In elderly cancer patients, metabolic and physiological changes lead to a depletion of lean body mass with acute inflammation, increased susceptibility to physical injuries, depression, cognitive deterioration, and negative energy balance. This condition is referred to as cachexia. Given the high prevalence of cancer cachexia in patients over 70 years old, the early diagnosis of malnutrition and sarcopenia [13–16] must rely on accurate and reliable tools to stop the process of tissue degradation that would lead to a worse prognosis [31,32]. Different screening tools allow the identification of wasting syndrome, or a weight loss greater than 5% [33], compared to the usual weight in the previous six months.
The present study evaluated the validity of instruments such as G8 and MNA for the early diagnosis of cancer malnutrition and eventually sarcopenia. We reported results obtained in 533 patients with more than 70 years of age and a diagnosis of cancer. The risk of malnutrition was assessed in all patients regardless of tumor location, and the results showed that patients at higher risk of malnutrition were those with gastrointestinal tract, lung, pancreatic, head, and neck cancers.
Furthermore, we found that the BMI of elderly cancer patients tends to decrease with the disease progress, but the BMI could not be considered an early and accurate diagnostic tool. From our results, in fact, using screening questionnaires included in the CGA (G8, MNA, ADL, IADL, GDS, and SPMSQ) or using biochemical parameters that better reflect the poor nutritional status in the absence of other diseases or acute infections, malnutrition was detected even before BMI falls under 18.5 kg/m2.
It has been suggested that G8 can be used as a tool for early detection of cancer cachexia and proved as a more sensitive tool than MNA. G8 is useful for the assessment of nutritional status because its items comprise two questions about weight history and the third about BMI, which completes the definition of the risk, making it more precise. By using the G8 screening, we detected the risk of malnutrition in 57% of patients with G8 ≤ 14.
The prevalence of sarcopenia increases with age, especially in hospitalized patients. In these patients, a greater tendency to weight loss was detected and that is also correlated to the type and the site of the disease. In our study, weight loss was recorded in all patients with pancreatic cancer, with a concomitant very low value of G8. The site of the tumor, in this case, results in the alteration of glucose metabolism, hormone, and digestive enzyme secretion, depending on whether the tumor interests the endocrine or exocrine region of the pancreas [34]. The ability of the subject to digest, absorb and metabolize food is compromised and then weight loss can be severe. In patients with head and neck cancer [35], instead, weight loss was explained as a side effect of cancer treatment; chemo and radiation therapies, or even surgery, can damage the mouth parts or the first sections of the digestive tract, making it hard chewing, swallowing, compromising the salivary secretion and the digestive enzyme activity. These patients were in fact the majority of those who reported symptoms such as dry mixing bowl, loss of taste and smell, and decreased salivary secretion. The tumor may also cause a physical obstruction to the passage of food and prevent the patient to eat normally.
According to other studies [33,34], we demonstrated that there was a greater tendency to weight loss among patients with gastrointestinal cancer than in patients with other types of cancer. The reduced food intake for these patients has greatly influenced the value of the final score of G8 and MNA, so permitting a very rapid detection of the nutritional impairment even in the absence of biochemical parameters confirmation. So, it was possible to define a higher prevalence of weight loss in patients with gastrointestinal cancers considered among all patients at risk by the score G8 ≤ 14, although in a lower percentage if compared to patients with pancreatic and head and neck cancers.
A more accurate description of the nutritional status of the patient was obtained by checking the results of G8 through the administration of MNA together with ADL, IADL, GDS, and SPMSQ, which have enabled the best description of the geriatric profile and frailty degree.
Cancer cachexia in older patients may develop and progress because of the geriatric syndrome, so it is not enough to only evaluate the score of MNA, but also the other assessment questionnaires are necessary. The patient could have been already at risk of malnutrition even without losing weight or without having a BMI < 18.5 kg/m2 and having a good anthropometric evaluation.
