Role of Definitive Radiation Therapy in Carcinoma of Unknown Primary in the Abdomen and Pelvis
Objectives
Carcinoma of unknown primary (CUP) in the abdomen
and pelvis is a heterogeneous group of cancers with no standard
treatment. Considered by many to be incurable, these patients are often
treated with chemotherapy alone. In this study, we determined the
effectiveness of radiation therapy in combination with chemotherapy in
patients with CUP in the abdomen and pelvis.
Patients and Methods
Medical
records were reviewed for 37 patients with CUP treated with radiation
therapy for disease located in the
soft tissues and/or
nodal basins of
the abdomen and pelvis at the University of Texas M.D. Anderson Cancer
between 2002 and 2009. All patients underwent chemotherapy, either
before or concurrent with radiation therapy. Patients were selected for
radiation therapy on the basis of histologic type, disease extent, and
prior therapy response. Twenty patients underwent definitive radiation
therapy (defined as radiation therapy targeting all known disease sites
with at least 45 Gy) and 17 patients underwent palliative radiation
therapy. Only 6 patients had surgical resection of their disease.
Patient and treatment characteristics were extracted and the endpoints
of local disease control, progression-free survival (PFS), overall
survival (OS), and treatment-related toxicity incidence were analyzed.
Results
The
2-year PFS and OS rates for the entire cohort were
32% and 57%,
respectively. However, in patients treated with definitive radiation
therapy, the rates were
48% and 76%, and 7 patients lived more than 3
years after treatment with no evidence of disease progression.
Nevertheless,
radiation-associated toxicity was significant in this
cohort, as
40% experienced
Grade 2 or higher late toxicities.
Conclusions
The
use of definitive radiation therapy should be considered in selected
patients with CUP in the soft tissues or nodal basins of the abdomen and
pelvis.
