Background reast cancer is the second most frequently diagnosed malignancy, it is also the leading cause of cancer death in women. cancer patients early-stage breast cancer undergo primary breast and lymph node surgery regions, with or without radiotherapy. Afterwards, adjuvant systemic therapy may be indicated. However, some patients with earlystage invasive breast cancer may be treated with neoadjuvant therapy first. Chemotherapy is associated with effects side effects, including nausea, vomiting, diarrhea, hair loss, fatigue, mucositis, cytopenia, ovarian failure, cardiac toxicity, and emotional and psychiatric. Among the known side effects of chemotherapy, the weight change and its association with a poor prognosis of the disease (1)(2)(3) Weight change in breast cancer patients can influence the quality of life, self-esteem and development of new comorbidities. Studies report greater risk of disease recurrence and worse prognosis when performing the treatment (1)(2)(3)(4)(5)(6). One meta-analysis showed that a weight gain of 10% or more after the diagnosis of Breast cancer is associated with a higher mortality rate (4). On the other hand, there are recent studies showing no significant changes in the weight of patients with breast cancer undergoing chemotherapy (3,5,6). Based on these data, studies have also demonstrated the importance of nutritional monitoring and exercise during the chemotherapy treatment (7)(8)(9).

A meta-analysis showed that weight gain during chemotherapy was greater in articles published up to the 2000s and that there is a trend of weight gain be decreasing over the years (1). In line with this idea, a meta-analysis Canadian added that weight gain is more associated with chemotherapy adjuvant, with long-term treatments and increased in pre menopause (10). In this context, the literature suggests that the duration of chemotherapy can also be a factor for weight gain (11,12) and also shows that pre-menopausal patients show greater weight gain than post-menopausal patients (6,13). The association between weight gain and chemotherapy treatment has shown general trend of decreasing magnitude in recent years. It is known that changes in weight change may be unfavorable in body composition. the consequence disease-free survival and self-esteem, associated with the emergence of psychiatric disorders in patients with breast cancer after chemotherapy evidences the importance of research on the subject. Therefore, this study aims to evaluate changes in weight and BMI (Body Mass Index) in breast cancer patients non-metastatic patients undergoing adjuvant and/or neoadjuvant chemotherapy in a of oncology in southern Brazil.

To V.

Outcome 122 female patients with non-metastatic breast cancer and mean age 53.48 ± 12.23 years were followed up for one year. 44.3% of patients were postmenopausal. Regarding the comorbidities presented, the following stand out: Systemic Arterial Hypertension (34.4%), Hypothyroidism (10.7%), Dyslipidemia (6.6%), Diabetes (3.8%), Deep Vein Thrombosis (2.5%), Rheumatologic Disorders (3.3%), Cardiac (2.5%). 1.6% of the patients maintained their alcohol consumption and 12.3% maintained the smoking during treatment. In the studied sample, 3.3% had generalized anxiety, 12.3% depression, and other psychiatric disorders in follow-up were found in 4.1% of patients. During this period, 7.4% of the patients developed COVID 19. Table 1 shows the characteristics of patients.

Regarding the type of breast cancer, 90.2% of the patients have breast cancer invasive ductal carcinoma, while 3.3 had invasive lobular carcinoma and 3.3% the others types. 70.5% of the patients had the positive hormone receptor subtype and 35.2% Her-2 positive. The stages of breast cancer were also analyzed, with the majority being of stage IIB patients (35.2%). Table 2 shows the characteristics of cancers of breast.

As shown in table 3, in the analyzed sample, 51.6% performed neoadjuvant chemotherapy, 36.1% adjuvant chemotherapy and 12.3 underwent both types of chemotherapy. The chemotherapy time was less than or equal to 1 year for 77% of patients. In the annual follow-up, 9% had adverse reactions to chemotherapy, the majority being a mild reaction. It is known that the treatment of breast cancer it is multifactorial. In relation to other treatments associated with chemotherapy, 45.9% of patients underwent hormone therapy and 50% of patients underwent radiotherapy.

Patients were classified according to the BMI classification of the World Health Organization (WHO) before and after chemotherapy. You results are described in table 4. Most of the sample was pre chemotherapy with weight at the first visit before chemotherapy with a mean of 75.4 ±16.95kg; Weight at the last post-chemotherapy visit with a mean of 75.61 ±17.29 kg; Height had a mean of 160.39 ± 7.20. The BMI at the first consultation before the chemotherapy presented an average of 29.25±5.94; BMI at the last consultation showed an average of 29.32 ± 6.01. When statistically comparing by Student's T Test the weights and BMI before and after chemotherapy showed P=0.711 and P=0.774 respectively. A non-significant relationship was observed between the patients' baseline weight and postpartum weight. chemotherapy.

Regarding the BMI classification according to WHO, there was no significant change in the status between pre and post chemotherapy P=0.607. 67.3% remained in the eutrophic category. 54.5% remained in the obesity category I. 83.3% remained in the obesity category II. 57.1% remained in the obesity category III. 59.6% remained overweight. Variations in ranking during follow-up are represented in table 5.

We evaluated pre-and post-chemotherapy weight changes among women with non-metastatic breast cancer. Most of the studied sample presented time of chemotherapy less than or equal to one year. The medical literature suggests that the duration of chemotherapy can be a factor for weight change, and long-term treatments duration have greater weight gain. (10). Furthermore, unlike the presented in our study, young and pre-menopausal women would have greater weight gain according to some previous research (10,11,14,15) Consistent with our results, a narrative review suggested that women with normal BMI at baseline were more likely to gain weight compared with overweight women (10). We demonstrated that eutrophic women had more chance of gaining weight than overweight patients after chemotherapy. 32.1% of patients in the eutrophic classification were overweight after chemotherapy and 22.7% of patients with Grade I Obesity had Grade II Obesity after chemotherapy, while 5.6% of patients with grade II obesity had Grade III obesity.

In the same context, other articles also demonstrated no significant weight change among patients with non-metastatic breast cancer before and after chemotherapy (3,6). Article in Saudi Arabia followed 228 women between 18-80 years of age with non-metastatic breast cancer and early-stage chemotherapy and did not obtain significant changes in weight (3). Likewise, a Korean survey evaluated 260 women with non-metastatic breast cancer and showed no change in significant weight (5). Furthermore, although weight gain still prevails as an effect postchemotherapy collateral, studies have shown a tendency for a decrease in weight change in women with breast cancer after chemotherapy over the years (1).

Some factors may have contributed to the nonweight gain of patients in our study: regular follow-up with a nutrition team, the time of chemotherapy and the type of chemotherapy performed. Studies show that the increase of taxanes in treatments has suggested less weight gain in more recent years (1). The group of patients in follow-up was also considered to have less previous comorbidities in relation to the reference studies, being another possible fator not to change weight. 51.6% of patients underwent neoadjuvant chemotherapy, it is known that studies on the association of neoadjuvant chemotherapy and changes in weight are still limited in the medical literature.

This study did not reveal significant weight changes after one year of adjuvant and/or neoadjuvant chemotherapy. Furthermore, most patients with breast cancer followed-up during the period did not change their BMI classification according to WHO. Since studies show a trend towards a reduction in Weight changes over the next few years in breast cancer patients are needed new studies, considering the different regional features.