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CT Imaging Findings after Stereotactic Radiotherapy for Liver Tumors.

Brook OR, Thornton E, Mendiratta-Lala M, Mahadevan A, Raptopoulos V, Brook A, Najarian R, Sheiman R, Siewert B - Gastroenterol Res Pract (2015)

Bottom Line: Partial response (>30% decrease in long diameter) was seen in 25/36 (69%) HCCs, 14/25 (58%) metastases, and 7/7 (100%) of CCCs.Conclusion.Prominent halo of delayed enhancement of the adjacent liver is frequent finding.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215, USA.

ABSTRACT
Purpose. To study radiological response to stereotactic radiotherapy for focal liver tumors. Materials and Methods. In this IRB-approved, HIPAA-compliant study CTs of 68 consecutive patients who underwent stereotactic radiotherapy for liver tumors between 01/2006 and 01/2010 were retrospectively reviewed. Two independent reviewers evaluated lesion volume and enhancement pattern of the lesion and of juxtaposed liver parenchyma. Results. 36 subjects with hepatocellular carcinoma (HCC), 25 with liver metastases, and seven with cholangiocarcinoma (CCC) were included in study. Mean follow-up time was 5.6 ± 7.1 months for HCC, 6.4 ± 5.1 months for metastases, and 10.1 ± 4.8 months for the CCC. Complete response was seen in 4/36 (11.1%) HCCs and 1/25 (4%) metastases. Partial response (>30% decrease in long diameter) was seen in 25/36 (69%) HCCs, 14/25 (58%) metastases, and 7/7 (100%) of CCCs. Partial response followed by local recurrence (>20% increase in long diameter from nadir) occurred in 2/36 (6%) HCCs and 4/25 (17%) metastases. Liver parenchyma adjacent to the lesion demonstrated a prominent halo of delayed enhancement in 27/36 (78%) of HCCs, 19/21 (91%) of metastases, and 7/7 (100%) of CCCs. Conclusion. Sustainable radiological partial response to stereotactic radiotherapy is most frequent outcome seen in liver lesions. Prominent halo of delayed enhancement of the adjacent liver is frequent finding.

No MeSH data available.


Related in: MedlinePlus

Image capture from stereotactic radiotherapy planning session, showing concentration of radiation dose to the tumor with much smaller but still significant amount of radiation delivered to the surrounding liver.
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fig1: Image capture from stereotactic radiotherapy planning session, showing concentration of radiation dose to the tumor with much smaller but still significant amount of radiation delivered to the surrounding liver.

Mentions: Stereotactic radiotherapy is considered an effective palliative treatment for HCC, metastases, and cholangiocarcinoma [4–9, 14]. In our study population of primary HCC, cholangiocarcinoma, and metastatic disease, the most frequent pattern of response was a decrease in lesion volume that was most pronounced in the first four months, followed by continuous but slower decrease in lesion volume. The nonenhancing portion of the lesion increased to a maximum within the first 3 months after treatment and did not change significantly over the follow-up period unless a recurrence occurred. In rare cases a complete response of a lesion can occur (11% in HCC and 4% of cholangiocarcinoma). Our clinical results from stereotactic radiotherapy are in agreement with previously published phase I/II studies [15, 16] and more recent small series of 25 patients with HCC [5] and 17 patients with variety of liver lesions [4] in which local control was seen in 82–95% of cases, as well as with larger more recent series [17–19]. We have not observed a significant liver toxicity, similar to the prior studies [20–22]. A striking feature that we noted in the majority of the cases was a halo of hyperdensity in the liver surrounding the treated lesion on the portal venous and delayed phases. In two cases of hepatocellular carcinoma, a histopathological correlate was available, with explants evaluated 6 and 7 months after the radiotherapy treatment. The pathology in the areas adjacent to the treated lesions showed findings of fibrosis consistent with postradiation treatment changes. Fibrosis is known to show progressive enhancement that peaks on the delayed/portal venous phase, for example, in the case of confluent hepatic fibrosis [23]. As can be seen in a stereotactic radiotherapy planning session (Figure 1), the liver surrounding the treated lesion is also irradiated, albeit with a smaller dose. Radiation induced injury to the liver has been described previously. As early as in 1965, Ingold et al. [24] reported radiation hepatitis in a cohort of patients treated for gynecological malignancy with whole abdomen external beam radiation. Further studies with histopathologic correlation [25, 26] showed that radiation-induced liver disease has two phases: acute phase occurring within 3 months after exposure with sinusoidal congestion, hyperemia, and diffuse fatty infiltration corresponding to hypodensity of the surrounding liver as seen in our cases [27]. As shown in a histopathological study by Lewin and Millis [28], portal tracts fibrosis and disorganization of the lobular architecture without sinusoidal congestion occur in a later chronic phase. In our cohort this corresponded to enhancement on the delayed/portal venous phase images, which is typical for fibrosis. The differentiation of types of enhancement abutting a lesion is important as a diffuse delayed phase enhancement is more likely a response to radiation fibrosis and should not be misinterpreted as locally recurrent tumor enhancement.


