The changing costs of radiation treatment for early prostate cancer in Ontario: a comparison between conventional and conformal external beam radiotherapy.

PURPOSE

Prostate cancer represents a large part of the workload for radiation oncology departments in Canada. Recent evidence suggests that conformal external beam radiotherapy improves results. The planning and treatment process for conformal patients requires a greater amount of resources that are in short supply in Ontario. An understanding of these differences is important to provide an accurate estimate of future radiation needs of the province. These differences can be quantified in a cost model that portrays the direct costs of delivering external beam radiotherapy in Ontario. With a developed cost model, a prospective direct cost comparison between standard four field external beam radiotherapy versus conformal radiotherapy in early stage prostate carcinoma was designed.

METHODS

Activity based costing has been used to create a model of radiotherapy related costs for prostate cancer. A process map was developed which separated the process in five activities for conventional radiotherapy and six activities for dose escalated conformal radiotherapy. Time was recognized as the important cost driver within each activity. The time required for pre-treatment preparation (CT planning, dosimetry, simulation, and other preparatory work) and actual treatment times were collected prospectively. Treatment times were collected in 414 patients. The annual costs of capital equipment purchase costs and specialized construction of hospital space for radiotherapy equipment were amortized using a 6% discount rate plus the cost of annual maintenance. Indirect costs were not included in this cost analysis.

RESULTS

An activity based costing model using time as the primary cost driver reflects the additional costs of conformal over conventional external beam radiotherapy. The costs of single phase and double phase six field conformal therapy with 42 fractions delivered was 7867 Canadian dollars and 8227 Canadian dollars per patient. Four field single phase conformal therapy with 28 fractions costs 5723 Canadian dollars. The cost of conventional radiotherapy over 33 fractions was 3068 Canadian dollars. The majority of the cost differences arose from the cost of the additional time needed for treatment per day as well as the extra fractions per patient when compared to conventionally treated patients. The average treatment times per fraction for six field conformal, four field conformal and four field conventional have the median times of 22.72, 20.63 and 11.07 minutes respectively. Planning costs for conformal radiotherapy were up to three times the cost of conventional therapy.

CONCLUSIONS

The direct costs of dose escalated conformal external beam radiotherapy are over 2.5 times that of conventional external beam radiotherapy for early stage prostate cancer. These direct costs are a reflection of the additional capital and human resources needed to provide state-of-the-art radiation therapy in the province of Ontario. Planning for radiation oncology needs should consider the additional costs of conformal external beam radiotherapy.