Comparative study of dosimetry and acute toxicity of 3d-Crt (3Dimensional Conformal Radiotherapy), IMRT (Intensity -Modulated Radiation Therapy) and Helical Tomotherapy for treatment of breast cancer

Introduction:

Breast cancer is the second most common cancer in the world.  Breast cancer ranks as the fifth cause of the death from cancer overall and it is the most frequent cause of cancer death in women in less developed regions and the second cause of cancer deaths in most developed regions. It is the major cause of morbidity and mortality among females ranking number one among females in Indian metropolitan cities like Delhi, Kolkata, Pune and Thiruvananthapuram, Bangalore and Mumbai and in Northeast, whereas in rural areas such Barshi it still hold a second position.

In India, Age Adjusted rates of breast cancer is found to be 25.8 whereas in UK it is 95 per 1 lakh women, but the mortality rate of India is 12.7 per lakh whereas it is 17.1 per lakh in UK.

Breast -conserving surgery followed by radiation therapy to the intact breast is now clearly established as the most acceptable standard of care for the majority of women with early stage invasive breast cancer.  Recommended techniques for breast conservation treatment are wide local excision of the primary tumour, preferably with clear margins, axillary lymph node dissection, and breast irradiation (45 to 50 Gy), usually with a boost (10 to 20 Gy, depending on tumour size and status of the surgical margins).

Need for the study:

1. Various studies have shown inconsistent findings in regard to normal organ sparing by 3DCRT, IMRT and Helical Tomotherapy.

2. The purpose of the study is to know if there is any  significant difference in target coverage, doses received by organs at risk and acute toxicities between 3DCRT, IMRT and Helical Tomotherapy while treating breast cancer.

 Research Hypothesis:

Helical Tomotherapy is superior to 3D-CRT and IMRT in target coverage and sparing organs at risk.

Aims:

To compare the dosimetric parameters with respect to planning target volume and organs at risk between 3DCRT, IMRT and Helical Tomotherapy in patients with Breast Carcinoma and correlation with acute toxicities.

Objectives:

To compare the patients planned with Helical Tomotherapy, IMRT and 3 -D CRT with respect to doses received by

Planned Target Volume (PTV)

Organs at risk

To detect incidence and grade of acute toxicities in all 3 techniques

 Materials:

Patient Particulars – Name, age, address.

Patient History – Patient presenting complains, family history.

Clinical examination.

Dosimetric Parameters of the treatment plan.

Details of investigations done during treatment. (eg. Blood tests.)

Target and Organs at Risk Delineation: Gross tumour volume (GTV), Clinical target Volume (CTV), Planning target volume (PTV) and Organs at risk.

RTOG guidelines will be followed for delineation of target volumes and organs at risk.

All Patients will be treated with hypofractionation 40-42.6 Gy in 15-16 fractions followed by 10-16Gy in 5-8 fractions.

Acute toxicities eg. Skin reaction, dysphagia etc. will be monitored during treatment, and at 4-6 weeks and 3 months post radiation treatment . Toxicities will be graded according to the RTOG Acute toxicity criteria.

Statistics analysis Plan:

The variables would describe using mean or median with their respective SD or IQR (inter quartile range). Comparison of variables between treatment techniques would be done using one-way ANOVA (Analysis of variance) fixed effect model or Kurskal Wallis, based the normality of the data.  Correlations (Pearson’s or Spearman Ranked Correlation) would be attempted to explore additional relationships in the data collected.  All test would be two-tailed and results would be deemed significant if p values are 0.05 or lower. Confidence intervals would be presented where appropriate.