Analysis of Late Radiation Proctitis Among Patients Treated for Cervical Cancer: A Comparative Study Between Linear Accelerator and Cobalt Teletherapy

Background

Concerns have been raised over adequate target volume coverage with conventional 2-dimensional planning owing to wide variations in pelvic anatomy between individual patients. To improve tumor volume coverage, increasing numbers of patients are being treated with 3-dimensional conformal radiotherapy (3DCRT), resulting in increased treatment volume as opposed to conventional planning. This study compares the occurrence of late radiation proctitis among patients with carcinoma of the cervix treated with 3DCRT using a linear accelerator (LINAC) versus conventional therapy using a telecobalt unit.

Patients and Methods

A total of 66 patients with carcinoma of the cervix treated with curative intent between August 2006 and August 2012, having a minimum of 6 months of posttreatment follow-up, were reviewed retrospectively. Whole-pelvis irradiation was administered in cobalt teletherapy using the box-field technique (33 patients) or using 3DCRT on a 6-MV LINAC (33 patients), followed by low-dose-rate intracavitary brachytherapy to a dose of 30 Gy.

Results

The median ages of patients treated on cobalt teletherapy and LINAC were 50 and 52 years, respectively, and the median follow-up durations were 24 and 18 months, respectively. Seven patients (21%) developed radiation proctitis in the cobalt teletherapy arm, compared with 12 patients (36%) in the LINAC arm (P = .03; χ² test).

Conclusion

There is a significant increase in the incidence of late radiation proctitis in patients treated with the 3DCRT technique compared with the conventional technique. The effect of associated factors such as rectal dose during brachytherapy needs to be studied before a definitive conclusion can be drawn.