Vague pain in abdomen, lump in abdomen, fever, sometimes hematuria, weight loss are few of symptoms of kidney tumor. Although early tumor are often detected incidentally.

Early tumor stage 1 a are often incidentally diagnosed and have very good chances of cure.

CT scan characteristics are often diagnostic of renal carcinoma, hence biopsy is not must.
However when scan doubtful then biopsy is done.

CT scan chest abdomen and bone scan or PET scan is done to find out spread.

Kidney cancer is chemo/radioresistant.
Only curative treatment is surgery.
Whenever feasible, kidney sparing surgery is preferred (partial nephrectomy) When tumor is large, radical nephrectomy (removal of kidney with lymph nodes) is done
Both partial/total nephrectomy can be done laparoscopically.
Sometimes you need vascular cover (help of vascular surgeon) if tumor spreading along renal vein into inferior vena cava (large blood vessel which carry blood from body to heart).

When limited spread, to decrease tumor burden, nephrectomy is done so that targeted therapy act more efficiently

Renal tumor is not responding to chemotherapy. It respond to immunotherapy and targeted therapy. Targeted therapy are drugs given orally which act only on cancer cell without affecting normal cells hence side effect of chemotherapy are not there.

If tumor spillage happens at the time of surgery, radiotherapy is given to decrease chance of recurrence.