Non Hodgkin Lymphoma - length of compensation

[Gone Fishing]

I was diagnosed with Non-Hodgkin Lymphoma in July of 2018, and started a combination of Chemo treatments & Biologics (Rituximab) later that month.  The claims process was started in August.  My last chemo treatment was December.  Scans in Jan showed the cancer was in remission, but I will continue to be treated with the Rituximab drip every 2 months for 2 years.

I am not using the VA for treatments, but instead going through Medicare and supplement policies provided by my employer.

I received a letter from the VA for an evaluation.  My question is, what are the regulations regarding the disability ratings and length of time?  I read somewhere that compensation continues for 12 months after treatments, but the definition of treatments was not spelled out.  Really would appreciate some clarity on this.