The present study shows significant differences of the body and functional status prior to chemotherapy for patients with advanced GI cancer compared to breast cancer patients and healthy women. Gait speed, phase angle and force are below the cut-off values for worse prognosis of survival and may reflect a diminished tolerance of chemotherapy. To the best of our knowledge, this is the first report that evaluates the status of advanced GI cancer patients prior to treatment.
The Short physical performance battery
The results of the SPPB reflect the impaired functional capacity. This impairment result in a decreased activity of daily living (ADL), reduced quality of life and a higher risk of mortality has to be assumed . Functional status is a more reasonable indicator of cancer treatment tolerance, therefore the obtained results reflect a possible reason for the known variety of side effects in advanced GI cancer patients.
The mean phase angle of advanced GI cancer patients was 4.5° ± 0.75. According to Hui et al.  the survival time correlated with the phase angle in advanced cancer patients. In the study of Hui et al.  the mean survival with a phase angle of 4.0-4.9 were 112 days. Low phase angle values are strongly predictive of low muscle strength, impaired quality of life, symptom severity and impaired ADL and survival time [18–20]. Another study reports an increased toxicity with reduced lean body mass . In his study, Ali defined a dose-limiting toxicity. Oxaliplatin doses less than 3.1 mg/kg lean body mass were associated with low risk of dose-limiting toxicity. There was negligible toxicity in the patients below the cut point. Chemotherapy-induced toxicity in patients treated with paclitaxel and cisplatin was associated with malnutrition and hypoalbuminemia . Malnutrition of colorectal cancer patients measured with poor scores for MNA was independently associated with increased hazard ratios for mortality and poor MNA-scores were predictive for a less than planned number of chemotherapy cycles in palliative treated patients. The physical aspects showed a clear decline after at least four cycles of chemotherapy .
Gait speed and strength
Skeletal muscle is the largest organ in the human body, constituting 40–50% of total body mass in healthy nonobese humans . Skeletal muscle function is classically defined as the ability to perform muscular contractions, generating external mechanical force, which enables physical activities of daily living and exercise. In addition, skeletal muscle plays a vital role in primary and secondary disease prevention as an essential regulator of metabolic and inflammatory homeostasis . For example, Burden et al.  found that 54% of newly diagnosed early-stage colorectal patients had a handgrip strength, which was below 85% of the age-matched reference range. In accordance, patients with locally advanced prostate cancer undergoing androgen deprivation therapy (ADT) had 29% lower handgrip strength compared with healthy controls . Furthermore, breast cancer survivors evaluated after completion of primary therapy displayed consistently lower muscle strength (20–30%) in seven different upper body exercises compared with healthy individuals . Finally, evidence of late effects on muscle strength has been shown in adult survivors of childhood cancers. For example Ness et al.  found that 18% survivors of extracranial solid tumors, assessed a median of 25 years after diagnosis, displayed muscle weakness, defined as the dorsiflexion torque within the lowest 10th percentile compared with healthy age-matched reference subjects. Muscle loss is the key role of the development of frailty, ADL, disability and impaired quality of life in cancer patients . Also, reduced ankle power generation has been proposed as a major mechanism for reduced walking speed  . Judge et al  reported that walking ankle joint power generation was the strongest predictor of short step length. The reason for the reduced ankle power generation could be plantarflexor muscle weakness. It has been shown that ankle power generation developed during the push-off phase is associated with ankle plantarflexor strength . Usual gait speed at 3.6 km/h respectively 1 m/s will be considered a high risk of functional declines, adverse health outcomes, hospitalization and mortalitiy . The strength of the knee extensors and the usual gait speed of advanced GI cancer patients in the present study were significant reduced compaired to advanced breast cancer patients and healthy volunteers with the same age. In the knowledge that while cancer treatment the strength and muscle function decrease the findings of the present study, another decrease has to prohibit or counteract with resistance training, other physical activities or anabolic steroide.
The daily physical activity of the healthy control with averaged 8774 steps per day reflect a norm collective. In Baumann et al.  same aged healthy women show similar results, a little bit below the recommendations of 10.000 steps per day of the World health organisation. The averaged 3407 steps per day of advanced GI cancer patients could be the result of the decreased body and functional status. This result is beyond other study results of cancer patients with different entities. The consequence of diminished physical activity are long periods of sedentary time. Sedentary time were strongly associated with higher triglycerides and markers of insulin resistance . There is evidence that cancers at different sites (particularly breast, colon, pancreas and prostate) are associated with mechanisms that include hyperinsulinemia, peripheral resistance to insulin and increased production of insulin-like growth factor-1 [37, 38].
The decreased steps of advanced breast cancer patients are not the consequences of an impaired functional or body status. Therefore, possibly the mental situation resulting from cancer diagnosis are the reason of this diminished activity.
Accurate survival prediction is essential for decision-making in cancer therapies and care planning. Also, the probability of many side effects and thereby a decreased quality of life influence the strategy of the therapy. Many studies with physical activity interventions showed positive effects of the body composition, muscle, quality of life, and functional status. Therefore, possibly with some exercise before or while cancer therapy, the therapy tolerance can enhanced, the side effects diminished and indeed the prognosis of survival improved[39–43].