Architecture for boost DC_DC for APD bias

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Now I start a boost dc-dc project. And I don't know what architecture is more suitable.         
          Design goal: input 3.3V
                              output 30~60V, Iload=2mA.
         
          There are PFM and PWM two options. But all the related chip using the PWM method such as MAX15031/LT
3571.  The PFM is more simple and stable, while PWM is more complex, why they choose that?

          The max output current is 2mA, so little load is suitable to PFM rather than PWM.

          For the related chip, they all choose the DCM not CCM for PWM,  Based on what to choose DCM or CCM?