Summary. Cancer rehabilitation programs mainly involve endurance training while little attention has been paid to strength training. Breast cancer (BC) patients lose muscle strength while undergoing adjuvant treatment, thus affecting daily activities and quality of life. Maximal strength training, with an emphasis on velocity in the concentric phase, improves maximal strength and muscle force development characteristics. However, the effect of maximal strength training on quality of life for BC patients undergoing treatment remains elusive. Consequently, the aim of this study was to evaluate the effectiveness of maximal strength training in Health related quality of life in women with newly diagnosed BC. Materials and Methods: 55 BC patients with disease stage I–III were randomized into a training group and control group. The training group performed maximal strength training twice a week for 3 months, whereas the control group followed prescribed treatment without strength training. Overall quality of life was measured by The European Organization for Research and Treatment of Cancer Core Quality of life Questionnaire-C30 and additional BC module BR23 before and after the intervention. Results: The results obtained from pre-tests and those obtained after 3 months of intervention revealed that patients in the training group significantly increased one repetition maximum, by 20.4 kg (20%) (p = 0.001, d = 0.9). Simultaneously, statistically significant alterations were observed in this variable for the control group, one repetition maximum decreased by 8.9 kg (9%) (p = 0.001, d = 0.5). The overall quality of life improved significantly by 13% for the training group with large effect (p = 0.002, d = 0.6), but no relevant changes were observed in the control group (p = 0.44, d = 0.2). Results revealed remarkable changes in overall quality of life after 3-month post-test period between the two groups with large effect (p = 0.002, d = 0.9). The training sessions had helped in diminishing the sense of fatigue by 24% (p = 0.03, d = 0.6), while it had got worse by 25% (p = 0.02, d = 0.4) for the control group. Again, the data on large effect were noticed to differ between the groups (p = 0.01, d = 0.6). Conclusion: Maximal strength training for BC patients was well tolerated, safe and feasible and showed strength improvements that led to improved muscle strength and improved overall quality of life. These data certainly support the therapeutic role for maximal strength training in the treatment of BC.

Background and Purpose Adjuvant breast cancer therapy may reduce maximal muscle strength, muscle mass, and functional performance. Although maximal strength training (MST) has the potential to counteract this debilitating outcome and is shown to be superior to low- and moderate-intensity strength training, it is unknown if it can elicit effective adaptations in patients suffering treatment-induced adverse side effects. Methods Fifty-five newly diagnosed stage I to III breast cancer patients (49 ± 7 yr) scheduled for adjuvant therapy were randomized to MST or a control group. The MST group performed 4 × 4 repetitions of dynamic leg press at approximately 90% of one-repetition maximum (1RM) twice a week for 12 wk. Results In the MST group, improvements in 1RM (20% ± 8%; P < 0.001) were accompanied by improved walking economy (9% ± 8%) and increased time to exhaustion during incremental walking (9% ± 8%; both P < 0.01). Moreover, the MST group increased 6-min walking distance (6MWD; 10% ± 7%), and chair rising (30% ± 20%) and stair climbing performance (12% ± 7%; all P < 0.001). All MST-induced improvements were different from the control group (P < 0.01) which reduced their 1RM (9% ± 5%), walking economy (4% ± 4%), time to exhaustion (10% ± 8%), 6MWD (5% ± 5%), chair rising performance (12% ± 12%), and stair climbing performance (6% ± 8%; all P < 0.01). Finally, although MST maintained estimated quadriceps femoris muscle mass, a decrease was observed in the control group (7% ± 10%; P < 0.001). The change in 1RM correlated with the change in walking economy (r = 0.754), time to exhaustion (r = 0.793), 6MWD (r = 0.807), chair rising performance (r = 0.808), and stair climbing performance (r = 0.754; all P < 0.001). Conclusions Lower-extremity MST effectively increases lower-extremity maximal muscle strength in breast cancer patients undergoing adjuvant therapy and results in improved work economy, functional performance, and maintenance of muscle mass. These results advocate that MST should be considered in breast cancer treatment.

# Corresponding author Communicated by Vija KluðaBreast cancer is a heterogenous disease. It consists of several histological subtypes that can be separated by morphology and immunohistochemistry. The aim of our study was to determine the distribution of breast cancer histological and molecular subtypes, and their relationship with clinical and pathological characteristics. A total of 561 patients who underwent breast carcinoma surgical treatment from January 2003 till December 2012 were enrolled in the study. In total, invasive ductal carcinomas not otherwise specified (IDC-NOS) plus invasive ductal carcinomas no special type (IDC-NST) were observed in 430 patients (76.65% of cases), medullar carcinoma in 14 patients (2.45%), other rare ductal carcinoma subtypes in 13 patients (2.31%), lobular carcinoma in 81 patients (14.4%) and tubulolobular carcinoma in 23 patients (4.19%). Ductal carcinoma, lobular and tubulolobular carcinoma had predominantly luminal A and B subtype, whereas medullar carcinoma had HER2-positive and triple-negative (TN) subtype. Tubular, cribriform, mucinous, papillary, and apocrine carcinomas had predominantly luminal A subtype. Significant differences between breast cancer histological subtypes and clinicopathological characteristics were observed. Our study for the first time reported the distribution and characteristics of breast cancer histological subtypes in Latvian women and relationship to clinical and tumour histopathological characteristics.