The member tt(genCases) performs one complete iteration over all screening
rounds for all simulated cases. The option tt(nCases) may be used to simulate
a specific number of cases. When tt(nCases) is specified only the data of the
final case are written to file. By default as many cases as specified at the
`nWomen' parameter (stored in the tt(Scenario) object) are simulated, and the
data of all those simulated cases are written to file. Analyses up to a
specific number of cases, or a single simulation using a preset death-age (see
option tt(--death-age) in the bf(simrisc)(1) man-page) can also be
performed. The number of cases to simulate is determined in the tt(nCases)
member.

For each simulated case:
itemization(
it() the simulation data are initialized:
    itemization(
    it() the costs of the case (tt((d)_caseCost)), the tumor-caused death age
        (tt(d_deathAge)), the screening round in which a tumor is detected
        (d_roundDetected), and the indicator indicating whether the tumor has
        been self-detected (d_selfDetected);

    it() breast density indices are determined (uses random numbers, and thus
        they are recomputed at each new simulated case) (cf. section
        ref(DENSITIES)). These indices are stored in tt(d_indices) for the
        different screening ages (the index computed for the first screening
        age is stored at the first element). For each age a randomly
        determined proportion is located in the cumulative proportions of the
        bi-rads categories of its age group. The thus determined bi-rad
        category is stored in tt(d_indices). E.g., for age 54 these bi-rads
        proportions could be used: 
       verb( 
                  agegroup  bi-rads1  bi-rads2  bi-rads3  bi-rads4
breastDensities:  50 - 60   0.08      0.50      0.37      0.05
        )
        resulting in category 3 if the randomly selected proportion is 70;

    it() cumulative total tumor risks are determined (uses breast density
        indices, and must therefore be recomputed at each simulated case)
        (cf. section ref(TUMORINFO));

    it() the case's natural death age is determined as a random age <=
        MAX_AGE, which is a compiled constant (100).

    it() the status of the simulated case is intialized to tt(PRESENT). The
        case's state changes during the simulation and the case's simulation
        may end during the pre-screening phase, the screening phase, or the
        post-screening phase, because of the case's natural death, because of 
        self-detection of a tumor or because of a tumor that's detected during
        a screening cycle;

    it() the parameters of the tumor-simulating object are reset (cf. section
        ref(TUMORRESET)).
    )

it() following the initialization three simulation phases are simulated:
    itemization(
    it() pre-screening (cf. section ref(PRESCREEN))
    it() screening (cf. section ref(SCREENING))
    it() postscreening (cf. section ref(POSTSCREEN))
    )

it() Once a case's simulation ends the case's death age and computed costs
    are accumulated and the simulated data are written to the data file
    containing all case-specific values (or, when the option tt(--nCases) or
    tt(--death-age) was specified: only the data of the requested single
    simulated case).
)
