Breast cancer is characterized by the uncontrolled development of cancer cells in the mammary gland. It is a major public health problem because of its high incidence and mortality. With 2.088.849 new cases identified (11.6%) and 626.679 (6.6%) cases of death worldwide, it accounts for 25.1% of all cancers   .
The incidence of breast cancer is 4 to 10 times higher in Western countries (mainly in the United States and Northern Europe) compared to Asia and Africa   .
In sub-Saharan Africa, the incidence of breast cancer varies by country  ; in Mali, from 2006 to 2010 it is in second place after the cervix, with a relative frequency of 18.7%, it is the second cause of cancer death after cervical cancer  . It is currently first cancer in terms of incidence according to the 2010-2017 Bamako cancer registry.
To our knowledge, in Mali, there are no published data on the epidemiological and clinical characteristics of this cancer. This is why, in this work, we propose to study the epidemiological and clinical characteristics of breast cancer treated at the radiotherapy center of the Mali Hospital of Bamako.
2. Patients and Methods
This was a retrospective and descriptive study of the data of patients monitored for breast cancer at the Bamako Radiotherapy Center of the Mali Hospital, between April 2014 to December 2016.
Included in the study was any case of histologically proven breast cancer and seen at the radiotherapy center for management, regardless of age and gender. Patients with no histological diagnosis were not included in this study.
The data was collected from the patient’s medical records and the radiotherapy department’s registry.
The parameters studied were: age, sex, family history of breast cancer, menopausal status, parity, breast tumor location, histological type, histological grade, stage of classification of the breast. Cancer.
The classification of cancers was based on the clinical examination according to the location of the primitive and on the extension assessment.
The clinical examination specified if possible the size of the tumor as well as its extensions. The radiological examinations were most often a mammography coupled with an ultrasound, a chest x-ray, an abdominopelvic ultrasound and/or a thoraco-abdominopelvic CT scan. Bone scans were not requested because they were not feasible in Mali. The search for hormonal receptors and the Her 2 neu membrane receptor by immunohistochemistry was also not feasible in Mali during the study period. The seventh edition of the TNM classification of the International Union against Cancer (UICC) was used for staging  . Data analysis was done using SPSS23.0 software.
From April 2014 to December 2016, we received 890 cases of cancer including 134 cases of breast cancer, a frequency of 15%. With only one man the sex ratio (H/F) was 0.007. The mean age of our patients was 47 ± 11 years with extremes ranging from 18 to 88 years. The most represented age groups were 33 - 47 years old with 45.5% and 48 - 62 years old with 38.8% (Table 1).
In the cohort, 3% of patients had a family history of breast cancer. They were pauciparous in 59%, multiparous in 32% of cases and nulliparous in 8% of cases. At the time of diagnosis, 50% of the patients were menopausal.
The clinical sign of discovery was a mammary nodule in 98% of patients. Mastodynia was found in 65% of patients. In 67%, lymph node involvement was the mode of revelation. Nipple discharge was present in 18%, the appearance of orange peel was found in 4% and ulceration in 16% (Table 2).
Ultrasound was performed in all patients. It was coupled with mammography in 94% of cases.
Table 1. Characteristics of the study population.
Table 2. Characteristics of the study population.
Histologically, infiltrating ductal carcinoma was found in 94% of patients. It was followed by infiltrating lobular carcinomas (3.7%) and metaplastic carcinomas with 1.7%. Sarcomas were found in 0.7% of cases. The rank of Scarff Bloom and Richardson (SBR), could be evaluated in 65% of which 4% of Grade I, 37% of Grade II and 23% of Grade III.
As part of the extension assessment, 76% of patients had chest X-rays and 99% had abdominal ultrasonography. Thoracoabdominopelvic CT was performed in 60% of patients (Table 3).
Table 3. Characteristics of the study population.
Mean tumor size was 87 ± 43 mm with extremes ranging from 6 to 182 mm. Patients were graded and staged according to the criteria of the seventh edition of the TNM classification of the International Union against Cancer (UICC). Thirty-one (31%) of the patients had a tumor size greater than 5 cm. In 47% of cases, the tumor was extended to the chest wall and/or the skin. The ipsilateral axillary lymphadenopathies were found in 38% of patients, while 18% had fixed homolateral axillary adenopathies and 12% had supraclavicular lymphadenopathies. Three percent of the patients had secondary locations. Stage III was predominantly represented with 72%, followed by stage II with 24% and stages I and IV with 2% each (Table 3).
