SCLC bone mets

I was diagnosed with limited stage small cell lung cancer in March of 2017 and underwent 4 rounds of chemo (cisplatin and etoposide) and 33 radiation treatments. Treatment went well and we hoped I was cured. In March 2019 started having pain in my knee which urgent care doctor said was osteoarthritis. Meanwhile had usual mid-thigh maintenance scans which remained clear. Pain got worse, and physicians assistant referred me to orthopedic doctor, who took lateral xrays and found lytic lesion in the distal (bottom) femur behind my knee. These xrays were the first scans anyone had done of this area. SEVEN MONTHS after first knee pain, I had rush knee replacement surgery and tumor was determined to be metastatic small cell lung cancer. So far have not found cancer anywhere else. My doctors said this never happens; ortho oncology surgeon said oh, yeah, I've seen this before. My point here is, I should have taken the new pain seriously and insisted on getting it checked out. I found out that lung cancer and some colon cancer can metastisize anywhere. I am back on chemo and doing well, but could have saved myself months of pain. From now on I will be a better advocate for myself.