Early chemo treatments most effective

I realize that early chemo (first and second line) are usuually most effective and %'s drop for 3rd and 4th line chemo. But have any of you been told that the early treatments in a round of chemo have most of the effect. I know that I have read comments where many of you had significant CA 125 drops and shrinkage on scan after first 3-4 treatemts and wanted to stop chemo there. I am trying ton get armsd around my most recent experience. I had to wait 2 months (NOv-Jan. 2011) for my onc to get Cisplatin and Adriamycin and my number of tumors in pulmonary area doubled. After the first 4 treatments (we planned 7 but ending up stopping at 6), the scan showed "partial response" with shrinkage of roughly 30%. The next chemos were brutal(nausea, tanking blood values, hospital stay, transfusions, lost 20 lbs.etc). We cancelled # 7 as weight loss and blood values suggested we should stop at 6 on the Adriamycin to mitigate risk of heart damage. Scan about 6 weeks out showed essentially no change since midterm scan and also showed areas of suspicious tissue density requiring a PET scan. I see my doctor in a couple of weeks(for PET results) and expect the what next conversation and now realize we are probbly at the stopping progression phase rather than hoping for lengthy remission (that was the hope for this last combo of drugs). Also I suspect I am either platinum resistant or chemo resistant as first recurrence was at 5 months and second was at 4 months. I thought about tissue assay but my doctor is not a big believer and recent articles create questions about value. I still have topotecan,gemzar and Avastin out there but am starting to worry about 6 months of treatment where each subsequent chemo takes toll on the body and shorter respites create questions on quality of life. I feel I am going into a new phase of the battle and can use guidance on how to handle and what questions I need to be asking my doctor.