Impact of total marrow/lymphoid irradiation dose to the intestine on graft-versus-host disease in allogeneic hematopoietic stem cell transplantation for hematologic malignancies

Background and purpose

Graft-versus-host disease (GvHD) is a leading cause of non-relapse mortality in patients undergoing allogeneic hematopoietic stem cell transplantation. The Perugia Bone Marrow Transplantation Unit designed a new conditioning regimen with total marrow/lymphoid irradiation (TMLI) and adaptive immunotherapy. The present study investigated the impact of radiotherapy (RT) doses on the intestine on the incidence of acute GvHD (aGvHD) in transplant recipients, analyzing the main dosimetric parameters.

Materials and methods

Between August 2015 and April 2021, 50 patients with hematologic malignancies were enrolled. All patients underwent conditioning with TMLI. Dosimetric parameters (for the whole intestine and its segments) were assessed as risk factors for aGvHD. The RT dose that was received by each intestinal area with aGvHD was extrapolated from the treatment plan for each patient. Doses were compared with those of the whole intestine minus the affected area.

Results

Eighteen patients (36%) developed grade ≥2 aGvHD (G2 in 5, G3 in 11, and G4 in 2). Median time to onset was 41 days (range 23-69 days). The skin was involved in 11 patients, the intestine in 16, and the liver in 5. In all 50 TMLI patients, the mean dose to the whole intestine was 7.1 Gy (range 5.07-10.92 Gy). No patient developed chronic GvHD (cGvHD). No dosimetric variable emerged as a significant risk factor for aGvHD. No dosimetric parameter of the intestinal areas with aGvHD was associated with the disease.

Conclusion

In our clinical setting and data sample, we have found no clear evidence that current TMLI dosages to the intestine were linked to the development of aGvHD. However, due to some study limitations, this investigation should be considered as a preliminary assessment. Findings need to be confirmed in a larger cohort and in preclinical models.

High-dose-rate brachytherapy with surface applicator in penile cancer

PURPOSE

An alternative to surgery for penile cancer is radiation therapy which is administered with external beam techniques and/or brachytherapy (BT) either interstitial or using a surface applicator. Here we report our experience in penile cancer patients treated with high-dose-rate (HDR)-BT with the surface technique, analyzing dosimetric parameters and clinical outcomes.

METHODS AND MATERIALS

Between June 2016 and December 2019, 7 patients with squamous cell carcinoma of the penis received HDR-BT by means of customized applicators that were constructed using a 3D printer or thermoplastic mask. The total dose was 57 Gy in 19 fractions.

RESULTS

Median clinical target volume percentage receiving 95%, 125%, and 150% of the prescribed dose were 93.1% (range 92.2-98.5), 12% (range 7.4-32.2), and 0.24% (range 0-10.8), respectively. Median urethral volumes receiving 90% and 115% of the prescribed dose were 40.2% (range 21.0-83.8) and 0% (range 0-1), respectively. All patients achieved complete remission. No patient developed G3 or G4 acute or late toxicities. No patient experienced urethral stenosis.

CONCLUSIONS

Surface HDR-BT in penile cancer is feasible and is associated with a high tolerance profile and good outcomes.