The Importance of Multi-Parametric MRI, PET/CT, and Biopsy for Identifying and Delineating the Extent of Locally Radiorecurrent Prostate Cancer: A Multi-institutional Analysis of the F-SHARP Clinical Trial

PURPOSE/OBJECTIVE(S)

Up to 50% of clinical recurrences after curative-intent radiation are intraprostatic local radiorecurrences (LRR), with improved detection through the recent incorporation of multi-parametric MRI and PET/CT in workup. Salvage local therapy (SLT) is increasingly being offered, particularly focal SLT to try to reduce toxicity due to prior radiation. Limited data exist on the incremental value of each imaging modality and biopsy in defining LRR. The objective of this study is to compare the findings of MRI, PET/CT and biopsy in patients with LRR prostate cancer, and the impact each modality has on identifying recurrence and defining the extent of prostate involvement.

MATERIALS/METHODS

This is a secondary analysis of 58 patients enrolled on the ongoing F-SHARP phase I/II clinical trial of salvage HDR brachytherapy from 3 institutions who underwent PSMA or fluciclovine PET/CT, MRI, and biopsy prior to enrollment. Recurrent tumor was delineated on each imaging modality and by inclusion of involved regions on biopsy. Descriptive statistics were used to compare the imaging-defined tumor with biopsy findings to assess the congruence between the imaging modalities and generate the percentage of patients with disease involvement on biopsy outside of the image-defined targets.

RESULTS

Initial therapy was conventional/moderately hypofractionated photons in 35 patients, LDR in 13, proton therapy in 7, SBRT in 2, and neutrons in 1. Recurrence Gleason grade groups included 1 (n = 3), 2 (17), 3 (12), 4 (8), 5 (9), and uninterpretable (9). MRI/TRUS sextant + fusion biopsy was performed in 40 patients, TRUS saturation biopsy in 4, and TRUS systematic biopsy in 14. The median number of cores involved and obtained were 6 and 14. The median number of discrete lesions on biopsy in different quadrants of the prostate was 3 (1-6). The median number of discrete lesions seen on MRI was 1 (0-4). MRI did not identity a discrete lesion in 4 patients. The sensitivity of MRI for detection of the LRR was 92.8%. The false negative rate for not detecting the focus of LRR on MRI was 7.2%. 68.4% of patients had biopsy-proven cancer outside of the MRI-defined target. Fluciclovine PET/CT was used in 45 patients, and 13 had PSMA PET/CT. The median number of lesions on PET/CT was 1 (0-2). PET/CT did not identify a discrete lesion in 8 patients. The pooled sensitivity of PET/CT in detecting the focus of LRR was 86.2% (Fluciclovine: 82.2%, PSMA: 100%). PET/CT false negative rate of PET/CT for not detecting the focus of LRR was 13.8% (Fluciclovine: 17.8%, PSMA 0%). 72.41% of patients had biopsy-proven cancer outside of the PET/CT-defined target (Fluciclovine: 77.8%, PSMA: 53.8%).

CONCLUSION

Although mpMRI and PET/CT are valuable tools for identifying LRR and delineating the extent of prostate/SV involvement, a thorough biopsy is mandatory if pursuing focal SLT. Such treatment should optimally be performed on a clinical trial with robust integration of all imaging and histopathologic data.

Modern external beam radiation therapy for refractory dissecting cellulitis of the scalp

BACKGROUND

Dissecting cellulitis of the scalp can be an extremely painful and disfiguring dermatological condition. The associated pain can be severe enough in some cases to require opioid analgesics, and this pain in conjunction with the disfigurement can induce significant emotional distress. Conservative treatments often fail to provide relief. Radiation therapy has been successfully used in the past but with outdated equipment and techniques.

OBJECTIVES

To evaluate the efficacy and toxicity of modern external beam radiation therapy techniques for the treatment of dissecting cellulitis of the scalp.

METHODS

Four patients with intractable dissecting cellulitis of the scalp were treated with electrons or a combination of electrons and photons to the entire scalp. Daily fraction sizes were 2.5 or 3 Gy and initially prescribed to 15-21 Gy. Patients were re-evaluated 3-4 weeks after completion of therapy. Any residual hair growth was treated with additional radiation treatments to ensure full epilation, up to a maximum dose of 35 Gy.

