The aim of this study was to assess the dose received by critical organs (eye, thyroid gland and the shoulder joint) in breast cancer irradiated patients using Day’s method technique and thermo-luminescence dosimeter TLD in addition to involved age group and cancer histological types. The study designed as experimental and retrospective study implies the location of critical organs, back scattered factor, source surface distance, patient’s ages and the histological cancer types. Excel data analysis revealed that: breast cancer has been observed among age groups of 18-23 and 24-29 years old and peaking at 30% among the age groups of 42-47 years old; the common histological types were ductal (57%), lobular (18%) and medullary (10%). The dose% received by critical organs decreased linearly and significantly (R2=0.6) by 5% cm-1, 1.3% cm-1 and 9.7% cm-1 (from supraclavicular) and 1.44% cm-1, 9.86% cm-1 and 1.83% cm-1 (from tangential field) respectively as the distance increase from the field boarder. Out of applied tumor dose (TD=4500 cGy); the critical organs received: 36, 319.5 and 382.5 cGy (Day’s method-anterior supraclavicular) respectively and 58.5, 355.5 and 436.5 cGy (TLD method). And from tangential field they received 13.5, 58.5 and 103 cGy (Day’s method) and 27, 99 and 135 cGy (TLD method). Day’s method generally showed only 0.6% less differs compared to TLD measurement.

The breast consists up of 15–20 lobules of glandular tissue embedded in fat; in mature woman it lies between the 2nd. Rib superiorly and extends to the infra-mammary fold at the level of the 6th-7th. Rrib in the vertical axis, horizontally it extends from the lateral edge of the sternum to the anterior or mid-axillary line. The posterior surface rests on the deep pectoralis fascia, serratus anterior, external oblique abdominal muscles, and the upper rectus sheath. Breast tissue also projects into the axilla as the axillary tail of Spence. As the lymphatic system represents the potential root of cancer spread and accordingly the fact stated by some scholars was that: the length to diameter ratio of axillary lymphadenopathy fall within less than 1.5 cm indicate the malignancy in addition to lymph nodes shape visualized by ultrasound.

Breast cancer is a worldwide disease resulting in many deaths; it represents the second most common cancer in the world, as reported by American Cancer Society that showed about 1.3 million American women are annually diagnosed with BC and about 0.5 million die from the malignancy, while Ravichandran and Al-Zahrani, Ravichandran et al.  investigated the incidence of female breast cancer in the Gulf Cooperation Council (GCC) countries in relation to the established reproductive factors. A total of 4480 breast cancer cases were diagnosed in women during 1998-2002 among GCC country nationals. However, in Saudi Arabia; the epidemiological studies carried out by Ravichandran et al. Al-Qahtani in which they reported that: BCa incidence was 19.8% of all the female cancers detected in the Kingdom it was revealed that the BCa as the second most common malignancy in women in KSA. An earlier report by Saudi National Cancer Registry revealed an increasing proportion of BCa among women of different ages from 10.2% (2000) to 24.3%. Most cases have been presented at late stages for treatment in African countries as well as in Saudi Arabia and some other Arabian countries, which is due to the lack of awareness by women, accessibility to screening methods, and availability of African-based research findings that would influence decision making at the governmental level . However in Sudan, breast cancer has been recorded from 2541 cases in 2000 to 6303 cases in 2010. Among such increasing rate; breast cancer reported as the first top case with an incidence rate of 25.1 per 100,000 as has been estimated by Amany et al.

The efforts of national and international organization as well as the health care institutions have been continuing to manage and eradicating such universe endemic disease using different modalities; such as surgery, radiation therapy, chemotherapy, hormonal therapy and immune therapy; and due to shortage of surgery to eradicate the microscopic residual cancer cells, other modalities have been inevitable for radical treatment. Among these models, conventional radiation therapy has been used in developing countries of Mideast and Africa utilizing 60Co-teletherapy machine and linear accelerator that resulted in good to excellent outcomes in 80% to 95% of cases after breast irradiation to total doses of 45-50.4 Gy in daily fractions of 1.8 to 2.0 Gy  to receive a dose of 95%-107% of the prescribed dose by the planning target volume, which accompanied with some serious consequences due to considerable radiation dose received by adjacent vital organs (sensitive) (eye’s lens, thyroid gland, lungs, and shoulder joint) that may induce lens’s cataract, hypo/hyperthyroidism, lung’s pneumonia/fibrosis, joint stiffness. The appearance of eye’s radiation sickening has been noted within 4-8 years post radiotherapy course relative to total dose as 20% response with a dose of 40 Gy, 50% with a dose of 50 Gy and 100% response with a dose of 57 Gy. Also radiation retinopathy (loss of vision or visual acuity) has been noted within 5 years post radiotherapy; consequently Monroe et al. reported that: after < 50 Gy, there was 4% rate of retinopathy received by at least 25% of the globe with conventional fractionation and modern conformal techniques. Whereas Marks et al. and Mayo et al. stated that: “the whole organ dose of 50 Gy is associated with < 1% risk of blindness and between 55 and 60 Gy, the risk of blindness is approximately 3% to 7%). Regarding the joints response to radiation, a dose up to 6500 cGy in 2 Gy/fraction is tolerable, however the risk is proportional to the volume treated with doses greater than 55 Gy such as radio-osteonecrosis which occur after 1-2 years of radiotherapy course among 2–20% of patients when irradiated with a fractionated radiation doses greater than 60-65 Gy. The thyroid damage presented in forms of hypothyroidism, with low thyroxin and elevated thyroid stimulated hormone (TSH) has been noticed at a fractionated dose of >18 Gy and the high risk occur after 5 years of irradiation or 8 years after fractionated irradiation at doses greater than 35 Gy which is less common. Therefore the trend of this study will focus on the calculation of radiation dose received by these critical organs (eye, thyroid and shoulder joint) in external irradiation of breast cancer due to their presence near to radiation field using Day’s method calculation and TLD, which in turn serves the choices of implementing the best radiation technique and suiting the ethical issues in the field as well as to determine the accuracy of Day’s methods to be applicable and helpful for those countries who use conventional radiation therapy.

With Regards,
Sara Giselle
Associate Managing Editor
Journal of Medical Physics and Applied Sciences