<PAGE>

                      SECOND ASSIGNMENT OF AND AMENDMENT TO
                       THE PROFESSIONAL SERVICES AGREEMENT
                         FOR RADIATION THERAPY SERVICES

                                     BETWEEN

                     USCC HEALTHCARE MANAGEMENT CORPORATION,
                     RADIATION ONCOLOGY MEDICAL GROUP, INC.
                           USCC MEDICAL GROUP-CA, INC.
                             USCMC-USCC PARTNERSHIP
                                       AND
                       THE PERMANENTE MEDICAL GROUP, INC.

THIS SECOND ASSIGNMENT OF AND AMENDMENT TO AGREEMENT ("Second Assignment and
Amendment") is made and entered into as of April 1, 2001, by and between The
Permanente Medical Group, Inc., a California professional medical corporation
("TPMG"), Radiation Oncology Medical Group, a California professional medical
corporation ("ROMG"), USCC Health Care Management Corporation, a California
corporation ("USCC"), USCC Medical Group-CA, Inc., a California professional
medical corporation ("USCCMG-CA"), The USCMC-USCC Partnership, a partnership
between US Cancer Management Corporation and USCC ("PARTNERSHIP") and AuSam
Medical Group, Inc., a California professional medical corporation ("AUSAM").

                                  I. BACKGROUND

A. USCC, ROMG, and TPMG have heretofore entered into an agreement effective
August 1, 1999, for the provision of radiation therapy Services for Members (the
"Agreement").

B. USCC, ROMG, TPMG, USCCMG-CA and PARTNERSHIP executed an Assignment and
Amendment to the Agreement on August 1, 2000, (the "First Assignment and
Amendment") in which the parties made two separate assignments of and amendments
to the Agreement. Those two assignments and amendments related to:

         1. Assignment and Amendment #1 - Stockton Center

         2. Assignment and Amendment #2 - San Rafael, Santa Rosa, and Future
         Centers

C. The parties hereto desire to amend the Agreement in the manner hereinafter
set forth.

NOW THEREFORE, in consideration of the mutual promises set forth herein and for
other good and valuable consideration, the receipt and sufficiency of which are
hereby acknowledged, the parties agree as follows:

                             II. GENERAL AGREEMENTS

A. EFFECTIVE DATE. Effective April 1, 2001, except as otherwise specifically
noted below, the Agreement is amended as set forth below.

B. PRESERVATION OF TERMS. All other terms and conditions of the Agreement are to
remain the same.

C. ROMG RIGHTS AND DUTIES. In accordance with this Second Assignment and
Amendment, the parties understand and agree that ROMG will no longer retain any
rights, obligations or duties under the Agreement after August 1, 2001, except
as may have arisen prior to that date.


<PAGE>

D. BINDING ON SUCCESSORS. The terms of this Second Assignment and Amendment
shall be binding on the parties' successors and assigns.

E. COUNTERPARTS. This Second Assignment and Amendment may be executed in two or
more counterparts, each constituting an original and all taken together
constituting one and the same document.

F. DESIGNATION. The parties agree that, hereinafter, all references in the
Agreement to ROMG shall now also refer to AUSAM as it pertains to obligations
and privileges of the parties for their respective centers. The term
"Contractor" shall jointly and separately refer to USCC, PARTNERSHIP, ROMG,
AUSAM and USCCMG-CA.

                III. ASSIGNMENT AND AMENDMENT #3 - HAYWARD CENTER

A.       THE RECITALS OF THE AGREEMENT ARE AMENDED AS FOLLOWS:

         1. SECTION L is added as follows: "L. AUSAM is a California
         professional medical corporation that provides outpatient radiation
         oncology services. AUSAM's TIN number is: 94-3394639 and its California
         Corporation number is 2334027."

         2. SECTION M is added as follows: "M. USCC, ROMG and TPMG desire to
         have AUSAM provide Services at the East Bay Regional Cancer Center
         ("Hayward Center"). At this time, ROMG desires to assign its rights,
         interest and obligations under the Agreement related to the Hayward
         Center to AUSAM."