RESULTS

Rapid resolution of pain was seen in all patients with pain. Regression of nodules and decreased discharge was seen in all patients following treatment and cosmesis was subjectively improved. No long-term toxicity has been observed.

CONCLUSIONS

Using modern techniques and equipment, radiation therapy appears to be a reasonable option for patients with severe/refractory dissecting cellulitis of the scalp. Acute effects are mild and well tolerated. Aside from alopecia, which was present to some extent in all patients before treatment, no long-term complications have been observed.

Phase I study of escalating doses of low-dose-rate, locoregional irradiation preceding Cytoxan-TBI for patients with chemotherapy-resistant non-Hodgkin's or Hodgkin's lymphoma

PURPOSE

In patients in whom bone marrow transplantation (BMT) fails, recurrence often occurs at sites known to have contained disease before initiating BMT. The purpose of this study was to find the maximal tolerable dose of locoregional irradiation (LRT) between 1000 and 2000 cGy that could be integrated with our Cytoxan-total body irradiation (TBI) BMT conditioning regimen in the treatment of lymphoma.

METHODS AND MATERIALS

Patients had Hodgkin's or non-Hodgkin's lymphoma in chemotherapy-refractory relapse. All patients received LRT to a maximum of three sets of fields encompassing either all current or all previously known sites of disease. Cytoxan-TBI consisted of cyclophosphamide 50 mg/kg daily for 4 days followed by TBI of 1200 cGy given in four fractions.

RESULTS

Twenty-one patients were enrolled. Radiation Therapy Oncology Group Grade 3 in-field acute toxicity was observed in 1 patient at each dose level up to 1500 cGy and in 3 of 6 patients receiving 2000 cGy. Clinically evident late toxicities were limited to hypothyroidism and one second malignancy occurring outside the LRT fields.

CONCLUSION

Low-dose-rate, LRT with concurrent Cytoxan-TBI before BMT has acceptable rates of in-field toxicity for doses up to 1500 cGy in five fractions. This regimen safely permits the use of a total combined radiation dose of up to 2700 cGy during 2 weeks, with encouraging in-field response rates in treatment-refractory patients.

Acute and late radiotherapy toxicity in patients with inflammatory bowel disease

PURPOSE

To evaluate the incidence of gastrointestinal complications in patients with inflammatory bowel disease (IBD) receiving radiotherapy (RT) and to identify possibly avoidable factors associated with these complications.

METHODS AND MATERIALS

Twenty-four patients were identified and their records reviewed; all had a history of IBD before receiving RT to fields encompassing some portion of the gastrointestinal tract (Crohn's disease) or to the abdomen or pelvis (ulcerative colitis or IBD not otherwise specified).

RESULTS

Five of 24 patients (21%) experienced Grade > or =3 acute gastrointestinal toxicity; all 5 received concurrent chemotherapy. Two of 24 patients (8%) experienced Grade > or =3 late gastrointestinal toxicity. There were no significant correlations between complications and IBD type, prior IBD-related surgery, use of medications for IBD, or status of IBD.

CONCLUSION

Patients with IBD may have an increased risk for severe acute RT-related gastrointestinal complications that is more modest than generally perceived, because all patients who had Grade > or =3 acute complications in this study had received concurrent chemotherapy (p = 0.04). Further study is needed to assess this risk, as well as the impact of RT on these patients' future gastrointestinal morbidity.

Nonsegmental ventilation-perfusion scintigraphy mismatch after radiation therapy

PURPOSE

This report illustrates the utility of ventilation-perfusion scintigraphy in differentiating radiation pneumonitis from other causes of dyspnea, including pulmonary embolism, heart failure, obstructive tumor, and chronic obstructive pulmonary disease.

METHODS AND RESULTS

A nonsegmental mismatched perfusion abnormality, which exactly conformed to a radiation port, was diagnostic of radiation pneumonitis.

CONCLUSION

In patients with lung tumors presenting with dyspnea, ventilation-perfusion scintigraphy may be useful in diagnosing radiation pneumonitis and effectively excluding other causes of dyspnea.