Comparative Study of Treatment Response and Toxicity of Four Field Box Technique Versus Two Field Technique External Beam Radiotherapy in Locally Advanced Carcinoma Cervix

Roshani Shrestha; Bibek Acharya

Roshani Shrestha Department of Radiation Oncology, National Academy of Medical Sciences, Kathmandu, Nepal
Bibek Acharya Department of Radiation Oncology, National Academy of Medical Sciences, Kathmandu, Nepal

Keywords: External Beam Radiotherapy, concurrent chemotherapy, locally advanced cervical cancer

Abstract

Introduction: External beam radiotherapy plays a pivotal role in locally advanced carcinoma
cervix. EBRT treats the whole pelvis including the primary tumor along with the regional lymph
nodes. Conventionally, EBRT planning is based on standard bony landmarks using X-rays and can
be delivered by anterior–posterior and posterior–anterior (AP-PA) parallel opposed fields or the
four field box technique. AP-PA field technique provides good coverage to the target volume. Four
field box technique with parallel opposed AP-PA fields and two lateral opposed fields although has
better dose distribution and decrease normal tissue toxicity, is time-consuming. EBRT by AP-PA
two fi eld technique is generally used in our center due to less manpower and resources and huge
load of patients. But, pelvic radiotherapy by 4 field portals has been proven by the trials that it has
better tumor response. So, the objective of this study was to compare the tumor response and
acute hematological and non- hematological toxicities between the two techniques.
Methods: One hundred and twenty patients with diagnosis of carcinoma cervix were enrolled in
this study, sixty assigned in each group. Group A received radiation by AP-PA two field technique
and Group B by 4 field box technique. Chemotherapy regimen was the same for the two groups.
Treatment response and toxicities were evaluated after the completion of treatment and compared
between two groups.
Results: All enrolled patients received planned treatment. The total duration of treatment in both
the groups was 23 days. Loco-regional control with complete remission was 63.3 % in group A
Vs. 73.3% in group B (p= 0.405). Acute toxicities of grade 1 and grade 2 were seen more in group
A compared to group B, nausea (63.3% vs. 56.7% p=0.141), vomiting (13.3% vs. 20% p=0.234),
diarrhea (10% vs. 6.7%), radiation dermatitis (3.3% vs. 0%). Hematological toxicities like anemia,
thrombocytopenia and leucopenia were observed more in group A than group B.
Conclusion: Both two and four field box techniques are equally effective and feasible as statistically
insignificant difference in the response rate and acute toxicities was observed in the two groups.