Through the analysis of the results obtained with the MNA administered to patients who presented G8 ≤ 14, the risk of malnutrition was detected in about 50% of all patients, and 73% of them showed a total score of MNA who confirmed the risk of malnutrition, thus requiring a nutritional intervention. Similarly, the first screening by MNA excluded the risk of malnutrition for the 50% of patients presenting G8 at risk, despite both tests consisting of the same questions, except those related to drugs taken, general state of health, and age; this was confirmed by the total score of MNA ≥ 24 for the 92% of them. Therefore, for all patients who presented no nutritional risk based on the values of total MNA, with both MNA screening ≤ 11 and MNA screening ≤ 12, a nutritional intervention was not required. Almost all patients showed a worsening prognosis in terms of weight, appetite, and physical and cognitive status, with the decline of ADL and IADL values, inadequate nutritional intake, and hypoalbuminemia.
Considering these results, even when MNA screening did not describe a state of malnutrition and values of G8 ≤ 14 are associated with movement disabilities and/or cognitive deterioration, we cannot exclude the possibility that patients are affected by early cachexia. The recognition of cancer cachexia in elderly cancer patients was so difficult because the symptoms of poor nutritional status in the early stage have often been hidden from those of geriatric syndrome. Weight loss often could not be detected, because the tumor can influence body weight through ascites and edema, which can affect the value of other anthropometric measurements or the basal metabolic rate of the subject and its metabolic demands. The administration of G8 to elderly patients with cancer, however, constitutes the best form of early screening as demonstrated by the results obtained by the administration of MNA.
This questionnaire in fact does not constitute a reliable tool when used as the only diagnostic method: it allowed the detection of poor nutritional status in only a small percentage of patients, underestimating the presence of risk in 40% of those who not only have obtained a score of G8 ≤ 14 but who also presented hypoalbuminemia and GNRI < 92. In fact, some patients with an MNA ≥ 24 were at risk of malnutrition if evaluated by the G8 score, thus having a worse prognosis.
It is understood, therefore, that the risk of malnutrition could be suspected even when G8 and MNA values are included in the range of normality. It is more appropriate to compare these results to biochemical parameters. In our study, the values of serum albumin detected the risk of malnutrition for half of the patients at risk defined by the G8 score, and these were confirmed by values of GNRI < 92 in all cases. Our results agree with other studies, demonstrating that albumin is a strong prognostic indicator of malnutrition [36–38].
Therefore, it is necessary to integrate diagnostic screening with biochemical analysis, allowing the detection of risk even in patients with normal scores of G8 and MNA. For the definition of neoplastic cachexia, the association between hypoalbuminemia and weight loss constitutes the best and more sensitive tool in subjects who do not present other types of pathologies. The limit of these parameters is that they can be altered when a patient is suffering from acute infections, kidney or liver diseases, and conditions that can affect serum protein concentration. Moreover, the error given to the long half-life of the protein needs to be considered too. Thus, albumin concentrations could be in the normal range even in patients who begin to manifest protein reserve depletion, which characterizes the wasting syndrome. More than half of patients with albumin concentration ≥ 3.5 g/dl showed a total score of G8 ≤ 14 and a score ≤ 11 on the first screening of MNA and almost half of them reported a moderate or severe weight loss and an inadequate daily protein intake. This shows that even serum albumin could not be considered an accurate diagnostic tool for cachexia unless in association with the test scores, especially when malnutrition is diagnosed in its early stages.
However, patients who reported the lowest values of serum albumin were mainly suffering from gastrointestinal tumors demonstrating a major risk of malnutrition with respect to patients affected by other types of tumors. This aspect was also demonstrated by the GNRI score, which showed the greatest nutritional risk more than all the other instruments used [39,40]. The accuracy of GNRI allowed early detection in patients where other tests did not detect the problem. Therefore, this parameter has been used both as a reference point for the confirmation of a nutritional risk already highlighted by the screening test and as a criterion for further investigation when they have proven unsatisfactory. In our study, the association of GNRI with G8, MNA, and CGA allowed the quantification of the health risk in 95% of malnourished patients, which includes a higher percentage of gastrointestinal, pancreatic, head and neck, and lung cancer patients.