B.       THE TERMS OF THE AGREEMENT ARE ASSIGNED AND AMENDED AS FOLLOWS:

         1. ASSIGNMENT. ROMG hereby assigns and transfers to AUSAM all right,
         title and interest in and to the Agreement related to the Hayward
         Center, effective August 1, 2001.

         2. ACCEPTANCE OF ASSIGNMENT. AUSAM hereby accepts assignment and
         transfer of all right, title and interest in and to the Agreement, and
         expressly assumes all of the rights, liabilities (beginning August 1,
         2001) and responsibilities of ROMG under the Agreement pertaining to
         the Hayward Center and agrees to perform and be bound by all terms,
         conditions and obligations of the Agreement for Services AUSAM provides
         at the Hayward Center.

         3. AUSAM REPRESENTATIONS AND WARRANTIES. AUSAM represents and warrants
         that it (a) has the authority to execute this Second Assignment and
         Amendment, and (b) has assumed all obligations and liabilities of ROMG
         relating to the Hayward Center arising under or related to the
         Agreement arising on or after August 1, 2001.

         4. ROMG REPRESENTATIONS AND WARRANTIES. ROMG represents and warrants
         that it has acquired tail insurance coverage for liabilities arising
         prior to August 1, 2001, in amounts equivalent to not less than the
         minimum insurance coverage required of ROMG under the Agreement prior
         to assignment, and satisfactory to TPMG. ROMG represents and warrants
         that it shall maintain such tail insurance in full force and effect for
         a period of ten (10) years following the effective date of this Second
         Assignment and Amendment. ROMG shall provide adequate evidence of such
         insurance to TPMG upon TPMG's request at any time.

         5. TPMG CONSENT. TPMG hereby consents to the assignment of rights and
         assumption of duties described in this Article III.


                                       -2-
<PAGE>

         6. NOTICES. The parties hereby agree that all notices regarding the
         Hayward Center required under the Agreement to be directed to ROMG
         shall henceforth be directed to AUSAM at the following address:

                           AUSAM Medical Group, Inc.
                           c/o US Cancer Care
                           700 Ygnacio Valley Rd., #300
                           Walnut Creek, CA   94596

         7. PAYMENT BY KP. The parties acknowledge and agree that all payments
         due and owing from KP to ROMG pursuant to the Agreement for the Hayward
         Center shall, for Services on or after August 1, 2001, be made to
         AUSAM, provided, however, that disputes involving KP's payment (a) to
         ROMG of amounts owing to AUSAM, or (b) to AUSAM of amounts owing to
         ROMG, shall be resolved between ROMG and AUSAM without liability on the
         part of KP.

                        IV. ASSIGNMENT AND AMENDMENT #4 -
               FRESNO, SAN RAFAEL, SANTA ROSA, AND FUTURE CENTERS

A.       THE RECITALS TO THE AGREEMENT ARE FURTHER AMENDED AS FOLLOWS:

         SECTION N is added as follows: "N. The parties acknowledge that
         PARTNERSHIP and TPMG are currently planning to develop new Service
         centers in the Santa Rosa and Fresno areas. Further, development of a
         Service center in the San Rafael area has been suspended as of April 1,
         2001. At this time, ROMG desires to assign its interest and obligations
         under the Agreement and the First and Second Assignments and
         Amendments, as related to the Service centers that the parties desire
         to develop in the future, including but not limited to the currently
         planned Santa Rosa and Fresno Centers, to USCCMG-CA. This assignment
         relieves ROMG of any and all future interest or obligation in the
         Agreement."

B.       THE TERMS OF THE AGREEMENT ARE FURTHER ASSIGNED AND AMENDED AS FOLLOWS:

         1. ASSIGNMENT. ROMG hereby assigns and transfers all right, title and
         interest in and to the Agreement for Services provided at the Santa
         Rosa and Fresno Centers and such future centers that the parties
         develop, to USCCMG-CA, effective as of April 1, 2001.

