Effect of symptom-to-treatment interval on prognosis in lung cancer

To evaluate the relationship between delayed diagnosis and the degree of invasion and survival in lung cancer.

One hundred and three patients (96 men) with lung cancer were included. Stages in the diagnosis of lung cancer were classified as follows: symptom-to-doctor interval, i.e., the interval from the first symptoms related to the presence of lung cancer to the first consultation with a medical professional; doctor-to-diagnosis interval, i.e., the interval between the first medical visit and confirmation of the diagnosis; and diagnosis-to-treatment interval, i.e., the interval between diagnosis and complete TNM staging and treatment. The symptom-to-treatment interval (STI) was the sum of the 3 intervals. The degree of invasion was determined by the TNM classification.

The patients were followed up for a mean period (= SD) of 7.4+/-8.7 months. Seventy-six (74%) patients were diagnosed with non-small cell lung cancer (NSCLC) and 27 patients (26%) with small cell lung cancer (SCLC). The mean length of STI was 120+/-101 days (median, 90). The mean length of the symptom-to-doctor interval was 63+/-62 days (median, 45), while the doctor-to-diagnosis and diagnosis-to-treatment intervals were 41 +/-82 days (median, 10) and 16+/-12 days (median, 12), respectively. When the STIs of the patients were correlated with tumor stage, tumor invasion, lymph node involvement and metastasis, no significant differences were found. Patients with an STI longer than 60 days had a significantly longer survival. Regarding the type of lung cancer and STI, the median survival was shorter in patients with an STI of less than 60 days both in NSCLC and SCLC, although this was not statistically significant in SCLC.

The shorter the diagnostic interval, the shorter was the median survival in our study. The reason for the apparent discrepancy between poor prognosis of lung cancer patients in spite of early diagnosis might be much faster progression of the disease itself.