[Adjuvant contact radiotherapy for conjunctival malignancies: Preliminary results of a series of 14 patients treated with the Papillon 50 machine]

PURPOSE

To evaluate the results of an adjuvant contact irradiation using 50kV photons after resection of conjunctival malignancies.

MATERIALS AND METHOD

From 2012 to 2014, 14 patients (male: nine; female: five) have been treated by contact irradiation after resection of a malignant tumor of the conjunctiva (melanoma: five patients; malignant fibrous histiocytoma: one patient; carcinoma: eight patients) The treatment was performed using the Papillon 50 machine (Ariane). Three to four sessions were delivered, each giving a dose of 10Gy. The median follow-up in survivors was 33 months.

RESULTS

The tolerance was good. A cataract was seen in one patient, and a moderate eye dryness in one. There was no corneal ulcer. One patient died of intercurrent disease. One patient with carcinoma recurred locally.

CONCLUSION

Adjuvant contact radiotherapy provides a good local control after resection of conjunctival malignancies (melanoma, malignant histiocytofibroma, carcinoma). Thanks to its precision, this technique is well tolerated with a low rate of complications. Furthermore, it is delivered on an ambulatory basis.

Twin machines validation for VMAT treatments using electronic portal-imaging device: a multicenter study

Purpose

To verify the accuracy of volumetric arc therapy (VMAT) using the RapidArc™ device when switching patients from one single linear accelerator (linac) to a paired energy and mechanics "twin" linac without reoptimization of the original treatment plan.

Patients and Methods

Four centers using 8 linacs were involved in this study. Seventy-four patients previously treated with the 6MV photon RapidArc™ technique were selected for analysis, using 242 measurements. In each institution, all patients were planned on linac A, and their plans were verified both on linac A and on the twin linac B. Verifications were done using the amorphous silicium electronic portal imager (EPID) of the linacs and were analyzed with the EpiQa software (Epidos, Bratislavia, Slovakia). The gamma index formalism was used for validation with a double threshold of 3 % and 3 mm with a measurement resolution of 0.39 mm/pixel, and a smoothed resolution of approximately 2.5 mm.

Results

The number of points passing the gamma criteria between the measured and computed doses was 94.79 ± 2.57 % for linac A and 94.61 ± 2.46 % for linac B. Concerning the smoothed measurement analysis, 98.67 ± 1.26 % and 98.59 ± 1.20 % points passing the threshold were obtained for linacs A and B, respectively.

The difference between the 2 dose matrices acquired on the EPID was very small, with 99.92 ± 0.06 % of the points passing the criteria.

Conclusion

For linacs sharing the same mechanical and energy parameters, this study tends to indicate that patients may be safely switched from treatment with one linac to treatment with its twin linac using the same VMAT plan.

Feasibility of high-dose three-dimensional radiation therapy in the treatment of localised non-small-cell lung cancer

PURPOSE

Chemoradiotherapy is the standard treatment of inoperable and/or non-resectable IIIA/B non-small-cell lung cancer (NSCLC). Aware of the necessity to increase local control in locally advanced NSCLC, we analyzed the feasibility of high-dose three-dimensional conformal radiation therapy (3D-CRT) in the treatment of localised NSCLC.

PATIENTS AND METHODS

We undertook a retrospective analysis of consecutive patients with non-resectable NSCLC treated with high-dose (74Gy) standard-fractionation 3D-CRT, with particular attention to the relationship between lung and heart radiation-induced toxicities.

RESULTS

Fifty patients (41 males, 9 females) were included. A total of 35 (70%) patients received the planned total dose of 74Gy. Patients irradiated to inferior doses interrupted the treatment because of limiting toxicities. Induction and concurrent chemotherapy was delivered to 39 (78%) and 14 (28%) patients, respectively. Eight (16%) patients experienced grade 3-4 acute lung toxicity, all of them having a history of pulmonary disease, a FEV1 below 1.6 L, and a lung V(20) of at least 25%. Three (6%) patients were deemed to experience radiation-induced cardiac toxicity.