         2. ACCEPTANCE OF ASSIGNMENT. USCCMG-CA hereby accepts assignment and
         transfer of all right, title and interest in and to the Agreement, and
         expressly assumes and agrees to perform and be bound by all terms,
         conditions and obligations of ROMG under the Agreement for Services
         provided at the Santa Rosa and Fresno Centers and such future centers
         as the parties may develop.

         3. USCCMG-CA REPRESENTATIONS AND WARRANTIES. USCCMG-CA represents and
         warrants that it (a) has the authority to execute this Second
         Assignment and Amendment, and (b) has assumed all obligations and
         liabilities of ROMG arising from the Santa Rosa and Fresno Centers and
         such future Centers that the parties may develop under or related to
         the Agreement arising on or after April 1, 2001.

         4. ROMG REPRESENTATIONS AND WARRANTIES. ROMG represents and warrants
         that no Services were provided under the Agreement as part of the Santa
         Rosa and Fresno Centers before April 1, 2001, and, thus, no tail
         insurance for prior periods is required.

         5. TPMG CONSENT. TPMG hereby consents to the assignment of rights and
         assumption of duties described in this Article IV of the Second
         Assignment and Amendment.


                                       -3-
<PAGE>

         6. NOTICES. The parties hereby agree that all notices regarding the
         Fresno, Santa Rosa or future centers required under the Agreement to be
         directed to ROMG shall henceforth be directed to USCCMG-CA at the
         following address:

                           USCCMG-CA
                           c/o US CancerCare
                           700 Ygnacio Valley Rd., #300
                           Walnut Creek, CA   94596

         7. PAYMENT BY KP. The parties acknowledge and agree that all payments
         due and owing from KP to ROMG pursuant to the Agreement for the Santa
         Rosa and Fresno Centers and such future Centers that the parties
         develop shall hereinafter be made to USCCMG-CA, provided, however, that
         disputes involving KP's payment (a) to ROMG of amounts owing to
         USCCMG-CA, or (b) to USCCMG-CA of amounts owing to ROMG, shall be
         resolved between ROMG and USCCMG-CA without liability on the part of
         KP.

         8. ASSUMPTION OF COSTS AND EXPENSES RELATING TO THE SAN RAFAEL CENTER.
         In the event any party has incurred expenses or costs in preparation
         for or anticipation of the opening of the San Rafael Center, each
         party, including without limitation ROMG and TPMG, agrees to absorb its
         own expenses and costs. Further, all parties agree to waive their
         rights to recover any such costs or expenses from any other party by
         virtue of the decision to suspend development of the San Rafael Center.

         9. ASSUMPTION OF COSTS AND EXPENSES RELATING TO THE SANTA ROSA AND
         FRESNO CENTERS. In the event ROMG has incurred any expenses or costs in
         preparation for or anticipation of the opening of the Santa Rosa or
         Fresno Centers, ROMG agrees to absorb its own expenses and costs.

         10. WAIVER OF INTEREST IN FUTURE DEVELOPMENT. ROMG hereby waives and
         abandons any right, title or interest it may have under law or the
         Agreement to the development or operation of the Santa Rosa Center, the
         Fresno Center, and any other future center, if ever such development
         and operation may occur.

                            V. ADDITIONAL AMENDMENTS

A.       CONFIDENTIAL TERMS HAVE BEEN OMITTED AND FILED SEPARATELY WITH THE
         SECURITIES AND EXCHANGE COMMISSION

B.       CONFIDENTIAL TERMS HAVE BEEN OMITTED AND FILED SEPARATELY WITH THE
         SECURITIES AND EXCHANGE COMMISSION

C.       CONFIDENTIAL TERMS HAVE BEEN OMITTED AND FILED SEPARATELY WITH THE
         SECURITIES AND EXCHANGE COMMISSION

D.       EXHIBIT 3 IS MODIFIED AS FOLLOWS:

         1. Exhibit 3A (Hayward) is amended to add the attached Exhibit 3A-1 to
         address budget and rates for the Hayward Center effective August 1,
         2000.

