent chemotherapy, duration of radiotherapy, maximum esophageal dose, mean esophageal dose, and percentage of esophageal volume receiving from 10 Gy (V10) to 65 Gy (V65), in 5-Gy increments. 43 patients (70%) developed AET: 36 patients (59%) with AET of RTOG Grade 1, 7 patients (11%) with Grade 2, and no patients (0%) with Grade 3 or worse. On multivariate analysis, V35 > 30% was the most statistically significant factor associated with mild AET (p = 0.013). Our findings provide a better understanding of the factors related to AET, and might be useful in designing a treatment plan to prevent severe esophageal toxicity.