CONCLUSIONS

This study assesses the feasibility of delivering a total dose of 74 Gy combined with chemotherapy in locally advanced NSCLC. High lung and heart V(20) increases the risk of radiation-induced lung and cardiac toxicity, the later being highly difficult to precisely assess, as late deaths are rarely documented, and responsibility of the treatment might be often underestimated. The precise evaluation of cardiac condition may be helpful to spare fragile patients from potentially toxic effects of high-dose radiation, especially in controlled trials.

Tolérance et efficacité de la radiothérapie de conformation en cas de carcinome hépatocellulaire chez le patient cirrhotique. Résultats de l'essai de phase II RTF1

PURPOSE

While some patients presenting with hepatocellular carcinoma (HCC) benefit from curative therapies (transplantation, surgery, percutaneous ablation), others are only candidates for palliative options such as chemoembolization or symptomatic care. Although conventional external-beam radiotherapy of the liver is regarded as little efficient and potentially toxic in cirrhotic patients, 3-dimensional conformal radiotherapy (CRT), by decreasing the amount of normal liver included in the radiation portal, allows dose escalation to occur without increasing the risk of radiation-induced hepatitis. This trial was designed to assess the efficacy and tolerance of CRT for small-size HCC in cirrhotic patients.

PATIENTS AND METHODS

Prospective phase II trial including stage A/B cirrhotic patients with small-size HCC not suitable for curative treatments; CRT consisted in a standard fractionation radiation, with a total dose of 66 Gy.

RESULTS

Twenty-seven patients were included, 15 of whom had previously been treated for HCC; mean age was 68. Among the 23 assessable patients, 18 (78%) presented with complete response, 3 (13%) with partial response, and 2 with no response. Acute complications occurred in 24 patients, and were mainly acceptable (grade 1/2: 22 patients, grade 3/4: 11 patients, 4 (15%) of whom had clinical and/or hematological toxicities). Only 2 (9%) grade 3/4 clinical and/or hematological late toxicities are reported.

CONCLUSION

CRT is a non-invasive curative technique highly suitable for small-size HCC in cirrhotic patients; further investigations are needed to compare it to the other available treatments, and to integrate it into the curative therapeutic algorithm of HCC.

[Chemoradiation for pancreatic adenocarcinoma]

Surgery remains the cornerstone treatment for pancreatic adenocarcinoma. However, 5% to 20% of tumors only are regarded as resectable, and, among them, only few benefit from an histological complete resection, major survival parameter. These data explain the overall poor prognosis of this disease, with a respectively 20% and 5% 1- and 5-year survival rates. These results justify an adjuvant or neoadjuvant therapeutic approach, mainly based on concurrent chemoradiation, with and without surgery. This paper reviews the different therapeutic approaches of non metastatic pancreatic adenocarcinoma.

Simulating the amplification of orbital forcing by ocean feedbacks in the last glaciation

According to Milankovitch theory, the lower summer insolation at high latitudes about 115,000 years ago allowed winter snow to persist throughout summer, leading to ice-sheet build-up and glaciation. But attempts to simulate the last glaciation using global atmospheric models have failed to produce this outcome when forced by insolation changes only. These results point towards the importance of feedback effects-for example, through changes in vegetation or the ocean circulation-for the amplification of solar forcing. Here we present a fully coupled ocean-atmosphere model of the last glaciation that produces a build-up of perennial snow cover at known locations of ice sheets during this period. We show that ocean feedbacks lead to a cooling of the high northern latitudes, along with an increase in atmospheric moisture transport from the Equator to the poles. These changes agree with available geological data and, together, they lead to an increased delivery of snow to high northern latitudes. The mechanism we present explains the onset of glaciation-which would be amplified by changes in vegetation-in response to weak orbital forcing.