         2. Exhibit 3B (Stockton), Exhibit 3C (San Rafael), and Exhibit 3D
         (Santa Rosa) are hereby deleted and replaced by the attached Exhibit 3B
         (Stockton), Exhibit 3C (Fresno), and Exhibit 3D (Santa Rosa).

E.       SECTION 3.2 IS HEREBY DELETED AND REPLACED WITH THE FOLLOWING:

         3.2 PAYMENT OF COMPENSATION. In accordance with the provisions of
         Section 3 and Exhibit 3 of this Agreement, TPMG shall pay Contractor
         for Covered Services rendered to


                                       -4-
<PAGE>

         Members. Contractor shall accept such amounts paid by TPMG and any
         Copayments Contractor is directed to collect, as payment in full.
         Emergency Services must be Approved Emergency Claims (pursuant to
         Section 2.3) and other Services must be Authorized Services (pursuant
         to Section 2.4) as a condition for payment. Payment for Covered
         Services shall be made within thirty (30) working days of receipt of a
         properly submitted and undisputed invoice as described in Exhibit 4, or
         within such other time frame as may be required by applicable federal
         or state laws, rules or regulations. Both parties shall use reasonable
         efforts to resolve disputes regarding invoices in accordance with
         Section 8.1. Upon resolution of the dispute, the invoice shall be paid
         within thirty (30) working days of the date of resolution. Interest and
         penalties on any late payments will be paid as required of Health Plan
         by law.

F.       SECTION 4.1 IS HEREBY DELETED AND REPLACED WITH THE FOLLOWING:

         "4.1 TERM. This Agreement will begin on the effective date (specific to
         each Center), and will continue in effect for three (3) years for the
         Hayward and Stockton Centers and five (5) years for the Santa Rosa and
         Fresno Centers, and such future Centers as the parties may develop.
         This Agreement will thereafter automatically renew for each Center for
         successive five (5)-year terms based upon each Center's initial
         effective date, unless terminated in accord with Sections 4.2, 4.3, or
         4.4, below. Further, if any party desires to allow the Agreement as it
         relates to any particular center to expire at the end of the initial or
         any subsequent term for that specific center, the party shall give
         written notice of such intent to the other party at least One Hundred
         Eighty (180) days prior to the end of that term."


G.       CONFIDENTIAL TERMS HAVE BEEN OMITTED AND FILED SEPARATELY WITH THE
         SECURITIES AND EXCHANGE COMMISSION


H.       SECTION 4.3(a) IS HEREBY AMENDED AS FOLLOWS (ADDITIONS INDICATED BY
         UNDERLINING, DELETIONS INDICATED BY STRIKEOVER):

         "4.3 IMMEDIATE TERMINATION.

                  (a) Each party to this Agreement shall immediately notify TPMG
         and TPMG may immediately suspend this Agreement as it relates to that
         party in the event there is a material adverse change in any insurance
         coverage required of that party hereunder, other than a cancellation,
         non-renewal, expiration or failure to obtain coverage. If the party
         does not provide adequate insurance coverage within thirty (30) days of
         the material adverse change, TPMG may terminate this Agreement as it
         relates to that party immediately. Each party shall immediately notify
         TPMG and this Agreement will terminate as it relates to that party
         without further action of the any parties if such insurance coverage is
         canceled, not renewed or expires, or if that party fails to obtain any
         insurance coverage as required by this Agreement. If this Agreement
         terminates without further action of the parties, the effective date of
         termination shall be the date of the occurrence of such event or, at
         TPMG's option, such other date as determined by TPMG in its sole
         discretion."



                                      -5-
<PAGE>




I.       SECTION 4.3(c) IS HEREBY AMENDED AS FOLLOWS (ADDITIONS INDICATED BY
         UNDERLINING, DELETIONS INDICATED BY STRIKEOVER):

         "4.3 IMMEDIATE TERMINATION.