Breast cancer is the first cancer in the world   . In 33 months, at the Radiotherapy Center of the Mali Hospital, we collected 134 cases out of 890 cases of cancer (15%), an average of 30.25 cases per year. In Africa the incidence of breast cancer varies between countries. So in Niger, Zaki et al. report 64.5 cases per year  , in Togo, Darré et al., Report 22.5 cases per year  . Overall this frequency found in Africa is lower than in Europe and represents 24.2%  .
In our study, women accounted for 99.2% of cases, a sex ratio (M/F) of 0.007. This result is lower than those reported in Niger and Togo which were respectively 0.03 and 0.023   . This could be explained by the fact that our study was monocentric. For some authors, the rarity of breast tumors in the male sex is explained by the atrophic nature of the gland, the delicacy of the milk ducts, the absence of acini and the abundance of fibrous tissue in man  .
As for age, the extremes ranges from 18 and 88 years old, with an average age of 47 ± 11 years. These results are comparable to those found in Cameroon  . In our series, breast cancer was common in both patients before and after 50 years. The most represented age groups were respectively 33 - 47 years old with 45.5% and 48 - 62 years old with 39% while in the Cameroonian series 17% of the patients were between 45 - 49 years old  . In Niger, Zaki et al. found 69.89% of breast cancers in women before age 50  . The results found in Africa are different from those found in the USA or 50% of cases of breast cancer are diagnosed in women over 65 years. In Europe, the incidence of breast cancer is 210 per 100,000 for women aged 50 - 54 and more than 300 per 100,000 women at age 70   .
In our family history study, so-called hereditary breast cancer is rare with a frequency of 3%. This result is significantly lower than the Cameroonian and Tunisian studies, which had recovered respectively 23% and 13.23%  .
Conventionally, multiparity is a factor in reducing the risk of breast cancer, in our series, 32% of patients were multiparous. This result is lower than that of Sano et al. (7) with 54% multiparas among women with breast cancer in Burkina Faso  . Breast cancer was diagnosed in 48.5% of premenopausal patients, which is lower than the study by Dem et al. Who found that 57.3% of these malignancies are diagnosed before age 50  .
The tumoral involvement concerned the left breast in 60% of cases, comparable to the Guinean series which found a frequency of 56%  . In 1.5% of cases the involvement was bilateral, in the literature the bilateral involvement varies between 3% - 13%  . Regarding the circumstances of discovery, the self-examination of nodules was found in 98% of patients, which may or may not be associated with mammalian mastodynia and axillary adenopathy in more than 60% of cases, whereas in the Tunisian series, the nodule was present. at 81.4%  .
Histologically, there was a preponderance of infiltrating ductal carcinomas with 94%, followed by infiltrating lobular carcinoma with 3.7% and metaplastic carcinoma with 1.7%. These results are comparable to the Moroccan and Cameroonian series but with different proportions   .
There was a predominance of SBR grade II in our patients, which corroborates with the Cameroonian study which also found a higher frequency of grade II SBR (66%), followed by Grades III and I with 20% and 14%  . However it should be noted that 35% of our patients had not been able to benefit from this grading. Immunohistochemistry was not practiced during the study period; no patient was able to benefit from a search for hormonal receptors and Her2neu.
In our series, the average tumor size was 87 mm, much higher than the patients of the Moroccan series which was 36 mm, this could be explained by a lack of awareness and screening on breast cancer in Mali.
Stages II and III were predominantly represented with 24% and 72%, thus requiring much more radical treatments. Bouchbika Z et al.; had demonstrated the value of early diagnosis and mammography screening, which increased from 2004-2009 to Ibn Rochd Hospital in Casablanca, stages II and III from 50% and 30% to 54% and 16%; which makes it possible to increase the rate of conservative treatments  .
Our results concern the only cancer treatment center by radiotherapy in Mali, but are comparable to those of the Bamako cancer registry.
In our context breast cancer remains a major public health problem; in our series, we find a slight predominance of subjects under 50 years. The diagnosis is usually late in our context, hence it is the importance of raising awareness and screening before the age of 50. This will promote more conservative and targeted treatments that will improve patient survival.
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