CT Imaging Findings after Stereotactic Radiotherapy for Liver Tumors.

Brook OR, Thornton E, Mendiratta-Lala M, Mahadevan A, Raptopoulos V, Brook A, Najarian R, Sheiman R, Siewert B - Gastroenterol Res Pract (2015)

Image capture from stereotactic radiotherapy planning session, showing concentration of radiation dose to the tumor with much smaller but still significant amount of radiation delivered to the surrounding liver.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4499630&req=5

fig1: Image capture from stereotactic radiotherapy planning session, showing concentration of radiation dose to the tumor with much smaller but still significant amount of radiation delivered to the surrounding liver.
Mentions: Stereotactic radiotherapy is considered an effective palliative treatment for HCC, metastases, and cholangiocarcinoma [4–9, 14]. In our study population of primary HCC, cholangiocarcinoma, and metastatic disease, the most frequent pattern of response was a decrease in lesion volume that was most pronounced in the first four months, followed by continuous but slower decrease in lesion volume. The nonenhancing portion of the lesion increased to a maximum within the first 3 months after treatment and did not change significantly over the follow-up period unless a recurrence occurred. In rare cases a complete response of a lesion can occur (11% in HCC and 4% of cholangiocarcinoma). Our clinical results from stereotactic radiotherapy are in agreement with previously published phase I/II studies [15, 16] and more recent small series of 25 patients with HCC [5] and 17 patients with variety of liver lesions [4] in which local control was seen in 82–95% of cases, as well as with larger more recent series [17–19]. We have not observed a significant liver toxicity, similar to the prior studies [20–22]. A striking feature that we noted in the majority of the cases was a halo of hyperdensity in the liver surrounding the treated lesion on the portal venous and delayed phases. In two cases of hepatocellular carcinoma, a histopathological correlate was available, with explants evaluated 6 and 7 months after the radiotherapy treatment. The pathology in the areas adjacent to the treated lesions showed findings of fibrosis consistent with postradiation treatment changes. Fibrosis is known to show progressive enhancement that peaks on the delayed/portal venous phase, for example, in the case of confluent hepatic fibrosis [23]. As can be seen in a stereotactic radiotherapy planning session (Figure 1), the liver surrounding the treated lesion is also irradiated, albeit with a smaller dose. Radiation induced injury to the liver has been described previously. As early as in 1965, Ingold et al. [24] reported radiation hepatitis in a cohort of patients treated for gynecological malignancy with whole abdomen external beam radiation. Further studies with histopathologic correlation [25, 26] showed that radiation-induced liver disease has two phases: acute phase occurring within 3 months after exposure with sinusoidal congestion, hyperemia, and diffuse fatty infiltration corresponding to hypodensity of the surrounding liver as seen in our cases [27]. As shown in a histopathological study by Lewin and Millis [28], portal tracts fibrosis and disorganization of the lobular architecture without sinusoidal congestion occur in a later chronic phase. In our cohort this corresponded to enhancement on the delayed/portal venous phase images, which is typical for fibrosis. The differentiation of types of enhancement abutting a lesion is important as a diffuse delayed phase enhancement is more likely a response to radiation fibrosis and should not be misinterpreted as locally recurrent tumor enhancement.

Bottom Line: Partial response (>30% decrease in long diameter) was seen in 25/36 (69%) HCCs, 14/25 (58%) metastases, and 7/7 (100%) of CCCs.Conclusion.Prominent halo of delayed enhancement of the adjacent liver is frequent finding.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215, USA.

ABSTRACT
Purpose. To study radiological response to stereotactic radiotherapy for focal liver tumors. Materials and Methods. In this IRB-approved, HIPAA-compliant study CTs of 68 consecutive patients who underwent stereotactic radiotherapy for liver tumors between 01/2006 and 01/2010 were retrospectively reviewed. Two independent reviewers evaluated lesion volume and enhancement pattern of the lesion and of juxtaposed liver parenchyma. Results. 36 subjects with hepatocellular carcinoma (HCC), 25 with liver metastases, and seven with cholangiocarcinoma (CCC) were included in study. Mean follow-up time was 5.6 ± 7.1 months for HCC, 6.4 ± 5.1 months for metastases, and 10.1 ± 4.8 months for the CCC. Complete response was seen in 4/36 (11.1%) HCCs and 1/25 (4%) metastases. Partial response (>30% decrease in long diameter) was seen in 25/36 (69%) HCCs, 14/25 (58%) metastases, and 7/7 (100%) of CCCs. Partial response followed by local recurrence (>20% increase in long diameter from nadir) occurred in 2/36 (6%) HCCs and 4/25 (17%) metastases. Liver parenchyma adjacent to the lesion demonstrated a prominent halo of delayed enhancement in 27/36 (78%) of HCCs, 19/21 (91%) of metastases, and 7/7 (100%) of CCCs. Conclusion. Sustainable radiological partial response to stereotactic radiotherapy is most frequent outcome seen in liver lesions. Prominent halo of delayed enhancement of the adjacent liver is frequent finding.

No MeSH data available.


Related in: MedlinePlus