If the cancer continues to grow the chemo is stopped and other drugs sought. If the cancer is responding but the kidneys or other complications set in, maybe stopping temporarily till things improved, then resuming treatments.
Depending on the criteria, there are many clinical trials investigating new drugs, combos and some targeted therapies like Avastin if the first treatment fails...there are 'second line treatments."
If there was a tumor to target, spot radiation could help control symptoms.
All the best,
Wendy