Comparison of Dosimetric Parameters Between Field in Field and Conformal Radiation Therapy Techniques in Early Stage of Left Breast Cancer Patients

Abstract

Background: Breast cancer is the most prevalent cancer in women all over the world. The most common and effective treatment for the early stage of breast cancer patients is breast conserving surgery (BCS) followed by radiotherapy. Objectives: The aim of this study is to evaluate and compare the dosimetric parameters of three-dimensional conformal radiation therapy (3D-CRT), using virtual wedge and field in field (FIF) techniques for patients having left breast cancer in early stages. Methods: Twenty-four patients with left breast cancer participated in this study. They were divided into thr3ee categories (small, medium, and large) based on breast volume: ≤ 1500 cc small, 1500-2000 cc medium, and > 2000 cc large. Two treatment planning techniques were generated for each patient by prowess treatment planning system. The following parameters were compared: Maximum, minimum, and mean dose in planning target volume (PTV), homogeneity (HI) and conformity indexes (CI), percentage of volume receiving greater than 107% of the prescribed dose (hot spots) and less than 95% of the prescribed dose (cold spots), and total monitor unit (MU) and doses received to organs at risks (OARs) such as heart and left lung. The mean values were compared using student's t-test. Results: The FIF technique reduced either the maximum dose in PTV or hot spots in all groups significantly (P < 0.05). Conformity index and cold spots in conformal technique were significantly better than FIF technique in all groups (P < 0.05). Other parameters such as MU, HI, and doses received by OARs did not show any significant difference between two methods in all groups (P > 0.05). Conclusions: It is recommended that two techniques can be combined and used together to cover their weak points. Also, it seems that if there is no equipment of intensity modulated radiation therapy (IMRT) techniques such as FIF in some centers, conformal technique by using virtual wedge is a proper alternative.

Assessment of Field-in-Field, 3-Field, and 4-Field Treatment Planning Methods for Radiotherapy of Gastro-Esophageal Junction Cancer

“…Compared with 3D CRT, the FIF technique uses simple (i.e., non-wedged) beams and can be performed at each center equipped with MLCs. Also, the FIF technique delivers excellent dose coverage for PTV [13,14,23,32] and acceptable performance for protecting OARs during radiotherapy for esophageal, pancreatic, and early-stage breast cancers [9,14,29,33]. However, no study has been conducted on the feasibility of this technique in patients with GE junction cancer.…”

Dosimetric evaluation of 3 and/or 4 field radiation therapy of breast cancers: clinical experience

“…Adequate target coverage is associated with tumour control which leads to improve biochemical relapse-free survival, cancer progression-free survival and cancer-specific survival. Several studies [8][9][10][11][12][13][14][15][16]20,22,23,26,27,30 have reported similar PTV_eval coverage for breast cancer patients. Tanaka et al 16 investigated the FIF technique with lung blocks for breast radiotherapy and reported V 95% and V 100% of 93•2 and 62•7% for patients treated with the FB technique.…”

“…When treating the intact breast or chest-wall for low-risk early stage patients, a pair of opposed tangential fields are usually employed. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] However for high-risk patients with node positive disease or are at greater risk of nodal metastasis, radiation therapy will involve treatment of the intact breast or chestwall as well as the regional lymph nodes. This is achieved using two tangential fields to treat the intact breast or chest-wall and an anterior and sometimes opposed posterior fields to treat the regional lymph nodes in the upper axillary and supraclavicular regions.…”

“…Several studies have reported that using IMRT, VMAT, FIF or the hybrid technique to treat the breast and regional lymph nodes have greater target coverage, reduced hotspots and reduced doses to the organs at risk (OAR) compared to conventional treatment with wedges. 4,6,7,10,11,14,18,23,[27][28][29][30] Some studies 6,9,[12][13][14]16,17,21,26,31 that have evaluated and compared the dosimetric parameters of three-dimensional conformal radiation therapy using FIF technique have reported significant maximum dose and hotspots reduction, improved dose coverage and a more homogenous distribution within the target. Other studies 6,8,11,12,15,18,26,27 have also used the hybrid technique for breast radiotherapy and observed similar improved dose coverage, reduced hotspots in the target and less dose to the OARs.…”