It's my second day at the American Society of Clinical Oncology (ASCO) annual meeting down in Orlando, Florida. Here are the highlights:

Ovarian Cancer: Regular CA 125 monitoring is NOT beneficial in women with ovarian cancer

Researchers reported findings from a study of women who had completed their ovarian cancer treatment and were given the CA 125 blood test every three months. If the test showed that their CA 125 levels doubled, they were randomized to either do nothing or to start chemotherapy. The women who were treated on the basis of rising CA 125 were treated 4 months earlier, but the early intervention did not improve overall outcomes. (In fact, they may have experienced higher toxicity from starting early chemotherapy.) To me, this means it's better to wait to see if any symptoms of recurrence occur. This quandary is just like breast cancer, where monitoring of blood markers makes no difference in the outcome. Either the tumor is sensitive to chemotherapy, in which case it doesn't matter when you do it, or it is not. If it's not, it doesn't matter when you undergo chemotherapy.

Breast Cancer: PARP Inhibitors

Women with BRCA1 or BRCA2 have a gene mutation that increases their risk of developing breast and ovarian cancer. If the BRCA 1 or 2 gene develops a second mutation, cells can no longer do a double-strand DNA repair. This leaves cells stuck with a single-strand repair (base pair excision) using PARP.

In one study from the UK, women with metastatic breast cancer who had had at least three previous treatments with chemotherapy were given an oral PARP inhibitor; some received a high dose, others a low dose. Researchers indicated that 41% of women who received the higher of the two doses responded, and one woman had a complete disappearance of her tumor. There were no side effects reported. This is an important finding, as there are 9,000 newly diagnosed breast cancers in women with BRCA1/2 a year in U.S.

Even more interesting was the U.S. study presented by Joyce O'Shaunghnessy on the effectiveness of PARP inhibitors in women with triple negative breast cancer (15% of all breast cancers with a 30% relapse after treatment). 75% of women with BRCA 1 or BRCA 2 breast cancers are triple negative, but most triple negative breast cancers are NOT in BRCA carriers. Researchers did a phase two study of chemotherapy with or without an IV PARP inhibitor in women with metastatic disease. There was a 65% reduction in the rate of relapse and a 60% reduction in the risk of death, both of which were statistically significant. The treatments were also well tolerated. Now researchers will do a phase three of the study. This is important because it suggests that women with this type of cancer may have defects in BRCA in their tumors even though they are not carriers, and that this targeted therapy may work on a broader population of women.  This is the one breast cancer group without a targeted therapy (aromatase inhibitor/tamoxifen for ER/PR+ tumors; Herceptin for HER2-positive tumors).

Some additional findings from the sessions:

Sentinel Node Biopsy: Studies looked at whether the axilla needs to be treated after a sentinel node biopsy. Findings: If there are just a few isolated tumor cells, then you probably do not. But if there are micrometastases, you do.

Post-Mastectomy Radiation: Is post-mastectomy radiation important in women with 1-3 positive nodes and tumors less than 5 cm? A study suggests that it is worth it, but the study was a retrospective, non-randomized one, so more investigation needs to be done.

SSRI's and Tamoxifen: Do SSRI's interfere with the benefits of tamoxifen? Tamoxifen is metabolized in the liver into the active ingredient endoxifen. The enzyme that does this can be blocked by certain drugs, most specifically SSRI's such as paroxetine and fluoxetine. One study suggests that the SSRI's did make a difference in recurrence rate and the other study suggests that they didn't. Probably best to avoid them.

Aromatase Inhibitors and Chemobrain: Are aromatase inhibitors a bigger cause of chemobrain than tamoxifen? This study did not start with baseline tests, but compared women to normal controls. None the less they found that tamoxifen was worse for your brain then letrozole. Since HRT increases dementia, it may be that estrogen is not so good for the brain after all!

Node Negative Breast Cancer: Are there markers that can predict which node negative breast cancer patients do not need hormones or chemotherapy? A European study showed 10 year prospective data that uPAH and PAI levels predict a group with a ten year survival with no systemic therapy. Unfortunately, these markers although approved in this country are not used because they require fresh frozen tissue and we don't usually save that.

Oncotopye DX and MammaPrint: The two multiple gene tests available in this country have less data than uPAH and are only starting their large prospective studies.  Mammaprint presented a collection of retrospective studies and has a prospective study MindAct currently underway. Oncotype DX is doing a larger study, the TailorRX, which will answer the prospective question as well. Interestingly all three markers seem to detect about 40-45% of 'good' cancers that don't need chemotherapy.

The I-SPY Trial: The final presentation of this breast session was Laura Esserman's report from the I-Spy study. In this large, multi-center trial women with large cancers have multiple samples and images taken before, during, and after neoadjuvant chemotherapy (chemo before surgery). The interesting finding was that they could also differentiate with gene patterns between a 'good' kind and a 'bad' kind of breast cancer.  The women with the good kind do well even if they don't respond that well to the preoperative chemotherapy, while the women with the more aggressive kind do well only if they respond well to the preoperative chemotherapy. This is intriguing and just the first of many important findings that will come from this detailed study.