Estimating cancer survival in developing countries. Use of reply-paid post cards to augment follow-up information

Survival from cancer is one of the indices to evaluate cancer control activities. Reliability of survival estimates depends to a large extent on the completeness of follow-up information available for patients in the study group. Loss to follow-up (LFU) is one of the potential problems introduced in follow-up of cancer patients. An attempt is made to improve the follow-up system for reducing the LFU of cancer patients by repeatedly sending reply-paid post cards for the LFU patients. A total of 353 ovarian cancer patients registered at the Regional Cancer Centre, Trivandrum during a three year period and followed-up to a total of five years showed 67 percent loss to follow-up. The five-year survival rate of this group calculated using Kaplan-Meier method under the assumption that the LFU's occurred at random was 75 percent. Efforts to improve the follow-up rate for the study population were made through the simple and cost effective method of postal enquiry which resulted in a reduction of 63 percent of losses to follow-up. Incorporation of this information in the data brought about a revised five-year survival estimate of 55 percent. The reply paid post card system was found to be effective in obtaining useful follow-up data. The result shows that LFU can be reduced by better design of survival study.