                  "(c) Each party to this Agreement shall notify TPMG and TPMG
         may terminate this Agreement or the Agreement as it relates to that
         party immediately upon written notice to Contractor if any party to
         this Agreement files a petition in or for bankruptcy, reorganization or
         an arrangement with creditors; makes a general assignment for the
         benefit of creditors; is adjudged bankrupt; is unable to pay debts as
         they become due; has a trustee, receiver or other custodian appointed
         on its behalf, or has a case or proceeding commenced against it under
         any bankruptcy or insolvency law."


J.       SECTION 9.5 IS HEREBY DELETED AND REPLACED WITH THE FOLLOWING:

         "9.5 ASSIGNMENT. Subject to the provisions related to successors set
         forth below, neither this Agreement nor any duties or obligations under
         this Agreement may be assigned or subcontracted by USCC, PARTNERSHIP,
         AUSAM and/or USCCMG-CA without the prior written consent of TPMG. TPMG
         agrees that such consent shall not be unreasonably withheld. TERMS HAVE
         BEEN OMITTED AND FILED SEPARATELY WITH THE SECURITIES AND EXCHANGE
         COMMISSION. Any material change of ownership or control of USCC,
         PARTNERSHIP, AUSAM and/or USCCMG-CA shall be deemed an assignment of
         this Agreement requiring the prior written consent of TPMG. If
         Department of Health Services' ("DHS") or a Medi-Cal Plan's approval is
         required by law or Health Plan Medi-Cal Contracts, assignment or
         delegation of this Agreement shall be void unless prior written
         approval is obtained from DHS and/or such Medi-Cal Plan."

               THE REMAINDER OF THIS PAGE INTENTIONALLY LEFT BLANK


                                      -6-
<PAGE>




         IN WITNESS WHEREOF, the parties have caused this Second Assignment and
         Amendment to be executed by their respective duly authorized
         representatives as of the dates set forth below.



THE PERMANENTE MEDICAL GROUP, INC.

By:  /s/ Philip Madvig
   --------------------------------------------------
     Philip Madvig, M.D.
     TPMG Associate Executive Director

Date: 8/29/01
     ------------------------------------------------

Reviewed By: /s/ Bellinda Rossmiller
            -----------------------------------------
     Bellinda Rossmiller, Administrator
     Med. Svcs. Planning & Contracting Support

     Date: 9/5/01
          -------------------------------------------




RADIATION ONCOLOGY MEDICAL GROUP, INC.

     By: /s/ Harry Newman
        --------------------------------------------
     Name:  Harry Newman, M.D.
          ------------------------------------------
     Title:  President
           -----------------------------------------
     Date:  8/16/01
          ------------------------------------------

USCC HEALTH CARE MANAGEMENT CORP.

     By:  /s/ Richard Padelford
        --------------------------------------------
     Name:  Richard Padelford
         -------------------------------------------
     Title:  President
           -----------------------------------------

     Date:  8/28/01
          ------------------------------------------

USCC MEDICAL GROUP-CA, INC.

     By:  /s/ Barry Tepperman
        ----------------------------------------------
     Name:  Barry Tepperman
          --------------------------------------------
     Title: President
           -------------------------------------------
     Date:  8/21/01
          --------------------------------------------

USCMC-USCC PARTNERSHIP

     By:  /s/ W. Brian Fuery
        ----------------------------------------------
     Name:  W. Brian Fuery
          --------------------------------------------
     Title:  CEO
           -------------------------------------------
     Date:  8/20/01
          --------------------------------------------

AUSAM MEDICAL GROUP, INC.

     By:   /s/ Samuel P. Au
        ----------------------------------------------
     Name: Samuel P. Au, M.D.
          --------------------------------------------
     Title:  President
           -------------------------------------------
     Date:  8/17/01
          --------------------------------------------



                                       -7-