Small cell lung cancer survival: 3 years as a minimum for predicting a favorable outcome

To define the minimum survival time indicating a significantly reduced risk of recurrence of small cell lung cancer (SCLC) basing on the evaluation of survival of patients (pts) with SCLC who underwent anatomic staging and were exposed to combination chemotherapy (CT) (including combined modality treatment).

Eight pts being our 'historic' group submitted to the NCI Registry for Long Term Survivors with SCLC (est. 1977) and a following 657 unselected pts diagnosed, staged, treated and undergoing life-long follow-up at a single institution between the years 1981 and 1996. For those among our pts who had no evidence of metastatic disease, but had not undergone thorough staging, we have arbitrarily created an intermediate group referred to as 'XD'.

Of the 657 pts 111 survived 2 years or more. Among these 111 there were 88 pts with LD at presentation, 11 with 'XD' and 12 with ED. Of the 111 pts surviving 2 years 51 (51/111) were re-treated for relapse before 24 months. From this group of 111 2 year-or-more survivors 45 (41%) died between 2 and 3 years. From year 3 onwards mortality decreased substantially-eight pts died in the 3-4 year interval and eight in the 4-5 interval-accounting for 14% of all the 2 year survivors. We did not observe any failure of the primary tumor beyond a period of 5 years-both in our 'historic' and the analyzed group. After 5 years development of a second primary tumor, mainly lung cancer, is one of the major causes of death in pts 'cured' of their primary tumor.

The shortest survival-time which allows predicting a significantly reduced risk of recurrence of SCLC is 3 years. The same landmark was achieved with the estimation of hazard function and allowed to find a remarkably decreased risk of death at the point of 3 years.