non-indigenous cases; advanced stage breast cancer was seen in 55% of cases, compared with 38% of non-indigenous cases; and advanced colorectal cancer was seen in 57% of cases, compared with 48% of non-indigenous cases. Lung cancer was the only cancer where indigenous patients presented with earlier stage cancers, perhaps because of detection by chest X rays taken as part of tuberculosis screening. In LMICs, lung cancer is usually found at 51 more advanced stages. Reports of the distribution of stages of lung cancer are scant; a pattern of care study in Turkey showed that 72% of cases of lung cancer were stage III or IV [3.27]. Radiotherapy is often the only treatment option for advanced cancers. 3.5. CALCULATING THE DEMAND FOR RADIOTHERAPY MACHINES The demand for radiotherapy services is made up of treatments for new cases and re-treatments for recurrence or cancer spread. About 50% of new cases of cancer would benefit from radiotherapy and about 25% of these may benefit from further treatments [3.28]. The re-treatment rate may be lower in LMICs with limited resources that prioritize palliative treatment. The bulk of radiotherapy is delivered by 60Co or linear accelerator machines. These machines deliver high energy X rays in the megavoltage range and are known collectively as megavoltage (MV) machines. The capacity of an MV machine is between 400 and 600 courses of treatment per year. These courses will include new patients, re-treatments (second or subsequent treatment) and treatment of non-malignant disease cases such as pituitary tumours or those not notified to a cancer registry such as non-melanomatous skin cancer. The potential number of new cases with an indication for radiotherapy and the number receiving second or subsequent courses (re-treatment) in a geographical region can then be used to calculate the number of MV units required in that region. This can be compared against the actual supply of units in a country or region to determine the shortfall. In practice, it is better to use two scenarios that reflect the different demands and conditions in high income countries and in LMICs. In LMICs, the demand for radiotherapy is likely to be greater (see above), radiotherapy techniques are often less complex and operating hours are longer because staff wages are relatively low [3.29]. Thus, the radiotherapy utilization rate will be higher, the number of courses per machine will be higher and the re-treatment rate will be lower (Table 3.3). Table 3.4 and Fig. 3.3 show these calculations for IAEA regions. Only in North America and the Middle East does the number of MV machines approach or exceed calculated optimal demand using the high income planning parameters. Mexico, Central and South America, Southern and Western Pacific and Western Europe all have more MV machines than required for the low and middle income parameters. 52 TABLE 3.3. PARAMETERS FOR CALCULATING DEMAND FOR MV MACHINES Low and middle income countries High income countries Optimal utilization rate 55% 50% Re-treatment 10% 25% New courses per MV machine per year 600 400 TABLE 3.4. OPTIMAL CALCULATED NUMBER OF MV MACHINES VERSUS ACTUAL SUPPLY (cont.) IAEA region Demand for MV machines Actual number of MV machines LMICs High income countries Caribbean 68 117 46 Central Africa 87 149 14 East Africa 137 234 11 East Asia 3551 6054 2660 Eastern Europe and Northern Asia 1141 1945 891 Indian Ocean Islands 15 26 4 Mexico and Central America 156 266 167 Middle East 156 266 346 North Africa 134 228 121 North America 1566 2669 4258 South Asia 1238 2111 581 53 TABLE 3.4. OPTIMAL CALCULATED NUMBER OF MV MACHINES VERSUS ACTUAL SUPPLY (cont.) IAEA region Demand for MV machines Actual number of MV machines LMICs High income countries Southeast Asia 651 1110 215 Southern Africa 88 151 71 Southern and Western Pacific 120 204 189 Temperate South America 151 258 181 Tropical South America 477 813 534 West Africa 127 216 17 Western Europe 2030 3461 2624 FIG. 3.3. Actual versus optimal number of MV machines. 54 3.6. OPTIMAL GEOGRAPHICAL LOCATION OF RADIOTHERAPY