Target splitting in radiation therapy for lung cancer: further developments and exemplary treatment plans

Locally advanced NSCLC: a plea for sparing the ipsilateral normal lung-prospective, clinical trial with DART-bid (dose-differentiated accelerated radiation therapy, 1.8 Gy twice daily) by VMAT

Background

In radiation treatment of locally advanced non-small cell lung cancer (LA-NSCLC), ‘margins’ from internal target volumes to planning target volumes in the range of 12 to 23 mm are reported, and avoiding exposure of the contralateral lung is common practice. We investigated prospectively an approach with tight margins (7 mm) and maximal sparing of the ipsilateral normal lung. Mature results for the first endpoint (pneumonitis) and further toxicities are reported.

Methods

Primary tumors were treated by VMAT with 73.8–90.0 Gy in positive correlation to tumor volumes, nodes with 61.2 Gy, a restricted volume of nodes electively with 45 Gy. Fractional doses of 1.8 Gy bid, interval 8 h. Before radiotherapy, two cycles platin-based chemotherapy were given. 12 patients finished maintenance therapy with Durvalumab. Median follow up time for all patients is 19.4 months, for patients alive 27.0 months (3.4–66.5 months).

Results

100 consecutive, unselected patients with LA-NSCLC in stages II through IVA were enrolled (UICC/AJCC, 8th edition). No acute grade 4/5 toxicity occurred. Pneumonitis grade 2 and 3 was observed in 12% and 2% of patients, respectively; lowering the risk of pneumonitis grade ≥ 2 in comparison to the largest study in the literature investigating pneumonitis in LA-NSCLC, is significant (p < 0.0006). Acute esophageal toxicity grade 1, 2 and 3 occurred in 12%, 57% and 3% of patients, respectively. Two patients showed late bronchial stricture/atelectasis grade 2. In two patients with lethal pulmonary haemorrhages a treatment correlation cannot be excluded. Median overall survival for all stage III patients, and for those with ‘RTOG 0617 inclusion criteria’ is 46.6 and 50.0 months, respectively.

Conclusions

Overall toxicity is low. In comparison to results in the literature, maximal sparing the ipsilateral normal lung lowers the risk for pneumonitis significantly.

Trial registration

Ethics committee of Vorarlberg, Austria; EK-0.04-105, Registered 04/09/2017—Retrospectively registered. http://www.ethikkommission-vorarlberg.at

DART-bid for loco-regionally advanced NSCLC : Summary of acute and late toxicity with long-term follow-up; experiences with pulmonary dose constraints

Background

To report acute and late toxicity with long-term follow-up, and to describe our experiences with pulmonary dose constraints.

Methods

Between 2002 and 2009, 150 patients with 155 histologically/cytologically proven non-small cell lung cancer (NSCLC; tumor stages II, IIIA, IIIB in 6, 55 and 39%, respectively) received the following median doses: primary tumors 79.2 Gy (range 72.0–90.0 Gy), lymph node metastases 59.4 Gy (54.0–73.8 Gy), nodes electively 45 Gy; with fractional doses of 1.8 Gy twice daily (bid). In all, 86% of patients received 2 cycles of chemotherapy previously.

Results

Five treatment-related deaths occurred: pneumonitis, n = 1; progressive pulmonary fibrosis in patients with pre-existing pulmonary fibrosis, n = 2; haemorrhage, n = 2. In all, 8% of patients experienced grade 3 and 1.3% grade 4 pneumonitis; 11% showed late fibrotic alterations grade 2 in lung parenchyma. Clinically relevant acute esophagitis (grade 2 and 3) was seen in 33.3% of patients, 2 patients developed late esophageal stenosis (G3). Patients with upper lobe, middle lobe and central lower lobe tumours (n = 130) were treated with V20 (total lung) up to 50% and patients with peripheral lower lobe tumours (n = 14, basal lateral tumours excluded) up to 42%, without observing acute or late pulmonary toxicity >grade 3. Only patients with basal lateral lower lobe tumours (n = 5) experienced grade 4/5 pulmonary toxicity; V20 for this latter group ranged between 30 and 53%. The mean lung dose was below the QUANTEC recommendation of 20–23 Gy in all patients. The median follow-up time of all patients is 26.3 months (range 2.9–149.4) and of patients alive 80.2 months (range 63.9–149.4.). The median overall survival time of all patients is 26.3 months; the 2-, 5- and 8‑year survival rates of 54, 21 and 15%, respectively. The local tumour control rate at 2 and 5 years is 70 and 64%, the regional control rate 90 and 88%, respectively.

