Undernutrition is a common problem in patients with cancer, frequency varies according to location of tumor, the stage of the disease and the type of treatment.1 Awareness concerning nutritional status of patients with lung cancer is scarce, however it is estimated that 46% of these patients are undernourished.1 Weight loss affects the response to treatment and the susceptibility to adverse effects leading to a worse prognosis and Quality of Life (QoL).2–4 Undernutrition can progress to cachexia, which encompasses a large spectrum of situations ranging from weight loss to a state associated with a severe disability that generally leads to death.2,5

The QoL is an important outcome of the disease and its treatment and represents a growing concern in controlling the disease. The QoL is described as a prognostic factor in survival of patients with Non Small Cell Lung Cancer (NSCLC).6,7 However, the extent of these conditions in patients with NSCLC is still to be evaluated. The aim of the present study was to assess the association between QoL and undernutrition in NSCLC patients.

A cross-sectional study was conducted among outpatients of Pulmonary Oncology Department of Centro Hospitalar de Vila Nova de Gaia/Espinho, Portugal. Inclusion criteria were being Caucasian, over eighteen years old, with a histological diagnosis of NSCLC. Previous nutritional advice and the inability to complete the self-administration questionnaires were exclusion criteria. Patients were consecutively included in the study sample from October 2007 to May 2008.

The study protocol was approved by the Hospital Ethical Committee and the Administration Board of the study institution. All patients gave their informed consent to participate according with the recommended in the Declaration of Helsinki .8

This sample includes 56 patients diagnosed with NSCLC (14 female and 42 male) with an overall mean age 64.3 years (standard deviation=10.8 years). The group 1 is composed of 14 patients and group 2 of 42 patients.

Female patients are older than male patients and most patients have a low education level. The most frequent histological type is the adenocarcinoma and the majority of patients had no family history of cancer. The most common previous treatment in patients of group 1 was surgery/ surgery with adjuvant therapy, while in patients of group 2 was chemotherapy. Most patients of group 1 (78.6%) were not receiving any treatment at the time of the evaluation. However, 15 patients of group 2 were undergoing chemotherapy (Table 1).

The proportion of weight loss from the time of the first symptoms until the time of data collection varied. Eight patients (57.1%) of group 1 increased their weight, while 22 patients (52.4%) of group 2 lost weight. Sixty-four percent of patients of group 1 presented a total numerical score of PG-SGA between 4 and 8, while 57.1% of group 2 patients presented a total numerical score ≥ 9. Although 35.7% of patients of group 2 were moderately undernourished or at risk of undernutrition and 9.5% of patients were severely undernourished, only one patient (7.1%) of group 1 was moderately undernourished or at risk for undernutrition (Table 1).

When QoL was stratified according to nutritional status, undernourished patients had a lower global health status/QoL (p=0.003) and worse functioning (physical, role, emotional and social). They also more frequently showed fatigue (p<0.001), nausea and vomiting (p<0.001), pain (p=0.006), appetite loss (p<0.001) and constipation (p<0.001) (Table 2).

Analysing QoL from the QLQ-C30 stratified according to the stage of disease, we can observe that the differences do not reach statistical significance. However, the more advanced stages of disease are associated with a worse QoL, according to the global health status/QoL and functional scales. When symptoms were analysed, patients in group 2 had a lower proportion of symptoms like insomnia or similar proportion of symptoms (nausea and vomiting, pain, lack of appetite, constipation, diarrhoea and financial difficulties) when compared to patients in group 1.

Analysing QoL evaluated by QLQ-LC13, after stratification by nutritional status, we can observe that undernourished patients presented dysphagia more often (p=0.025) (Table 3). No significant differences in any of the items considered were found when data was analysed according to stage of disease.

A significant association between undernutrition and the global health status/Qol was found for functional scales (except for emotional functioning), symptom scales/ items with the exception of dyspnoea, insomnia, diarrhoea and financial difficulties. Lack of appetite showed a high correlation with undernutrition (rho=0.7) and moderate correlations have been found between undernutrition and fatigue, nausea and vomiting and constipation (Table 4).

