gms | German Medical Science

48th Meeting of the Particle Therapy Co-Operative Group

Particle Therapy Co-Operative Group (PTCOG)

28.09. - 03.10.2009, Heidelberg

Proton treatment of prostate cancer in the presence of unilateral hip replacement

Meeting Abstract

  • M. Fitzek - Midwest Proton Radiotherapy Institute, Bloomington, IN, USA
  • K. Shahnazi - Midwest Proton Radiotherapy Institute, Bloomington, IN, USA
  • J. Simmons - Midwest Proton Radiotherapy Institute, Bloomington, IN, USA
  • A. Thornton - Midwest Proton Radiotherapy Institute, Bloomington, IN, USA

PTCOG 48. Meeting of the Particle Therapy Co-Operative Group. Heidelberg, 28.09.-03.10.2009. Düsseldorf: German Medical Science GMS Publishing House; 2009. Doc09ptcog060

DOI: 10.3205/09ptcog060, URN: urn:nbn:de:0183-09ptcog0608

Published: September 24, 2009

© 2009 Fitzek et al.
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Outline

Text

Purpose: Patients with unilateral hip replacements are currently not treated with protons at most proton facilities, secondary to the inability to deliver a lateral field through the hip prosthesis. We describe our technique of proton treatment of prostate cancer in those patients.

Material and methods: Five patients with unilateral hip replacement were treated at the Midwest Proton Radiotherapy Institute in 2008–2009. An analysis of their plans forms the basis of this report. All patients had low or intermediate risk prostate cancer. Median prostate gland size on planning CT was 76 ml (range 23 to 81 ml). We used a standardized bladder filling regimen, single prostate marker insertion, and a rectal balloon filled with 60 cc of fluid in all patients.

Results: Patients were treated with a combination of a lateral proton field through the natural hip and one or two anterior oblique fields. The oblique fields were coplanar and mostly 35 to 40 degree angled anteriorly from the side of the replaced hip plus the side of the natural hip. The prescription doses to the prostate were 70.2 GyE (Gray-Equivalent, one patient), 75.6 GyE (1 patient), and 79.2 GyE (3 patients). The seminal vesicle was treated in all patients to 50.4 GyE. Dose constraints of not more than 30% of the anterior rectal wall receiving more than 70.2 GyE and not more than 10% of it receiving more than 77.4 GyE were met. Not more than 20% of the bladder received more than 60 GyE; only in one patient with a small bladder we accepted 30% receiving 60 GyE or more. We found good reproducibility of the plan on repeated CT scans in each patient. Treatment was well tolerated, comparable to the conventional technique with lateral fields.

Conclusion: It is feasible to treat prostate cancer with protons in the presence of unilateral hip replacement by modifying the treatment approach, substituting the lateral field from the side of the replaced hip with 2 anterior oblique fields.