Discussion and conclusion

Grade 4 or 5 toxicity occurred in 7/150 patients (4.7%), which can be partially avoided in the future (e.g. by excluding patients with pre-existing pulmonary fibrosis). Tolerance and oncologic outcome compare favourably to concomitant chemoradiation also in long-term follow-up.

Normal tissue complication models for clinically relevant acute esophagitis (≥ grade 2) in patients treated with dose differentiated accelerated radiotherapy (DART-bid)

Background

One of the primary dose-limiting toxicities during thoracic irradiation is acute esophagitis (AE). The aim of this study is to investigate dosimetric and clinical predictors for AE grade ≥ 2 in patients treated with accelerated radiotherapy for locally advanced non-small cell lung cancer (NSCLC).

Patients and methods

66 NSCLC patients were included in the present analysis: 4 stage II, 44 stage IIIA and 18 stage IIIB. All patients received induction chemotherapy followed by dose differentiated accelerated radiotherapy (DART-bid). Depending on size (mean of three perpendicular diameters) tumors were binned in four dose groups: <2.5 cm 73.8 Gy, 2.5–4.5 cm 79.2 Gy, 4.5–6 cm 84.6 Gy, >6 cm 90 Gy. Patients were treated in 3D target splitting technique. In order to estimate the normal tissue complication probability (NTCP), two Lyman models and the cutoff-logistic regression model were fitted to the data with AE ≥ grade 2 as statistical endpoint. Inter-model comparison was performed with the corrected Akaike information criterion (AIC_c), which calculates the model’s quality of fit (likelihood value) in relation to its complexity (i.e. number of variables in the model) corrected by the number of patients in the dataset. Toxicity was documented prospectively according to RTOG.

Results

The median follow up was 686 days (range 84–2921 days), 23/66 patients (35 %) experienced AE ≥ grade 2. The actuarial local control rates were 72.6 % and 59.4 % at 2 and 3 years, regional control was 91 % at both time points. The Lyman-MED model (D50 = 32.8 Gy, m = 0.48) and the cutoff dose model (D_c = 38 Gy) provide the most efficient fit to the current dataset. On multivariate analysis V38 (volume of the esophagus that receives 38 Gy or above, 95 %-CI 28.2–57.3) was the most significant predictor of AE ≥ grade 2 (HR = 1.05, CI 1.01–1.09, p = 0.007).

Conclusion

Following high-dose accelerated radiotherapy the rate of AE ≥ grade 2 is slightly lower than reported for concomitant radio-chemotherapy with the additional benefit of markedly increased loco-regional tumor control. In the current patient cohort the most significant predictor of AE was found to be V38. A second clinically useful parameter in treatment planning may be MED (mean esophageal dose).

Electronic supplementary material

The online version of this article (doi:10.1186/s13014-015-0429-1) contains supplementary material, which is available to authorized users.

Target splitting non-coplanar RapidArc radiation therapy for a diffuse sebaceous carcinoma of the scalp: a novel delivery technique

Background and purpose

To compare conventional lateral photon-electron, fixed-beam intensity modulated radiation therapy (IMRT), coplanar and non-coplanar RapidArc for the treatment of a diffuse sebaceous gland carcinoma of the scalp.

Methods

Comprehensive dosimetry comparisons were performed among 3D-CRT, IMRT and various RapidArc plans. Target coverage, conformity index (CI), homogeneity index (HI) and doses to organs at risk (OAR) were calculated. Monitor unites (MUs) and delivery time of each treatment were also recorded to evaluate the execution efficiency. The influence of target splitting technique and non-coplanar planning on plan quality was discussed.

Results

IMRT was superior to 3D-CRT concerning targets’ coverage at the sacrifice of larger irradiated brain volumes to low doses. CIs and HIs were better in coplanar RapidArc and non-coplanar RapidArc plans than 3D-CRT and IMRT. Best dose coverage and sparing of OARs were achieved in non-coplanar plans using target splitting technique. Treatment delivery time was longest in the IMRT plan and shortest in the coplanar RapidArc plan without target splitting. The 3%/3 mm gamma test pass rates were above 95% for all the plans.

