CONVENTIONAL 4-FIELD PELVIC RADIOTHERAPY TECHNIQUE WITHOUT COMPUTED TOMOGRAPHY-TREATMENT PLANNING IN CANCER OF THE CERVIX - POTENTIAL GEOGRAPHIC MISS AND ITS IMPACT ON PELVIC CONTROL
Ry. Kim et al., CONVENTIONAL 4-FIELD PELVIC RADIOTHERAPY TECHNIQUE WITHOUT COMPUTED TOMOGRAPHY-TREATMENT PLANNING IN CANCER OF THE CERVIX - POTENTIAL GEOGRAPHIC MISS AND ITS IMPACT ON PELVIC CONTROL, International journal of radiation oncology, biology, physics, 31(1), 1995, pp. 109-112
Citations number
18
Categorie Soggetti
Oncology,"Radiology,Nuclear Medicine & Medical Imaging
Purpose: To evaluate the impact of inadequate margins on pelvic contro
l using the conventional four-field pelvic portals without computed to
mography (CT)-treatment planning. Methods and Materials: Between 1986
and 1991, 34 patients with invasive cancer of the cervix were eligible
for outcome study of conventional four-field radiation therapy (10 St
age I, 16 Stage II, 8 Stage III). The eligibility for this study inclu
des four-field pelvic technique, definitive radiation therapy, and dia
gnostic CT scan of the pelvis. For this study, an inadequate margin is
arbitrarily defined as less than or equal to 1.0 cm of normal tissue
around the CT-defined tumor volume. Results: All 34 patients had adequ
ate margins for anterio-posterior/posterio-anterior portals. However,
19 patients had an inadequate margin at the posterior border (S2-S3 in
terspace) and/or custom-shaped rectal block for lateral pelvic portals
. Two patients had inadequate margins at the anterior border (level of
symphysis pubis) due to an enlarged uterus. With a median follow-up o
f 36 months, pelvic control for adequate margins and inadequate margin
s was 100% and 71% for Stage IB disease and 88% and 50% for Stage IIB
disease, respectively. However, pelvic control for Stage IIIB disease
was 50% for both groups. There was no difference in total dose to poin
t A or point B between the two groups.Conclusion: Our preliminary data
show higher local failure in patients with an inadequate margin. For
four-field pelvic radiation therapy, we strongly recommend CT-treatmen
t planning. Otherwise, anterio-posterior/posterio-anterior pelvic ther
apy is the most reliable treatment for cancer of the uterine cervix.