Regarding the association between QoL (evaluated by QLQ LC-13) and undernutrition only a weak association with statistical significance between dyspnoea and dysphagia and the PG – SGA was found (Table 4).

Patients with NSCLC have a high frequency of undernutrition in advanced stages of disease and undernutrition is associated with worse QoL. Twenty patients (35.7%) were at risk of undernutrition or undernourished.

No differences were found for QoL by stage disease. However, analysing QoL stratified according to nutritional status differences in various parameters were identified. As expected, undernourished patients have a worse global health status/QoL, as well as worse physical role, emotional and social functioning and more symptoms than patients without undernutrition. A high correlation with the lack of appetite, and a moderate correlation with fatigue, nausea and vomiting, constipation and undernutrition were found.

These results are in line with those which have shown a worse QoL in undernourished patients with various cancer diagnosis. Ovesen et al.19, in a study with 104 patients with small cell lung cancer, breast cancer or ovarian cancer, observed that patients with a moderate weight loss had more psychological stress and worse QoL. Andreyev et al.20 observed in 1555 patients with esophageal, gastric, pancreatic or colo-rectal cancer that weight loss had a significant impairment in QoL. Ravasco et al.21, in 271 patients with head, neck, esophageal, gastric or colo-rectal carcinoma, reported that weight loss and reduced energy and protein intake were associated with a worse QoL. Gupta et al.22 in a study with 58 patients diagnosed with colorectal cancer, showed that patients without undernutrition had better QoL. Nourissat et al.23, in 907 patients with colo-rectal, stomach, liver, oesophageal, ovarian, pancreatic, lung, prostate, breast, cervical or bladder cancer, identified an association between weight loss and worse QoL.

This study has several strengths. Patients included are only from one center, allowing a more homogeneous sample. Since different types of cancer and different histological types have different behaviors, we restricted the sample to a single sub histological type of lung cancer (NSCLC) in order to increase homogeneity.

To characterize the nutritional status, we used a validated instrument in order to achieve a more correct and detailed description. PG-SGA is the reference method used to assess nutritional status in cancer and it is recognized by the Oncology Nutrition Dietetic Group of the American Dietetic Association as the reference method of nutritional assessment for cancer patients.10 This choice is a step forward compared to previous studies evaluating nutritional status in cancer patients, which defined undernutrition only by weight loss .19–21,23

All data was collected by the same researcher limiting the possibility of inter-observer variation. Demographic characteristics such as age and gender are comparable to characteristics previously found in a study realized by the Working Committee of Lung Cancer of the Portuguese Society of Pneumology.24

The transversal design of this study is a weakness, limiting the study of a causal relation. Also, the reduced sample size does not allow a multivariate analysis approach to evaluate the association of undernutrition with QoL independently of other factors related to these conditions, such as the stage of disease, side effects of ongoing treatment and outcome of treatment. The low number of observations in some strata could have increased the possibility of type II errors, due to the lack of statistical power. A high proportion of the sample was not evaluated immediately after the diagnosis, and, at the time or evaluation, had had or were having under various therapeutic options which could have led to higher frequencies of undernutrition. This is a heterogeneous sample including patients at very different stages of the evolution of the disease. However, this sample is typical of the patients being treated in a health care unit of this kind.

In summary, patients with NSCLC have a high frequency of undernutrition in advanced stages of disease (early stages of disease: 1.8% vs. advanced stages of disease: 33.9%). Undernourished patients present a worse global health status/QoL, physical, role, emotional and social functioning. They also present more symptoms, including fatigue, nausea and vomiting, pain, insomnia, appetite loss and dysphagia. Undernutrition is associated with worse QoL, specifically: appetite loss, fatigue, nausea and vomiting and constipation. These results present a first approach to this issue which highlights the importance of nutritional status and QoL of NSCLC patients, since these parameters can be often modified when detected early and properly evaluated.

The authors declare they have no conflicts of interest.