Conclusions

Target splitting technique and non-coplanar arcs are recommended for total scalp irradiation.

DART-bid (Dose-differentiated accelerated radiation therapy, 1.8 Gy twice daily)--a novel approach for non-resected NSCLC: final results of a prospective study, correlating radiation dose to tumor volume

Background

Sequential chemo-radiotherapies with intensive radiation components deliver promising results in non-resected non-small cell lung cancer (NSCLC). In general, radiation doses are determined by dose constraints for normal tissues, not by features relevant for tumor control. DART-bid targets directly the doses required for tumor control, correlating doses to tumor volume in a differentiated mode.

Materials/Methods

Radiation doses to primary tumors were aligned along increasing tumor size within 4 groups (<2.5 cm/2.5–4.5 cm/4.5–6.0 cm/>6.0 cm; mean number of three perpendicular diameters). ICRU-doses of 73.8 Gy/79.2 Gy/84.6 Gy/90.0 Gy, respectively, were applied. Macroscopically involved nodes were treated with a median dose of 59.4 Gy, nodal sites about 6 cm cranial to involved nodes electively with 45 Gy. Fractional doses were 1.8 Gy twice daily (bid).

2 cycles chemotherapy were given before radiotherapy.

Between 2004 and 2009, 160 not selected patients with 164 histologically/cytologically proven NSCLC were enrolled; Stage I: 38 patients; II: 6 pts.; IIIA: 69 pts.; IIIB: 47 pts. Weight loss >5%/3 months: 38 patients (24%).

Primary endpoints are local and regional tumor control rates at 2 years (as >90% of locoregional failures occur within 2 years). Secondary endpoints are survival and toxicity. With a minimum follow-up time of 2 years for patients alive, the final results are presented.

Results

32 local and 10 regional recurrences occurred. The local and regional tumor control rates at 2 years are 77% and 93%, respectively.

The median overall survival (OS) time is 28.0 months, the 2- and 5-year OS rates are 57% and 19%, respectively. For stage III patients, median OS amounts to 24.3 months, 2- /5-year OS rates to 51% and 18%, respectively.

2 treatment-related deaths (progressive pulmonary fibrosis) occurred in patients with pre-existing pulmonary fibrosis. Further acute and late toxicity was mild.

Conclusions

This novel approach yields a high level of locoregional tumor control and survival times. In general it is well tolerated. In all outcome parameters it seems to compare favourably with simultaneous chemo-radiotherapies, at present considered ‘state of the art’; and is additionally amenable for an unselected patient population.

Non-small cell lung cancer in stages I-IIIB: Long-term results of definitive radiotherapy with doses ≥ 80 Gy in standard fractionation

PURPOSE

To investigate therapeutic outcome of dose escalation ≥ 80 Gy in nonresected non-small cell lung cancer (NSCLC).

PATIENTS AND METHODS

124 consecutive patients with histologically/cytologically proven NSCLC were enrolled. Tumor stage I, II, IIIA, and IIIB was diagnosed in 30, eight, 39, and 47 patients, respectively. 38 patients (31%) had weight loss > 5% during the 3 months before diagnosis. A median dose of 88.2 Gy (range 80.0-96.0 Gy), 69.3 Gy (63.0-88.0 Gy) and 56.7 Gy was applied to primary lesions, involved lymph nodes, and elective nodes (within a region of about 6 cm cranial to macroscopically involved nodes), respectively. Daily fractional ICRU doses of 2.0-2.2 Gy were delivered by the conformal target-splitting technique. 58 patients (47%) received induction chemotherapy, in median two cycles prior to radiotherapy.

RESULTS

Median follow-up time of all patients was 19 months, of patients alive 72.4 months (69-121 months). The cumulative actual overall survival rate at 2 and 5 years amounts to 39% and 11.3%, respectively, resulting in a median overall survival time of 19.6 months. According to stages I, II, IIIA, and IIIB, the median overall survival times are 31.8, 31.4, 19.0, and 14.5 months, respectively. The locoregional tumor control rate at 2 years is 49%. Apart from one treatment-related death (pneumonitis), acute toxicity according to EORTC/RTOG scores was moderate: lung grade 2 (n = 7), grade 3 (n = 3); esophagus grade 1 (n = 11); heart grade 3 (n = 1, pericarditis). No late toxicity grade > 1 has been observed.

CONCLUSION

Sequential, conventionally fractionated high-dose radiotherapy by conformal target splitting is well tolerated. The results for survival and locoregional tumor control seem to at least equalize the outcome of simultaneous chemoradiation approaches, which, at present, are considered "state of the art" for patients with nonresected NSCLC. A higher potential of radiation therapy might be reached by accelerated fractionation regimens.

Nonresected non-small-cell lung cancer in Stages I through IIIB: accelerated, twice-daily, high-dose radiotherapy--a prospective Phase I/II trial with long-term follow-up

PURPOSE

Our purpose was to investigate the tolerability of accelerated, twice-daily, high-dose radiotherapy. The secondary endpoints were survival and locoregional tumor control.

METHODS AND MATERIALS

Thirty consecutive patients with histologically/cytologically proven non-small-cell lung cancer were enrolled. Tumor Stage I, II, IIIA, and IIIB was found in 7, 3, 12, and 8 patients, respectively. We applied a median of 84.6 Gy (range, 75.6-90.0 Gy) to the primary tumors, 63.0 Gy (range, 59.4-72.0 Gy) to lymph nodes, and 45 Gy to nodes electively (within a region of about 6 cm cranial to macroscopically involved sites). Fractional doses of 1.8 Gy twice daily, with an interval of 11 hours, were given, resulting in a median treatment time of 35 days. In the majority of patients the conformal target-splitting technique was used. In 19 patients (63%) two cycles of induction chemotherapy were given. The median follow-up time of survivors is 72 months (range, 62-74 months).

RESULTS

We found Grade 1, 2 and 3 acute esophageal toxicity in 11 patients (37%), 2 patients (7%), and 2 patients (7%), respectively. Grade 2 acute pneumonitis was seen in 2 patients (7%). No late toxicity greater than Grade 1 was observed. The actual overall survival rates at 2 and 5 years are 63% and 23%, respectively; the median overall survival, 27.7 months. In 9 patients a local failure occurred, 7 of them presenting initially with an atelectasis without availability of 18-fluorodeoxyglucose-positron emission tomography staging at that time. In 4 patients recurrence occurred regionally.

CONCLUSIONS

This Phase I/II trial with long-term follow-up shows low toxicity with promising results for survival and locoregional tumor control.

Amphotericin B lozengers: prophylaxis for esophagitis in thoracic radiotherapy: a prospective study

BACKGROUND AND PURPOSE

Esophagitis is an important side effect in thoracic radiotherapy, no preventive drug therapy has been established yet. The aim of the present study was to prospectively evaluate the effectiveness of prophylactic antimycotic treatment with amphotericin B lozengers.

PATIENTS AND METHODS

40 consecutive patients with high-dose thoracic radiotherapy for lung cancer were investigated in a nonrandomized study. 20 patients receiving a median maximal esophageal dose of 67 Gy (range 61-80 Gy) were treated with amphotericin B lozengers four times daily from day 8 to the end of radiotherapy. Another 20 patients with a lower median maximal esophageal dose of 60 Gy (range 51-67.5 Gy) constituted the control group. Length of the irradiated esophagus and dose-length indices were evaluated. Side effects were prospectively scored according to the RTOG/EORTC criteria. There was a trend toward higher esophageal volumes in the prophylaxis group; furthermore, patients in this group were older, had a worse median Karnofsky Index and had more often received induction chemotherapy.

RESULTS

In the prophylaxis group, 15 patients remained free from esophagitis and five patients developed esophagitis grade 1. In the control group, four patients remained free from symptoms, 14 patients showed esophagitis grade 1 and two patients grade 2. The difference between the two groups was statistically significant (p < 0.05). The start of symptoms was delayed in the prophylaxis group in comparison to the control group: day 21 (median, range 14-44) and day 18 (median, range 10-32) respectively. Amphotericin B lozengers were tolerated without side effects by all patients.

CONCLUSION

Prophylactic administration of amphotericin B lozengers seems to effectively prevent radiation-induced esophagitis.